DOCUMENT RESUME

ED 246 300 CE 039 362

AUTHOR Batchelor, Leslie A.; Abercrombie, Richard, Ed.

TITLE Heavy Duty Mechanics Apprenticeship Training, Module
One. Volume II.
INSTITUTION British Columbia Dept. of Education, Victoria.
REPORT NO ISBN-0-7718-8234-3
PUB DATE [80]
NOTE 266p.; For volume I, see CE 039 361.
AVAILABLE FROM Publication Services Branch, Ministry of Education,
878 Viewfield Road, Victoria, BC V9A 4V1 (Set of two
volumes--$15.00).
PUB TYPE Guides - Classroom Use Materials (For Learner)
(051)

EDRS PRICE MF01 Plus Postage. PC Not Available from EDRS.

DESCRIPTORS *Apprenticeships; *Auto Mechanics; Electric
Batteries; Electric Circuits; *Electricity; Electric
Motors; Electronic Equipment; *Engines; Equipment
Maintenance; Equipment Utilization; Foreign
Countries; Hand Tools; Inservice Education; Job
Skills; Machine Tools; Magnets; *Mechanics (Process);
On the Job Training; Postsecondary Education; Safety;
School Shops; *Trade and Industrial Education
IDENTIFIERS British Columbia; *Heavy Equipment Mechanics;
Ignition Systems

ABSTRACT
This training manual, the second of two volumes,
comprises the final three blocks in a nine-block in-service training
course for apprentices working in heavy duty mechanics. Addressed in
the individual blocks included in this volume are engines, basic
electricity, and winches. Each block contains a section on parts
theory that gives the purpose, topics, operations, and applications
of the parts and systems being discussed; a set of questions on parts
theory; a section on scheduled maintenance and service repair; a set
of questions on service; and a list of validated tasks to be
completed during the course of daily on-the-job routines. The manual
is illustrated with photographs and drawings. (MN)

***********************************************************************
Reproductions supplied by EDRS are the best that can be made
from the original document.
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 Heavy Duty Mechanics
Apprenticeship Training,
Module One
VOLUME II

o S IMPARTMENT or coucarioN
Province ot British Columbia
NATIONAL INSTITUTE OF toucAnoty "PERMISSION TO REPRODUCE THIS
, An.IP.A 41 .. 1.44 i k, ,NI ORMA 10N MATERIAL IN MICROFICHE ONLY
, tNetta lea HAS SEEN GRANTED BY

. ... ,T 0.% .1 . ,t . .I.

TO THE EC JCATIONAL RESOURCES
. 4 ,..

INFORMATION CENTER (ERIC)"

Developed by Program Research and Development.

Ministry of Education
In Cooperation with the
Apprenticeship Training Programs Branch.
Ministry ot Labour

2
Canadian Cataloguing in Publication Data
Main entry under title:
Heavy duty mechanics apprenticeship training.

Prepared for publication by Leslie A. Batchelor ;

Richard Abercrombie, editor.
ISBN 0-7718-823h-3

1. Machinery - Maintenance and repair - Handbooks,

manuals, etc. I. British Columbia. Ministry of
Education. Program Research and Development. II.
British Columbia. Apprenticeship Training Programs
Branch. III. Batchelor, Leslie A. IV. Abercrombie,
Richard.

This manual was prepared for publication by:

Leslie A. Batchelor.
Heavy Duty Mechanics Instructor.
Cariboo College.
Richard Abercrombie. Editor.

3
 ACKNOWLEDGMENTS

We wish to thank the following members of the Heavy Duty Mechanics Trade
Advisory Committee to the Ministry of Labour who were instrumental in
initiating the writing of this manual:

Ken Brown. Coast Tractor and Equipment Ltd.

Art Latto. Kaiser Resources Ltd.
Doug LaVae. Finning Tractor and Equipment Co. Ltd.
Dennis Waunch. International Union of Operating Engineers
A Thygesen. Pulp. Paper and Woodworkers of Canada
Don Staples. B.0 Forest Products Ltd.
Jim Cameron. Utah Mines Ltd.
Dave Baston. AoprenticeshiD Counsellor. Ministry of Labour
Vic Amirault. Program Development Officer. Ministry of Labour

We wisn to also extend our thanks to othe' members of the Heavy Duty
Mechanics Trade Advisory Counc.1 for the support they gave to this manual

0 0,,r,stry or f *Avon PrownCe of BMW) Columbia CanaCa

140 pan of this publication may be reproduced in any
form without permisston rn writino from the publisher

4
 INTRODUCTION

This is an in-service training manual for ap- likely to be doing in your shop. Another set of
prentices working in heavy duty mechanics questions follows the service section The
shops who wish to complete Module One, blocks end with a list of practical tasks that
Heavy Duty Mechanics Apprenticeship should be cnne during daily work at your job
Training in-service. It covers the same `.'our employer has a Task Check Chart, that
material that is taught in the 14 week training he will complete to vouch that you have done
program for Module One at the vocational all the tasks listed in the manual.
schools. Although you don't have an In-
structor to assist you like apprentices at Following is some advice on how to approach
school. you will receive assistance from your the course:
employer and the journeyman you work with.
It is expected that the program will be
The manual is divided into nine blocks: (1) completed within a three month period:
Shop Equipment and Practices, (2) Starting. however. provision is made for up to a
Stopping. Moving Equipment, (3) Hydraulics. three month extension if required. Try
(4) Brakes. (5) Power Trains. (6) Frames. to space the blocks out over the time
Suspension. Running Gear and Working At- you set to do the course There is a lot
tachments, (7) Engines, (8) Electricity. and (9) of material here. and if you leave it all
Winches, Hoists and Cables. The material in to the end. you won't get finished.
blocks 1, 2, 6 and 9 is deal: with in a fairly Monitoring of your progress in the
thorough manner as these subjects won't be course is done by your employer and
covered again in your training courses. The by contact with the Apprenticeship
other blocks. blocks 3, 4. 5. 7 and 8, are intro- Branch. Since this is an individualized
ductions that give a basic gro:nding in their learning package. Were is no one
subjects. The topics in these blocks will be standing over you telling you to do so
covered in greater detail in later courses. The much today and so much tomorrow.
main idea behind the depth that sublects are The onus is on you to keep a regular
studied in this manual is to ty to relate progress through the course. And it
course material to the work you will actually won't be easy.
be doing in the shop at this level of your ap- Don t skip out a section thinking that
prenticeship. This is the reason, for example, you already know it. There probably
that detailed information is given on frames, wilt be material in it that you are un
suFdensions and running gear. whereas only certain of. And besides. if you know
basic informaticn is given on electricity it is most of the material already you'll be
assumed that you will be doing a lot of work able to go through it quickly.
on suspension and running gear. but little on
electrical systems. Stocks 1. 2, 3, 4 and 5 should be done
first. The other blocks can be taken in
Each of the blocks is laid out in the following any order, although it's probably best
pattern: the block begins with a section on to take them in the order in which they
parts theory that gives the purpose, types. come.
operations (how they work) and applications
(where they are used) of the parts and The questions are straightforward:
'here are no trick ones. They can all be
systems being discussed. A set of questier s
follows the parts theory. the answers to which.
answered from a close study of the
are given at the end of the block. Next is a text. Try to do as many of the questions
section on service that is divided into Daily as you can, without going back to the
text. If you can't get a question, then
Routine Maintenance. Scheduled Main- open the text and seek the answer
tenance and Service repair. Daily Routine
rather than t..rning to the answers. This
Maintenance deals with watchful visual way you re-read the topic and get a
checks and adjustments: Scheduled Main- more complete understanding of it than
tenance with scheduled lubrication and it you just look up the answer.
checks: Service Repair with removal,
disassembly, repair or replacement and in- The practical tasks should normally be
stallations. The Service Repair sections in the completed as you work on the material
blocks that are written at a basic level are in each block: however, this may not be
limited to the types of repair that you are

5
 1

practical due to other work com-

mitments in the shop.
N.B. Some tasks may have already
been covered in your day to day
work.
Check with your employer to ensure
that all areas of practical training have
been covered.
When you complete this manual and
4
the practical tasks you will be required
to write an Apprenticeship Branch
examination.

6
 TABLE OF CONTENTS

BLOCK 7 ENGINES
Engines 71
Basic Internal Combustion Engine 7.2
Combustion Theory 7.2
Characteristics of Engines 7.4
Questions - Introduction to Internal Combustion Engine 7.9
Cooling Systems 7.10
Types of Cooling Systems 7.10
Cooling System Components 7.11
Coolant 7.17
Preventive Maintenance Service on Cooling Systems 7.20
Radiator Leakage 7.20
Other Leakage Areas 7.21
Servicing the Cooling Filter 7.23
Belts 7.24
Questions - Cooling System 7.28
Lubrication System 7.31
Lubrication System Components 7.31
Motor Oils 7.36
Preventive Maintenance Service on Lubrication Systems 7.38
Changing Engine Oil 7.39
Questions - Lubrication System 7.43
Air Induction System 7.44
Types of Air Induction Systems 7 44
Intercoolers 7.46
Air Cleaners 7.48
Air Filter Restriction Indicator 7.50
Tubing Hose and Clamps 7.51
Preventive Maintenance on Air Induction Systems 7.53
Air Cleaner Service 7:54
Questions - Air Induction Systems 7.56
Exhaust Systems 7.57
Preventive Maintenance on Exhaust Systems 7.58
Questions - Exhaust Systems 7.60
Fuel Systems 7.61
Gasoline Fuel Systems 7:61
Liquified Petroleum Gas Fuel Systems 7.62
Diesel Fuel Systems 7.64
Basic Components of Gasoline. Diesel and LPG Fuel Systems 7.65
Fuels 7:71
Storing Fuels 7.73
Preventive Maintenance Service of Fuel Systems 7.78
Questions - Fuel and Fuel Systems 7'82
Answers - Internal Combustion Engine 7.84
Answers - Cooling System 7.85
Answers - Lubrication System 7.86
Answers - Air Induction System 7.87
Answers - Exhaust System 7'88
Answers - Fuel and Fuel Systems 7.89
Tasks - Engines 7.90

BLOCK 8 BASIC ELECTRICITY

Basic Electricity 8:1
Functions of Electricity in Heavy Duty Vehicles 81
Electron Theory 8.1
Basic Factors of Electricity 8.2
Basic Electrical Circuit 8.4

7
Electrical Term Definitions 8.4
Basic Electrical Symbols 8.6
Types of Electrical Circuits 8.7
Magnetism 8:10
Electromagnetism 811
Electromagnetic Induction 8.14
Electrical Test Equipment 8.16
Care and Safe Practices with Electrica: Testing Equipment 8.17
Questions - Electricity Theory 8.18
Lead Acid Storage Batteries 8.20
Battery Construction 8.20
Battery Electrolyte 8.21
Battery Operating Cycles . 8.21
The Battery and the Charging Circuit 8.22
Types of Batteries 8.22
Capacity Ratings of Batteries 8.24
Variation in Battery Efficiency or Terminal Voltage 8.24
Points on Battery Use and Replacement 8.25
Preventive Maintenance on Batteries 8'25
Battery Questions 8.29
Battery Testing 8.31
Hydrometer Test 8.31
Load Tester 8.33
Three Minute Fast Charge Test. 8.35
Summary of Testing Conventional Batteries 8.36
Testing Maintenance-Free Batteries 8'37
Questions - Battery Testing 8.39
Charging Batteries 8.40
Charging Conventional Batteries 8.40
Charging Maintenance-Fre- Batteries 8:44
Jumper Cables 8.45
Questions - Battery Charging 8.46
Basic Starting Circuit 8.47
The Starting Motor 8.48
Switches for Starting Motors 8.50
Starting Motor Drives 8.53
Removing and Installing Starters 8.57
Questions - Starter Motors 8.58
Charging Circuits 8:59
DC Circuits 8.60
AC Circuits 8.61
Preventive Maintenance Service of Charging Systems 8.64
Questions - Charging Circuits 8.65
Ignition System 8.66
Ignition Circuit Operation 8.66
Wiring in the Primary Circuit 8.68
Ignition Coil and Condenser 8.68
Ignition Distributor 8.69
Centrifugal Advance Mechanism 8.71
Secondary Wiring 8.72
Ballast Resistor 8:73
Spark Plugs 8.73
Cam Angle (Dwell) and Basic Timing 8.75
Preventive Maintenance of Ignition Systems. 8.76
Removing and Installing Spark Plugs 8.76
Adjusting the Contact Point Gap or Cam Dwell 8.77
Use of Timing Light 8.78
Wiring Harness 8.78
Fuses 8.79

8
 Points on Fuses 8/9
Questions Ignition Circuit 8.80
Answers -- Electricity Theory 8.82
Answers Batteries 8.83
Answers Battery Testing 8-84
Answers Battery Charging 8.85
Answers Starter Motors 8.86
Answers Charging System 8'87
Answers Ignition Circuit ..8.88
Tasks Electricity 8.89

BLOCK 9 WINCHES
Winches 91
Tractor Mounted Winches. .91
Types of Single-Drum Tractor- Mounted Winches 93
Winch Brakes 9.7
Power Shift Clutches 9.10
Winch Options 9.12
Questions Tractor Mounted Winches 9.12
Preventive Maintenance Service of Tractor Mounted Winches ....... .. ...913
Scheduled Maintenance Checks 913
Winch Adjustments 9.19
Removal and Installation of Tractor Mounted Winches.... .. ..... .... ...... 9.20
Questions Maintenance and Repair of Tractor Mounted Winches. . . 9 20
Hoist Winches for Cranes. Excavators and Yarders 9 22
Cable Operation. 9.25
Basic Winch Assembly 9.26
Drum Operation 9.28
Winch Power Train 9.29
Drums and Drum Lagging 9'31
Hoist Winch Clutches Brakes and Controls .....9 33
Basic Hoist Winch Brake 9.33
Basic Hoist Winch Clutch 9.33
Expanding Air Tube. Multi-Disc Clutches 9.34
Air Tube Clutches 9.34
Magnetic Clutches 9 34
Cab Controls for Clutches aid Brakes 9 35
Hoist Winches on Hydraulic Cranes 9.35
Questions Hoist Winches 9.37
Removal and Installation of Crane.Excavator and Yarder Hoist Winches 9 38
Scheduled Maintenance Checks, Adjustments and Lubrication
on Hoist Winches 9 38
Adjustments on Contracting Band Clutch 9.38
Clutch Band Lines 918
Example Adjustment of Contracting Band Brake 9 39
Lubrication for Hoist Winches 9.40
Questions Maintenance of Hoist Winches .9.43
Wire Rope 9 44
Measuring a Wire Rope .... 9 47
Cores 9'48
Wires 9.48
Strands 9 48
Wire Rope Inspection 9.51
Points on Inspecting Wire Rope 9.51
External Rope Damage or Abuse .... 9.52
Diameter Measurement and Broken Wire Count .9.54
Inspect Drums and Sheaves 9.55

9
Lubricating Wire Rope 9.55
Cutting Wire Rope 9:56
Clamps and Sheaves 9.57
Removing and Installing Wire Rope 9.60
Attaching U-Bolts 9.62
Attaching Double Saddle Clips 9.64
Reeving Wire Rope 9.64
Questions Wire Rope 9.68
Answers Tractor Mounted Winches 9/0
Answers Maintenance and Repair of Tractor Mounted Winches 9'70
Answers Hoist Winches 9/1
Answers Maintenance of Hoist Winches 9.71
Answers Wire Rope 912
Tasks Winches, Hoists and Cables 9'73
 BLOCK

Engines

11
r
 ENGINES 7:1

BASIC INTERNAL COMBUSTION ENGINE One complete series of these events is called
a cycle. To produce sustained power the
An internal combustion engine IS basically a engine must repeat this cycle over and over
container in which a mixture of air and fuel is again.
burned. This mixture rapidly expands while 81
burns, creating a force that pushes against a An engine uses two forms of motion to trans-
piston. With the force of expanding gas acting mit energy (Figure 7-2)
on 81. the piston has the potential to perform
work. Thus an internal combustion engine reciprocating motion' up-and-down or
converts the heat energy of fuel into back-and-forth motion
mechanical work energy A simple internal rotary motion circular motion around a
combustion engine is shown in Figure 7-1 point
COMPRESSION

COMBUSTION
FUEL-AIR
MIXTURE

RECIPROCATING RECIPROCATING ROTARY

NOTION MOTION
MOTION (7-2)
X 1923
Courtesy of Jona Deere Ltd

PISTON CRANKSHAFT

ROTARY CYLINDER CONNECTING ROD

MOTION
X 13:4 (7-3) BASIC PARTS OF THE ENGINE
Courtesy of John Deere Ltd

(7.1) Using four basic parts an engine converts

Courtesy of John Deere Ltd reciprocating motion into rotary motion
(Figure 7-3). The piston and cylinder are
An engine performs the following series of mated parts. closely fitted so the piston glides
events easily in the cylinder with a minimum of
clearance at the sides There is sufficient
t Fails the cylinder with a combustible mix- space above the piston for the combustion
ture of fuel and air (intake) chamber, and the top of the cylinder is closed
by a cylinder head. The c nnecting rod trans-
2 Compresses this mixture into a smaller mits the motion the piston to the
space (compression) crankshaft. A simple cranl shaft has a section
3. Ignites the mixture and causes d to ex- offset from the centerline of the shaft so that it
pand, producing power (powel) cranks whey. the shaft is turned. The stroke of
the piston (how tar it travels in the cylinder) is
4 Removes the burned gases from the cylin- set by the throw of the crankshaft (how far it is
der (exhaust) offset).

12
7:2 ENGINES

Thus. the swing of the connecting rod and the

offset of the crankshaft convert the vertical
motion of the piston to rotary motion at the
crankshaft (Figure 7.4). This change in motion
is basically the same as that created when 00000
pedalling a bicycle. the up and down motion 00000
of your leg is changed to rotary motion at the
sprocket and wheels.
2" 00000
00000
00000
Oft
Om`-.44 ATMOSPHERIC AIR COMPRESSED AIR
--
(7.5) Courtesy of John Deere Ltd

2. Air heals when it's compressed (Figure 7-

6) The air molecules rub against each
other and produce heat. The heat aids

OFFSET
ka0 combustion because It vaporizes the fuel
and fuel burns best In a vaporized state.
CRANKSHAFT

%Alb
(7_4) HOW RECIPROCATING MOTION IS
000000
TRANSk TIED TO THE CRANKSHAFT O 00000
AS ROTARY MOTION
Courtesy of John Deere Ltd
000000
O 00000
COMBUSTION THEORY O 00000
Three basic elements aro needed to produce O 00000
heat energy in an engine: O 00000
ATMOSPHERIC AIR COMPRESSED AIR
air
(7-6) AIR HEATS WHEN COMPRESSED
fuel
Counesy of John Deere Ltd
combustion Fuel and Combustion
When fuel is mixed with air and ignited. the 1. Fuel mixes readily with air. The modern
mixture will burn It's the oxygen in the air that gasoline engine works beet when about
allows the fuel to burn, fuel can't burn without 15 parts of air are mixed with one part of
oxygen. The characteristics of air and fuel fuel (Figure 7-7).
that affect combustion are discussed below.
Air O 0
0000A (SS:i AIR
1. Air can be compressed. One cubic foot of
O 00
air can be packed into one cubic inch or
less (Figure 7-5). Since air does compress. 00 A FUEL
a large volume of it can be packed into a
cylinder to surround the fuel and help it (7-7)
burn 0 FUEL-AIR RATIO FOR
GASOLINE ENGINE

Counesy of John Deere Ltd

X 19:6

13
 ENGINES 7:3

Fuel-Air Ratio For Gasoline Engine

These parts are measured by weight, not

by volume. Since air is very light 90.000
gallons would be needed to make up :he
weight necessary to mix with 10 gallons of
fuel.
2. Fuels are volatile. That is. they vaporize at
low temperatures. The ability of a fuel to
vaporize allows each particle of fuel to
contact enough air to burn lully.
3. A fuel's physical state affects the speed at
which it will burn. i.e.. the more air that
can get at the fuel. the faster it will burn
(Figure 7-8).
Courtesy of John Deere Lid

(7-8)

V:gfOriMig
SOLID fuEL SOLID FuEl.
I.': IN CONTAINER SPREAD OUT VAPORIZED NEL

Burns lazily because air Burns more auickly Burns very quickly
only contacts the because more air because air can completely
surface fuel contacts the fuel surround the particles
of fuel
In an engine only vaporized fuel is burned.
After entering the cylinder the air fuel mixture
4. Fuel must burn quickly to give the ex- in a gasoline engine. and only the air in a
plosive force necessary for full engine diesel engine, are compressed. The amount
power. yet it can't burn too explosively or that are compressed is called the com-
It could blow up the engine. The rate of pression ratio. An 8 to 1 compression ratio is
burning can be controlled by regulating. typical for gasoline engines while a 16 to 1
ratio is common for diesels (Figure 7-9).
the volatility of the fuel
the proportion of fuel in the fuel air
mixture
the pressure and the heat of the air

Supplying, Compressing and Igniting Fuel Air

Mixtures
In gasoline engines. fuel and air are mixed
outside the cylinders in the carburetor and
manifold. the mixture is drawn into the cylin-
der by the partial vacuum created during the
piston's intake stroke. In diesel engines. there GASOLINE DIESEL
is no pre-mixing of air and luel outside the 8 TO 1 RATIO 16 TO 1 RATIO
cylinder. Air only is taken into the cylinder (7.9) COMPRESSION RATIOS COMPARED
through the intake manilold. Courtesy of John Deere Ltd

14
 7:4 ENGINES

The fuel in the compressed fuel air mixture in CHARACTERISTICS OF ENGINES

a gasoline engine is ignited by a spark plug.
In a diesel engine. as the piston nears the top Engines can be characterized or classified
of its compression stroke. fuel is injected or according to:
sprayed into the cylinder and mixes with the number of cylinders
comCressed air The fuel is then ignited by the
heat (approximately 538 C) of the denceiy arrangement of cylinders
compressed air. arrangement of valves
Figure 7 to 10 summarizes fuel combustion in number of strokes per cycle
gasoline and Mosel engines. type of cooling
type of fuel burned
These engine characteristics are discussed
FUEL-AIR below
AIR
MIXTURE
NUMBER OF CYLINDERS
The previous discussion of basic engine prin-
ciples focused on a single cylinder engine.
Single cylinder engines are used on small
equipment such as lawnmowers. Other
engines have multiple cylinders: 2. 3. 4. 5, 6, 8,
12 and 16 An even number of cylinders is
most common. Multiple cylinder engines give
a smoother more conlinuous power flow than
single cylinder engines.
Multiple cylinder engines have one common
crankshaft with all the pistons and connecting
rods connected to it (Figure 7-11).

GASOLINE (7-10) DIESEL

1 Fuel-Air Are 1 Air Only Enters Cylinder

Mixed in Carburetor 2 Air Is Compressed
2 Mixture Enters Cylinder 3 Fuel Is Sprayed In
and Is Compressed 4 FuelAir Ignites
3 Spark Ignites From Heat of Compression
The Mixture
Courtesy of Jonn Deere Ltd

Note that the higher compression ratio makes

a diesel more efficient than a gasoline engine
The higher ratio allows for a greater ex-
pansion of gases in the cylinder after com-
bustion and this results in a more powerful
stroke A consequence of the higher com-
pression ratio is that diesel engines have to
be built of sturdier. more expensive parts than
gasoline engines to withstand the greater
combustion forces A diesel's pistons. pins.
rods and cranks are beefed up. and it has
more main bearings to support the crankshaft.

15
 ENGINES 7:5

I
I
II
II II

JAIA610111)

1-6
FLYWHEEL

(7-11) CRANKSHAFT FOR A SIX-CYLINDER ENGINE

Courtesy or John Deere Ltd

e 3-4

The crankshaft is shaped so that the pistons ARRANGEMENT OF CYLINDERS

will all complete one cycle intake. com-
press:on power and exhaust wit:iin one. or in Multi-cylinder engines are made in one of
some engines two. crankshaft revolutions. three configurations (Figure 7-12):
Weights on the crankshaft balance the forces
from the rapidly moving parts within the
engine. A heavy flywheel connected to the V
rear of the crankshaft also balances or evens opposed
out the power impulses from the pistons.

V-TYPE OPPOSED

:d.
(7-12) Courtesy ot John Deere Lld

/6
7:6 ENGINES

The in-line cylinder arrangement has all the Two Stroke Cycle Engine
cylinders in a straight line above the
crakshaft; the V has two banks of cylinders In the two stroke cycle engine. the complete
arranged in a V above the crankshaft: the op- cycle of events intake, compression. power
posed has Iwo rows of horizontal cylinder. one and exhaust takes place during two piston
on either side of the crankshaft The in-line strokes. Every time the piston moves down it's
and V are the two most common cylinder a power stroke. every time it moves up it's a
arrangements found on heavy duty machines compression stroke The intake and exhaust
take place during part of the compression and
The cylinders in an engine are usually num- power strokes Figure 7-14 illustrates the
bered In-line engine cylinders are numbered cycle of events on a two stoke diesel engine.
1. 2, 3.4, etc , starting at the end of the engine
furthest from the flywheel. The cylinder num-
bering for V and opposed cylinder
arrangements varies with the manufsctuier.

VALVE ARRANGEMENT (7-14)

Another common way to classify engines is by
the arrangement of the intake and exhaust
valves, The valves can be located in diffe,rit
Positions in the cylinder head or the cylinder
block. Figure 7-13 shows four types of valve
arrangments.
CYLINDER HEAD CYLINDER HEAD

ilITAKE AND EXHAUST

BLOCK
0
BLOCK
11
I-HEAD H HEAD F-HEAD
t2 CYCLE) (7-13)
Y: 4

Courtesy of John Deere Ltd

The 1 -Head and H-Head are combined under

the name of overhead valves and are the most
common valve arrangements used today.

NUMBER OF STROKES PER CYCLE

Most engines have either a two or a four COMPRESSION

stroke cycle. The two strolte cycle engine has

two strokes of the piston. one up and one
down. during each cycle. These two strokes
occur during the one revolution of the
crankshaft and are repeated over and over
again.
The four stroke cycle engine has four strokes
of the piston. two up and two down, during
each cycle. The four strokes occur during two
revolutions of the crankshaft. Most engines POWER

today have a four stroke cycle. Courtesy of JOhn Deere Lld

17
 ENGINES 7:7

Occasionally. in this type of diesel engine. a Four Stroke Cycla Engine

blower (also called a scavenge blower) forces
air into the cylinder for the expulsion of fri four stroke cycle engines. the same four
exhaust gases and the supply of fresh air for operations occur -- intake. compression.
combustion In place of intake valves the power, and exhaust however. lour strokes of
cylinder wall contains a row of ports which the piston. two up and two down. are needed
are above the piston when it is at the bottom to complete the cycle As a result. the
of its stroke These ports admit air from the crankshaft will rotate two turns before one
blower into the cylinder when they are un- cycle is completed.
covered (during intake) Figure 7-15 shows the strokes of a lour stroke
The flow of air toward the exhaust valves cycle gasoline engine.
pushes the exhaust gases out of the cylinders
and leaves them full of clean air when the
piston again rises to cover the ports (during The intake stroke starts with the piston near
compression) At the same time. the exhaust the top and ends with it near tree bOttcen of its
valves close and the fresh air is compressed stroke. The intake valve is opened and as the
in the closed cylinder. piston moves down a low pressure is created
within the cylinder. Atmospheric pressure
As the piston nears the top of :ts compression then forces the air-fuel mixture in a gasoline
stroke. fuel is sprayed into the combustion engine. or air only in a diesel engine into the
area The heat of compression ignites the fuel cylinder.
and the resulting pressure forces the piston
down on its power stroke. The piston then un- The compression stroke begins with the
covers the intake ports. the exhaust valves piston at the bottom of the cylinder. Next the
open. and the cycle begins once more. piston rises, compressing the fuel-air mixture.
Since the intake and exhaust valves are
This entire cycle is completed in one closed. there is no escape and the mixture is
revolution of the crankshaft or two stokes of compressed to a fraction of its original
the piston. The number of pistons the engine volume.
has makes no difference, ail pistons in this
two cycle engine will fire during one
revolution of the crankshaft (7-15) FOUR STROKE CYCLE ENGINE
AIR

is. F el
(Gasoline Shown)

i_

INTAKE COMPRESSION POWER EXHAUST

Fool Air Mixture Mixture Is Compressed Compressed Mixture Is Piston On Up-Stroke
IS ()town Into By Up-Stroke Of Poston Ignited By Spook PIN Forces Horned (doses
Cy Imdel From Cor Both Intoko and Exhoust and Expanding Goes From Cylinder Through
Ingetor Through volues ore Closed. Porto Prston To Bottom Open Exhaust Vo lue
Open Info lie VOW 06 Cylinder Vogues
Sy 0own-Stroke Of Remain Closet!.
Piston CouitosY of John Deem lid

18
7:8 ENGINES

The power stroke begins when the piston The three fuel systems are discussed in detail
nears the top of its stroke and the fuel -air mix- further on in this section The chart in Figure
ture is ignited As the mixture burns and ex- 7-16 compares the performance of gasoline.
pands. it forces the piston down on its power LPG. and diesel engines
sloke The valves remain closed so that all
the force is exerted on the piston The comparisons assume that each fuel is
available at a reasonable price. Performance
The exhaust stroke begins when the piston is based on general applications which are
reaches the end of its power stroke The suited to the engine and fuel type It es also
exhaust valve is opened and the piston rises. assumed that the engines are all in good con-
pushing ow the burned gases When the dition
piston reaches the top, the exhaust valve is (7-16)
closed and the piston IS ready for a new four
stroke cycle of intake. compression power COMPARING THE ENGINES
and exhaust When the piston competes the Gasoline LPG Diesel
cycle the crankshaft will have gone around
twice Fuel Economy Fair Good Best
Hours Before
Two Cycle versus Four Cycle Engines Maintenance Fair Good Good
Weight per
It mignt be reasoned that the two cycle engine Horsepower Low
Low High
can produce twice as much power as a four
cycle engine However. this IS not quite true Cold Weather
Starting Good Fair Fair
In the !wo cycle engine, some power may be
used to drive the blower that forces the fuel- Acceleration Good Good Fair
air charge into the cylinder under pressure. Continuous
Also. the burned gases are not completely Di'ty Fair Fair Good
cleared from the cylinder. resulting in less
power per power stroke Another loss in the Lubricating On
Contamination Moderate LOwest Low
effective power stroke occurs because the
exhaust valves open earlier in a two cycle Compression
engine Ratio Low Higher Highest

The actual gain in power of a two cycle CoutteSy 01 Juhn Deere Lid
engine over a four cycle engine of the same
displacement is about 75%

TYPES OF ENGINE COOLING

Engines can also be classified according to
their cooling system There are two types of
cooling water cooled and air cooled Air
cooled systems are generally used on small
engines although one manufacturer of diesel
engines. Ouetz uses air cooling on its
engineS Water or liquid cooled is the most
common metnod of engine cooling Cooling
systems are detailed later

TYPE OF FUEL BURNED

The three most common types of engine fuel
are
gasoline
diesel
Liquid Petroleum Gas (usually
propane) (LPG)

19
 ENGINES 7:9

QUESTIONS INTRODUCTION TO 12. What are the three most common types
INTERNAL COMBUSTION ENGINE of fuel burned in internal combustion
engines?
1. An internal combustion engine converts
the energy of fuel into 13. What is the basic difference on the com-
energy that does work. bustion processes of diesel and gasoline
engines?
2. What are the three basic elements
needed to produce heat energy in an 14 Why is the compression ratio higher in a
engine? diesel engine?
3 What happens to the air in a cylinder
when it is compressed?
4. In what physical state is fuel burnt in an
engine?
5. True or False? It is the nitrogen in air
that causes fuel to burn.
6 An engine changes reciprocating motion
into _ motion to transmit
energy.
7. For an engine to Lperate. which
sequence of events must occur?
(a) intake. exhaust. compression and
power
(b) compression. intake. power and
exhaust
(c) exhaust. power. compression and
intake
(d) intake. compression. power and
exhaust
8 One complete series pi the events on th'
last question is called a
(a) stroke
(b) circle
(c) cycle
(d) stroke-cycle
9 When both intake and exhaust valves are
located in the cylinder head. the engine
is said to De a
(a) F-Head
(b) I-Head
(c) L-Head
(d) 14-Head
10 Briefly explain the basic difference be-
tween a two stroke cycle engine and a
four stroke cycle engine.
11. Engines can either be cooled
or cooled.

s. 20
7:10 ENGINES

The remainder of this block on Engines will Air cooling air passes around the engine to
discuss the five basic engine support dissipate heat.
systems: cooling. lubrication. air induction.
exhaust and fuel. Liquid Cooling water circulates around the
engine to dissipate heat.
COOLING SYSTEMS
.-.ir Cooling is used primarily on small engines
The cooling system has two functions. or aircraft as it is difficult to route air to all the
heat points of larger engines. Metal baffles.
1. To prevent overheating of the engine. ducts. and blowers are used to aid in
Overheating could burn up engine parts in distributing air to engine parts.
a short time. Some heat is needed for Liquid Cooling normally uses water as a
combustion. but a working engine
coolant. In cold weather. anti-freeze solutions
generates too much heat. The cooling are added to the water to prevent freezing.
system must carry off this excess heat.
2 To regulate engine temperature. The circulation of the coolant through the
cooling system can be followed in Figure 7-17.
Regulating the temperature allows the A water pump (8), mounted on tha engine.
engine to be maintained at the best heat draws coolant from the radiator oottom.
level for good combustion during each through the coolant inlet hose (9). The coolant
stage of operation During starting. no is then forced through the oil cooler (tG), and
cooling is necessary since the engine into the cylinder block. 1 he coolant then cir-
must be warmed up as fast as possible culate, around the cylinder bores and up into
Later. during peak operations. the engine the cylinder head water jacket. through the
must be cooled. thermostat housings (6). up through coolant
outlet noses (3) and back to the radiator (4).
TYPES OF COOLING SYSTEMS Air flow through the radiator cools the water
Two types of cooling systems are used on and dissipates heat into the air. The water
modern engines-
then recirculates into the engine to pick up
more heat.

1Thermostat RADIATOR MOUNTING AND HOSES

2Crossover Tube (COOLING SYSTEM)
3Coolant Outlet Hoses
2 3
4Radiator 1

6Deaeration Line
6Thermostat 14-busing
7Over Flow tube
8Water Pump
9Coolant Inlet Hose
10Engine Oil Cooler
11Pressure Renef Valve
12Water Filter (If Used)
13Drain Cock

Courtesy of Terex Division of

General Motors Corporation

(7-17) 1\3 12

21
 ENGINES 7:11

COOLING SYSTEM COMPONENTS

0
Blocks, Heads and Manifolds
The engine cyl,nder block and head contain a
number of connecting passages to allow
coolant to flow completely around all of the AO
cylinders. combustion chambers and valves.
Together these passages make up the water
el; c %

jacket (Figure 7-18)

twiA6Afr,.
W .1vArAr.
41.

CYLINDER liEAD
VALVE
WATER
JACKETS CYLINDER

PISTON
(7-19) fIEMOvING THE CYLINDER HEAD
CYLINDER
BLOCK Counesy of John Deere Ltd
Radiator
The radiator is the heat exchanger for the
cooling system (Figure 7-20). It consists of a
top tank. a bottom tank and a finned core sec-
tion. The bottom tank is equipped with a drain
at its lowest point. The tanks may be soldered
to the core section like the one shown below.
or the tanks and side pieces may be bolted to
the core sections. Radiators used for large
Courtesy of John Deere Ltd engines and machines generally have bolted-
(7-18) IN-LINE BLOCK on tanks.
Coultesy of J i Case
The water jacket holds only a small amount of
coolant This small amount allows for rapid
warm up while the thermostat is closed when TOP TANK
first starting the engine. but is still enough to
provide efficient cooling to all the vital areas
when the thermostat is open and the engine
warm
Note the holes in the cylinder block and cylin-
der head in Figure 7-19 Not all. but many. of
these holes are water passages

As well as the internal connecting passages of

the water jacket. some engines use external
connecting passages called water manifolds.
They are bolted onto the outside of the engine CORE
by a flange mount and have a gasket between
the two mating surtaces. Water manifolds are
used, for example. between cylinder heads
when an engine has multiple cylinder heads. BOTTOM
or between the oil cooler and engine block. TANK
(7-20)
TYPICAL RADIATOR

22
 7:12 ENGINES

Two types of radiator cores are illustrated in coolant is transferred to the fins From the fins
Figure 7-21. a tube and fin core and a cellular the heat is radiated out into the air currents
core Variations on the tube and fin core are that pass through the core and is carried
the most commonly used in radiators today. away

WATER Water Puma

PASSAGE TUBE
The water pump is said to be the heart of the
cooling system: it must circulate the water
throughout the cooling system (Figure 7-22).
The pump is located at the front of the engine
and is generally driven directly or indirectly by
V belts attached to the crankshaft pulley. The
pump shaft is mounted on lubricated and
sealed anti-friction bearings. The impeller. the
AIR part of the pump that propels the coolant. is
(7-21) TUBE and FIN-TYPE pressed on the inner end of the shaft. The size
RADIATOR CORES and design e the impeller will depend on the
Courtesy of John Deere Ltd coolant flow requirements of a particular
WATER engine.
PASSAGE
Most cooling systems use a centrifugal pump
Similar to the one in Figure 7-23.

SPRING RETAINER

ELBOW t BALL BEARING

HOUSING

IMPELLER

AIR COVER

(7-21) CELLULAR-TYPE FAN PULLEY

RADIATOR CORE
FAN HUB
Courtesy of John Deere Ltd
is+

Radiators work on the principles of con- SEAL

vection (circulation of the coolant) and

radiation (sending heal in waves into the air). GASKET
Flow created by the water pump and by ther- X :: 1, 0
(7-23) WATER PUMP DISASSEMBLED
mal syphon action carries heated coolant
from the engine to the radiator. The heated Courtesy 01 John Deere Ltd
coolant enters the radiator by the upper
radiator connection hose. As the coolant
flows down through the core. heat from the

RADIATOI

WATER
PUMP BLOCK

(7-22) WATER PUMP Courtesy of John Deere Ltd

23
 ENGINES 7:13

Thermostats Thermostats are made in a variety of tem-

perature ranges to meet various working con-
The thermostat provides automatic control of ditions. A high temperature thermostat has
engine temperature to get the best per- some advantages. High-temperature ther-
formance from an engine The thermostat is mostats. which open at 82.0 (180 F) or more.
basically a temperature sensing device and a improve engine operation and reduce crank-
valve. The temperature of the coolant acts on case sludging and corrosive wear of engine
the heat sensory unit which opens and closes parts. An engine operating above 82'C (180 F)
the valve creating a flow of coolant that main- is hot enough to:
tains the desired engine temperature. Only a
small part of the engine's cooling capacity is improve combustion
required under light lc Js, even during warm burn impurities out of the oil in the
weather. During warm-up the thermostat crankcase
remains closed; by means of a bypass the
water pump circulates coolant through only thin the oil to provide good lubrication
the engine water jacket. The engine quickly Caution; Do not use low-boiling-point
warms up to its operating temperature before alcohol or methanol anti-freeze
the thermostat opens. When the thermostat with high-temperature thermostats.
opens. hot coolant flows from the engine to
the radiator and back to the engine (Figure 7- Overheating may so damage a thermostat that
24). the valve won't function properly. Rust can
also interfere with thermostat operation. If a
thermostat is not running properly the engine
BYPASS will run too hot or too cold. The following
TO RADIATOR practices should be observed with ther-
mostats:
Always keep a thermostat in good
working condition.
Never operate the engine without a
it Coolant thermostat.
Cold
Always use the thermostat (design)
THERMOSTAT specified for the make and model of the
CLOSED engine being used.)

COOLANT Fans, Belts and Drives

THERMOSTAT HOT
OPEN The purpose of the engine fan is to create a
draft of air through the radiator. When the
Ylr (7-24) COOLING SYSTEM THERMOSTAT engine runs. the fan pulls or pushes air across
Courtesy 01 John Deere Ltd the radiator core to cool the liquid in the
radiator. The ideal location of the fan is ap-
The thermostat is located between the coolant proximately 2'rt inches from the radiator core.
outlet of the cylinder head and the top tank of The size and number of blades on the fan will
the radiator The exact location will vary from vary depending on the cooling requirements
.engine to engine. Large engines sometimes of the machine.
use two thermostats to reduce the restriction
of water flow that can be caused by one ther- Fans on smaller engines are bolted to a flange
mostat. on the water pump shaft. Larger engines have
the tan mounted on a separate fan hub; this
The two most common types of thermostats fan is generally driven by a belt(s) from the
are engine crankshaft. as seen in Figure 7-25.
1. Wax pellet type wax pellet expands
with increased temperature to open the
valve.
2. Bellows type gas inside a bellows ex-
pands when heated Causing the valve to
open.

24
7:14 ENGINES

./
FAN HUB
ADJUSTING BOLT tr!-- -

(7.25)

CRANKSHAFT
Conres. of Generm Movers Corpotanon
BELTS

Fans can be either suction or blower fans. The Ian can be fixed drive or thermostatically-
depending upon the design of the cooling operated drive The fixed drive fan turns con-
system Suction fans (Figure 7-26) pull air tinuously as the crankshaft turns. the ther-
through the radiator and push it over the mostatic drive fan is temperature controlled
engine The suction design permits the use of and operates oily when it is required The
a smaller fan and rldiator than is requited for thermostat drive has the advantage of not
blower fans Sue .n tans are used when wasting engine horsepower to turn the fan
machine mot' aids air movement through when it isn't needed.
the radiator such as on a truck
Some machines have a shrouding around the
fan (Figures 7-27 and 7-28). Shrouding in-
creases fan efficiency by controlling or direc-
ting air flow through the radiator. Fan shrouds
fit close to the fan blades to prevent recir-
SUCTION culation of air at the blade tips. A blower fan
FAN IS usually set 1/3 into the shroud and a suction
fan is usually set 2/3 into the shroud.
Counesy of
John Deere Ltd FAN SHROUD
(7-26)
6.

Blower fans (Figure 7-26) pull air across the

engine, then push it through the radiator. They
are used in slow-moving machines and on
equipment where harmful materials might be
drawn into the radiator by a suction fan.
ti
jt

yt

BLOWER r'
FAN
Fan Shroud.
(7-27)
Counesy of Caterpillar Tractor Co
(7 -26)

Counesy of John Deere Ltd

25
 ENGINES 7:15
RADIATOR

Courtesy of Font MOlOr Company

Because there is a definite fit to a belt and

-N
LOWER HOSE pulley. replace belts Only with the type
recommended in the service manual.
Belts that drive fans are called V belts be- Small engines (on automobiles and light
cause of their V shape A belt's ability to trucks) generally use one belt and this belt
transmit power from the crankshaft depends performs three lobs drives the water pump,
on. the fan. and the alternator Larger gasoline
1 The tension holding the belt to the pulley and diesel engines use multiple belts In mat-
Belt tenon is a very important service ched sets that may drive just the fan or they
point and will be covered later. may drive all three: the fan. water pump ?r"l
alternator.
2 Friction between the belt and pulleys Hoses and Clamps
Belts should run dry. Oil on belts causes
them to slip. and so any oil teaks in the Flexible hoses connect the radiator to the
area of the belts must be quickly repaired engine. Flexible hose is used rather than rigid
pipe because the hose stands up better under
3 Arc of contact or wrap between the belt vibration. Radiator hose slide fits over the
and pulleys Wrap is built into a belt and radiator and engine connections and is
pulley when manufactured Figure 7-29 secured with a compression clamp (Figure 7-
illustrates how a V-belt runs in a sheave 30). CAP
both at rest and under load.
(7-30)

RADIATOR ROSE

\
UPPER 8260

CLAMP

(7-29)
---vt----
UNDER LOAD VIA DUI MA HOSE LOWER

Courtesy of John Deere Ltd

RADIATOR ASSEMBLY MS

Courtesy of Ford Motor COmdany

7:16 ENGINES

Various types of hose are mat e'

1 Straight hoses will collapse if bent. and SHUTTERSTAT
so is only used between two in-line fit- --..
tings. Available in various I.D sizes and in
three or four foot lengths to be cut as
desired.
2 Universal flex-hose has spiral wire
moulded into the hose to prevent it from
collapsing when installed where a curved AIR
hose is required It too comes in various CYLINDE-
I 0 sizes and in three or four foot lengths
to be cut as desired.
3 Mouldit hoses are manufactured to the
correct size. length and angle to fit a
specific location.
As durable as hoses are. they still have weak
points Radiator hoses can be damaged by hot
air or over heated water and 7.,snera:ly will
/ SHUTTER
deteriorate over long period: , age. Two
..1

common types of hose damage are

1 Hardening or cracking which destroys
hose flexibility. causing leakage and
allowing small pieces of rubber from the
hose's inner liner to clog the radiator. (7-31) AIR - OPERATED RADIATOR SHUTTER
ASSEMBLY GAS ENGINE
2. Softening and swelling which deteriorates Courtesy of Ford Motor Company
the hose lining and can cause the hose to Q101 5 -A
rupture or break
Shutter action depends upon engine tem-
Radiator Shutters peratures as sensed by the shutterstat. The
shutterstat is located so that it responds to
Shutters help to maintain optimum engine coolant temperature. Until coolant tem-
temperature by controlling air flow through perature rises to approximately 185 F (85 C).
the radiator the shutters remain closed. When the shut-
terstat operating temperature is reached. ther-
The system consists of (Figure 7-31)-
mostatic action shuts off air supply to the air
t the shutter cylinder and simultaneously exhausts air
pressure from the cylinder. Shutter spring ac-
2 shutter control bar tion then opens the shutters. Note that the
3 air cylinder shutters don't partially open; they are either
fully open or fully closed.
4 shutterstat (temperature control valve)
Coolant Filter
Some engines use a filter in the cooling
system The coolant filter (Figure 7.32) softens
the water and removes dirt As a result. the
cooling system dissipates heat better and its
working parts wear longer

27
 ENGINES 7:17

Different types of coolant filters are available

One factor that has a bearing on filter type is
the kind o. :nti-freeze used in the cooling
system. r, Ite:s *61 anti-freezes must be com-
patibici.

COOLANT
Coolant Rewire Items
A suitable coolant solution must meet the
following i.a.;..: tequirements:
provide for adequate heat transfer
provide a corrosion-resistant en-
vironment within the cooling system
prevent formation of scale or sludge
deposits in the cooling system
be compatible with the cooling system
hose and seal materials
provide adequate freeze protection
(7-32) COOLANT FILTER during cold weather operation.
Courtesy 01 John Deem Ltd
When freeze protection is not required a
solution of suitable water plus corrosion
The coolant filter has a replaceable element. It inhibitors (assuming no coolant filter) will
also has a sump at the bottom of the filter satisfy these requirements When freeze
where dirt settles. The sump drain plug should protection is required a solution of suitable
be opened periodically to dispose of the water plus permanent anti-freeze (which con-
sediment. tains corrosion inhibitors) will be a satisfac-
tory coolant.
Instead of replaceable element coolant filters.
some manufacturers use spin-on filters that
are thrown a. ray after the engine has gone a The Need For Corrosion Inhibitors
certain num er of miles For servicing their Any water. whether of drinking quality or not.
vehicle these manufacturers supply a set of will produce corrosion in the cooling system
spin-on-throw-away filters for oil. fuel and Also. scale deposits may form on the internal
coolant They reason that the coolant filter is surfaces of the cooling system due to the
less likely to be overlooked (which does hap- mineral content of the water. Therefore. water
pen with replaceable element filters) if it is in- used as a cooiant, mast be properly treated
cluded with the other filters with inhibitors to protect the metallic surfaces
Chemicals in the filler element and resistor of the cooling system against corrosion and
plates soften the water by removing scale deposits.
corrosives The softer water helps to keep the Figure 7-33 illustrates the harm done by
radiator and water Jackets free of scale mineral deposits. cast iron with mineral
Another chemical in the filter dissolves into deposit withholds its heat rather than readily
the water to alkalize it just enough to prevent transferring it to the coolant.
acid corrosion of the metal parts. Rust
inhibitors are also placed in the element
which dissolve into the water and form a rust-
protective film on the metal surfaces of the
cooling system
The filter shown in Figure 7-32 is a bypass
type If it clogs. all water will bypass the filter
and go straight to the engine.

28
 ENGINES
changing the coolant and adoing a new anti-
HEAT TRANSFER CAPACITY
freeze-water solution at certain hour or
mileage intervals.
As was mentioned earlier. coolant filters
which are found on some machines have
corrosive inhibiting chemicals in their filtering
114 material. Additional inhibitors are not needed
CAST
and shouldn't be added. Cooling systems
IRON which have a filter and need permanent anti-
freeze (which has corrosion inhibitors) will
use a special type of filtering element.

41\_I/16-
MINERAL DEPOSIT

I CAST IRON PLUS 1116- MINERAL DEPOSIT

4 1 /4 CAST IRON IN HEAT TRANSFERARIUTY

(7-33)
Courtesy of Detroit Diesel Division of
General Motors Corporation

All inhibitors become depleted through nor-

mal operation, and additional inhibitors (or
anti-freeze) must be added to the coolant at
prescribed intervals to maintain original
strengths. Also. after a scheduled amoun. of
hours or miles the coolant should be com-
pletely drained and replenished. Always
follow the manufacturer's recommendations
on inhibitor and anti-freeze usage.

Anti-freeze
When freeze protection is required. a per-
manent anti-freeze must be used An inhibitor
system is included in this type of anti-freeze.
and no additional inhibitors are required if. on
initial fill a minimum anti-freeze concentration
of 30% by volume is used Solutions of less
than 30% concentration do not provide suf-
ficient corrosion protection. Conversely, con-
centrations over 67% adversely affect freeze
protection and heat transfer rates.
There are two kinds of anti-freeze: ethylene
glycol base anti-freeze and methoxy propanol
base anti-freeze Ethylene glycol is most com-
mon The methoxy propanol base anti-freeze
is incompatible with the seals used in some
cooling systems and should not be used
unless recommended by the manufacturer.
The inhibitors in permanent anti-freeze should
be replenished at approximately 500 hours or
20.000 mile intervals. Commercially available
inhibitors may be used to restore inhibitor
strengths in anit-freeze solutions. However.
most manufacturer's will recommend 29
 ENGINES 7:19

Summary of Coolant Recommendations

1. Always use a properly inhibited coolant
and maintari the inhibitor strength.
P
A
2. Do not use soluble oil as an inhibitor.
3. Always follow the manufacturer's recom-
mendations on inhibitor and anti-freeze
usage and handling.
4. If freeze protection is required, always
use a permanent anti-freeze.
5. To keep up inhibitcr strength in anti-
freeze add a recommended non-
chromate inhibitor or drain the system
and change the anti-freeze.
6. Do not use a chromate inhibitor with per-
manent anti-freeze.
7. Do not use methoxy propanol base anti-
freeze unless recommended by the
manufacturer.
8. Do not mix ethylene glycol base anti-
freeze with methoxy propanol base anti-
freeze in the cooling system.
9. Do not use an anti-freeze containing
sealer additives.
10. Use extreme care when removing the
radiator pressure control cap.

30
 7:20 ENGINES

PREVENTIVE MAINTENANCE SERVICE ON plugged with rust. White. rusty. or colored

COOLING SYSTEMS stains indicate previous rldiator leakage. If
water cr an alcohol-based anti-freeze is used
4 The cooling system should be -isually in- these spots may be dry because such
spected during the daily walk around check. coolants evaporate quickly. If the stains are
and (luring scheduled maintenance on the damp it's because an ethylene glycol anti-
system. Minor problems should be im- freeze was used and it doesn't evaporate.
mediately repaired. and major ones should be
reported Inspection checks on the cooling Always seal a radiator leak before installrig
system can be found in the service manual anti-freeze coolant. Depending on size and
and should include the following. number. radiator leaks can be repaired with a
sealing compound. by soldering. or they may
1 Check the coolant level and add water if have to be tended to by a radiator repair shop.
low. Note that sealing compounds are not recom-
(a) System without reserve tanks. mended by some manufacturers because:
remove the radiator cap and check 1. they aren't a permanent repair.
the coolant level. Caution: If the
system is hot. it contains pressure. 2. they can ultimately cause plugging of the
Removing the radiator cap when the radiator.
coolant is hot could cause injury.
Wait until the coolant cools down. Other Radiator Checks
and then slowly remove the cap.
Hissing after a slight turn of the cap 1. Check radiator baffles (Figure 7-34).
will indicate the system is still under Missing or damaged baffils can allow
pressure and too hot tr. open. enough air recirculation to cause
overheating.
(b) Cooling system with reserve tanks:
check the coolant level by checking BAFFLES
the level of the see-through plastic
reserve tank or by removing the cap.
2. Inspect for ieaks. Leaks can occur in the
radiator, on the outside of the engine
waterjacket. in hoses and at hose con-
nections. Internal water leaks can also oc-
cur. but they won't be dealt with here.
Leakage is the most rommon problem in a
cooling system and can increase during
winter due to metal shrinkage. Air
pressure leakage testers can be helpful in
locating external leaks. Leaks are easiest
found when the system is cold.
Minor teaks can be repaired with a sealing
compound. However, only practical ex-
perience enables a serviceman to tell if a
leak can be corrected with a sealing
solution. Follow instructions when using
sealing solutions: some react chemically
with anti-freeze and rust inhibitors and
may seriously affect coolant performance.
Radiator Leakage
Most radiator leakage is due to cracking of
soldered joints caused by engine vibration.
frame vibration, and cooling system pressure.
Carefully examine radiator for leaks before
and after cleaning. Some leakage points may (7-34)
have gone undetected because they were Courtesy of Cater Pular Tractor Co

31
 ENGINES 7:21

2. Check for radiator plugging. The major

cause of reduced air flow is the ac-
cumulation of foreign material in the
74ii1 RPlianift
radiator core air passages (Figure 7-35). In
land clearing. sanitary land fill and other
jobs where trash is present, leaves, weeds
and other debris are drawn into the
radiator core. As the core becomes
plugged. the effective cooling area is
reduced and heat transfer rapidly
decreases. .
Courtesy of Catercatiar Tractor Co
,z...

In

If ...Ma.

(7-36) CLEANING THE RADIATOR CORE

Courtesy of Caterpritar Tractor Co

External Waterjacket Leakage

Inspect the engine cylinder block while the
-.....
engine is running both before and after it gets
hot. Leakage of the engine block is
aggravated by pressure in the cooling system
and temperature changes of the metal. Small
leaks may appear only as rust. corrosion. or
(7-35) DIRT CAKED IN CORE FINS stains due to evaporation.
PLUGGED RADIATOR CORE
Other Leakage Areas
Keep the radiator clean and free of dirt Watch for leaks at these trouble spots'
and trash A quick visual observation
usually won't detect core plugging. A 1. Core-Hole or Frost Plugs: Remove the old
close inspection is necessary. Check the plug then clean the plug seat and coat it
radiator core area outside the an circle. with a sealing compound. Drive a new
The core is usually free of plugging within plug into place with the proper tool
the fan circle. but a close look often 2. Gaskets: Tighten the joint or install a new
reveals extensive plugging in the outer gasket. Use a sealing compound when
core areas. An air flow meter can be used
required.
to measure the flow of air through the
radiator and thus pinpoint plugged areas 3. Stud Bolts and Cap Screws Apply sealing
compound to threads.
The radiator core can be cleaned with
water or air pressure (Figure 7-36). 4. Check for leaks in hose lengths and at
hose clamps. Also check for hose
deterioration (Figure 7-37).
Cooling systems are constantly expanding
and contracting as the engine starts. runs
and shuts down. Owing to such variations
in temperature. clamps can loosen and
the hose material can deteriorate.

32
 ENGINES

To be ^ale repua.se hoses often enough so that

they are always pliable and able to pass
coolant without leakage. When replacing
hoses:
1. Use the best quality hose available.
2. If universal flex hose is used. allow
enough hose for movement. but not so
rruch that buckling or wrinkling occurs.
3. Straight hoe must only be Lsed when
connections are in-line.
4 lViLuided hoses must be of the correct
(7-37) DAMAGED HOSES shape and length.
Courtesy of John Deere Lid
5. Clean the pipe connections and apply a
Hoses and clamps should be examined at thin layer of non-hardening sealing
least twice a year. Check the outside of compound when installing hoses (Figure
hoses for 7-39).

(a) hardening. cracking

(b) softening. swelling
Cracked or swollen hoses should be
replaced immediately. Also check the in-
side of hoses for
(a) corrosion of any reinforcing springs.
(b) material failure. Hoses can
deteriorate en the inside and still ap- Sedog
pear all right on the outside (Figure Compound
7-38).

(7-39) SEAL THE CONNECTIONS

Courtesy of John Deere Lid

Locate the hose clamps properly over the con-

nections as shown in Figure 7-40 to provide a
secure fastening. An improperly installed
hose (1) will be blown off by the pressurized
cooling system or (2) will allow air to be drawn
into the inlet side of the pump. causing
aeration of the coolant which is very harmful
to the engine.

X 1761
(7.38) INTERIOR OF DAMAGED HOSE
Courtesy of John Deere Ltd
(7-40)
TIGHTEN HOSE CLAMPS SECURELY
Courtesy of Jahn Deere Lld

33
 ENGINES 7:23

CHANGING THE COOLING FILTER These points are extremely important, For
example. you can imagine what would happen
Cooling filters should be changed at the time if the valves were not opened.
intervals stated in the service manuals. A
typical maintenance procedure is given Sometimes the filter may be serviced when
below. the complete cooling system is drained and
flushed. When installing new coolant remem-
Cooling Filter Service ber the following: never add rust inhibitor to a
cooling system that has a water filter. The
1 Check the condition of the electro- filter contains a corrosion inhibitor
chemical plates. 4 and 6 in Figure 7-41. af-
ter every 500 hours of operation. if the Testing Anti-freeze
plates are rusted. pitted or corroded. they The strength of anti-freeze solution must be
should be cleaned with steel wool. and sufficient to prevent freezing at the lowest
then rinsed in cleaning solvent and dried temperature expected. A number of testers
with filtered, compressed air. When the are made to check the strength of anti-freeze
plates are badly deteriorated. install new but a hydrometer is the most common one
ones. (Figure 7-42). The hydrometer works on the
principle of a float in a sight glass rising to a
level that indicates the strength of the anti-
freeze.
RUBBER-4.
BALL

I Cent 4414
tewte
Co** Cuket
4 9**9 Mt*
I 0.44494
Lowtr 4744
FLOAT
Spine
'mot S.4
471.

1 Cover Bolt 6 Lower Plate

2 Cover 7 Spring
3 Cover Gasket 8 Filler Body REFERENCE
4 Upper Plate 9 Plug SCALE
5 Element
t7-41) WATER FILTER COMPONENTS
Courtesy of Genera! Motors Corporaiion

2. The sump at the bottom of the housing (8)

should be drained and cleaned out every
500 hours.
11 a
3. Change the filter element (5) every 500
hours (see Manual for Procedures).
After the filter has been reassembled and in- (7-42)
stalled. check the following points: Courtesy of
Ford Motor Company
1. Make sure the inlet and outlet shut-off
valves are open
To use the hydrometer. insert the hydrometer.,
2. Check all hoses. fittings and connections rubber hose into the coolant at the top of the
for leaks. radiator. Squeeze the rubber ball of the
hydrometer to draw up the coolant info the
3. Check the coolant level in the radiator sight glass. The float will rise to a ocrtain
and replenish as neccesary to com- level. Compare this level to a reference scale
pensate for losses during cooler ser- to determine the strength of the anti-freeze
vicing. solution.

34
7:24 ENGINES

BELTS CHIPPED

Belts have to be checked for their condition. BENT

alignment and tension

Belt Condition
Belts are not meant to ride on the ' Atom of
the groove When they do, they heat check
and crack (Figure 7-43) or grow hard and
polished A heal damaged belt indicates that 1
either its badly worn. forcing it to ride too low
In the sheave. or that the sheave is dished out
(Figure 7-44).

(7-44) DAMAGED SHEAVES

Counesy of John Deere Ltd
Other points on belt condition:
-- A tear on the outside cover could be
caused by something interfering with
the belt. Ticking sounds when the belt
is running may indicate interference.

HEAT CHECKED A belt that has operated while rolled

over in the sheave groove is probably
damaged. Replace it.
Store belts in a cool. dry place. If
stored on a machine. relieve tension on
'JO the belts.
17-431 BELT RUINED BY TOO MUCH HEAT Belt Alignment
Courtesy of John Deere Ltd
Misalignment soon causes a good belt to sail.
In addition to heat. grease and oil can also Misalignment usually occurs when the mcun-
ruin drive belts II oil or grease is allowed to ting for the component that the belt is driving
soak into a belt. d can soften. swell and comes loose or has been improperly installed
generally deteriorate very rapidly. Note that Belt alignment can be checked by lining up a
08: resistant belts are available for certain cord or straight edge on the aide of the two
engine locations that are unavoidably greasy pulleys. as shown in Figure 7-45 Make at
or oily. When oil or grease IS round on a belt. least two checks. 180 apart
wipe it off with a clean cloth dampened with a
detergent solution. Then dry the belt with a CORD OR STRAIGHTEDGE
clean dry cloth.
CAUTION: Never try to clean a belt while it
is operating.
While inspecting the belts. the condition of t
the pulleys or sheaves should be checked.
Examine pulleys for chips. cracks. bent CORRECT ALIGNMENT
sidewalls. rust. corrosion or other damage
(Figure 7-44). Damaged sheaves cause rap*
belt wear and should be repaired or replaced
immediately

INCORRECT ALIGNMENT A.25118

17-45) PULLEY ALIGNMENT

Courtesy 01 General Motors Corporation
35
 ENGINES 7:26

Belt Tension and Adjustment The chart in Figure 7-48 shows the
amount of deflection different size belts
To carry their full load. drive belts must grip should have If a belt deflects 1/8 of an
the entire area of contact with the pulley Im- inch too much or too little, readjust it.
properly adjusted bells can damage the
pulleys Loose belts undergo unnecessary 17-48)
wear: they can slip. tear. burn or grab and
snap. Belts that are too tight. can also cause
problems They can damage the engine by Table 2: Fan Belt Tension
over-loading the crankshaft. crankshaft
bearings. and accessories or accessory Belt Width Deflection Per ft.
bearings. Also. excessrde tension on a belt Inch (mm) of Span Inch (mm)
will stretch and weaken it.
1/2 (12.700) 13/32 (10.3187)
To get maximum life and performance from a 11/16 (17.4625) 13/32 (10.3187)
bell it must be run at the correct tension. Belt 3/4 (19.0500) 7/16 (11.1125)
tension can be checked by: 7/8 (22.2250) 1/2 (12.7000)
1 (25.4000) 9/16 (14.2875)
1. A belt tension gauge. Markings on the
gauge will indicate correct or incorrect Courtesy of Cummins Engine Co
tension (Figure 7-46).
The gauge is the most accurate method to
check belt tensicn but the deflection
method is very reliable too.
Figures 7-49. 7-50 and 7-51 show three
types of belt adjusting methods using
V-BELT TENSION either slotted or elongated holes. Ad-
GAUGE justing a belt requires moving one of the
pulleys away from the other if the belt is
too loose. or vice versa, closer to the other
if the belt is too tight.

T.9964

(7-46) Courtesy 01 General Motors Corporation

2. Deflecting the belt (Figure 7-47):

X 1440 'e
(7-49) ADJUSTING BOLT IS IN
A SLOTTED BRACKET
(Gasoline Engine)
Courtesy of John Deere Ltd

Colidesy of Cummins Engine Company

36
7:26 ENGINES

ADIUSTING BOLT
*
LOCK NUT;

a
o
`-'

(7-50)

C ci
ADJUSTING BOLT
(Diesel Engtne)

/7 Courtesy of General Motors Corporation

If

ADJUSTING BOLT

BR CKET

'V

P
4-F

l'..:MOUNT1Nte
.::al
ROLTS
(7-51)

ADJUSTING BOLT IN
sik ELONGATED HOLE
(Diesel Engine)

SUPPORT
SSEMBLY

- ' .r't
16,
-

A.74416
Courtesy of General Motors Corporation

37
 ENGINES 7:27

Some belt-pulley systems use a third WRONG!

pulley called an idler which is moved to NEVER FORCE
adjust the belt tension (Figure 7-52). 'BELT ON SHEAVE'

IDLER PULLEY IDLER

ON LOCATED
SLACK SIDE DRIVE NEAR
OF DRIVEN
DRIVE
DRIVE SHEAVE
(PREFERRED)
'`.40-k
DRIVE DRIVEN .
r
(7 -52) Courtesy 01 John Deere Ltd A 110,04
0.4stA

(7-53)
IDLER PULLEY
IDLER NEVER FORCE A V-BELT ONTO A SHEAVE
ON
DRIVE LOCATED
TIGHT SIDE DRIVEN NEAR Courtesy 01 John Deere LId
OF
DRIVEN
DRIVE
(ACCEPTABLE) SHEAVE
3. Never attempt to check or adjust belts
while they are running.
4. V-belts stretch most during their first 24
hours of operation. Check the tension of a
new belt after it has run for a few shifts.
An Idler pulley can be used on both a con-
tinuous and an intermittent drive fan For 5. Never attempt to correct belt slippage by
continuous drive the idler IS adjusted in a using a belt dressing. If belts slip even
set position For intermittent drive the idler when properly tensioned. check for
is moved in to apply tension and start the overload. worn sheave.' grooves. oil or
fan. and out to slacken the tension and grease on belts. or seized bearings.
stop it The idler on the intermittent fan is
operated by a temperature controlled air 6. Note that more fan belts fail from being
cylinder. too loose than from being too tight.
However. don't overtighten belts: you'll
damage the drive component's bearings.
Good Practices When Installing and
Adjusting Belts
1. When replacing dual or triple running
drive belts. replace the complete set of
belts at the same time. Uneven operation
would result from running a new belt with
worn ones. Install them in the sets sup-
plied by the manufacturer. Never combine
belts from different sets.
2. Never pry a V-belt or force it into the
sheave groove. You can damage both the
belt and the drive component. Loosen the
lightener before installing the belt- (Figure
7-53).
7:28 ENGINES

QUESTIONS COOLING SYSTEM 14. True or False? Any water. whether of

drinking quality or not. will produce a
1 What are the two basic purposes of the corrosive environment in the cooling
cooling system? system. Thus the need for
2. True or False? In a liquid cooled system
the coolant flows into the bottom of the
radiator and out through the top. 15 On an engine equipped with a coolant
filter and using anti-freeze, what
3 What is the purpose of having the water precaution must be taken when
Jackets hold only a small amount of changing the filter?
coolant?
16. What is the most common problem with a
4 The radiator is a _ cooling system?
for the cooling system.
17. Leaks are easiest found when the system
5 Radiators work on the principle of is
(a) currents 18. Give two reasons why some manufac-
(b) convention turers do not recommend sealing com-
pounds to fix radiator leakage.
(c) convection
(d) circulation 19. What is the major cause of air flow
restriction in a radiator and how can it be
6 What is the function of the water pump? improved?
7 Engine temperature is automatically con- 20. What is the obvious sign of a hose that is
trolled by the use of a deteriorated?
21. List the three things belts should be
8 True or False? Thermostats that operate checked for during a P.M. of the cooling
at 180'F or more improve engine system.
operation and reduce both crankcase
sludging and corrosive wear of engine 22 List the three important checks that
parts. should be made after installing a new
water filter element.
9. On what type of machines are blower
fans used rather than suction fans? What 23 The strength of the anti-freeze solution is
is the reason? checked with a:
10. Shrouding is used around a fan to: (a) water meter
(b) ammeter
(a) simply protect the fan blades.
(c) hydrometer
(b) to increase fan efficiency
(d) any of the above
(c) quieten fan operation
(d) make it look neater
24. True or False? A V-belt is designed to
ride on the sides and bottom of the
11. True or False? All belts ht the same just pulley.
the lengths are different.
25. A good maintenance practice for V-belts
12. Radiator shutters are: on a vehicle that is to be stored for a
period of time is to:
(a) closed by spring pressure and
opened by air (a' adjust it for the correct tension
,..., closed by spring pressure and
(b) (b) relieve all belt tension
opened by spring pressure (c) remove the belt entirely
(c) closed by air pressure and opened (d) cover the belt to protect it
by air pressure
(d) closed by air pressure and opened
by spring pressure
13. What is the purpose of the water filler?

39
 ENGINES 7:29

26. When replacing dual or triple drive belts

the recommended practice is to:
(a) replace all as a set
(b) replace only the worn one(s)
(c) remove the worn one(s) and run the
other(s) until they need replacing
27 Referring to the fan belt tension chart,
find out how much a 3/4 inch belt with a
span of 11/2 feet should deflect.

40
 7:30 ENGINES

LUBRICATION SYSTEM The basic lubrication system used on today's

engines is called a full pressure system. Full
The lubrication system is another one of the pressure means that oil is delivered under
live support systems common to all engines pressure created by the oil pump to all the
The lubrication system does the following vital lubrication areas of the engine Figure 7-
jots for the engine (Figure 7-54). 55 shows a full pressure system and some of
the areas that it must serve.
1 Reduces fr.ctirn between moving parts.
2. Absorbs and dissipates heat.
3 Seals the piston rings and cylinder walls.
4 Cleans and flushes moving parts
5. Helps deaden the noise of the engine.

2 OIL COOLS
MOVING PARTS

1 OIL FILM
REDUCES
FRICTION
3 OIL HELPS THE
RINGS TO SEAL
AND WEAR

(7-54)
WHAT AN ENGINE
OIL MUST DO

Courtesy 0 John Deere Lid

DEADENS NOISE
X:Sae 4 OIL CLEANSES THE PARTS
TAPPET PISTON
CAMSHAFT LEVER SHAFT PIN BEARING
BEARINGS

(7-55)
MAIN
CIL
GALLERY

Courtesy 01 JOhn Deere Ltd

CRANKSHAFT OIL PUMP
AND FILTERS
MAIN BEARINGS

41
 ENGINES 7:31

LUBRICATION SYSTEM COMPONENTS

1. Oil pump and relief valve.
2 Oil Sump usually referred to as Engine
Oil Pan.
3. Filter(s)
4. Oil Cooler.
5. Pressure Differential Valves for coolers
and filters.
6. Breathers and vents.

Oil Pump
(7-56)
The oil pump is a positive displacement gear
pump which can be mounted internally in the SURFACE FILTER DEPTH FILTER
sump or externally on the engine block. Oil Courtesy 0 John Deere Ltd
pumps are driven either by the crankshaft or
the camshaft or by the timing gear train. The
pump must distribute oil under pressure Surface Filters have a single surface that cat-
throughout the lubrication system Oil ches and removes dirt particles larger than
pressure varies in different engines usually the holes in the filter. Dirt is strained or
from 20 P.S.I. to 65 PSI.. although some will sheared from the oil and stopped outside the
go even higher. To protect the pump from filter as oil passes through the holes in a
pressures higher than it is designed for, a straight path. Many of the large particles will
maximum pressure relief valve is located in or fall :0 the bottom of the reservoir or filter con-
near the pump. A further protection to the tamer, but eventually enough particles will
pump is a pick-up screen on the intake line wedge in the holes of the filter i.. , revent fur-
that prevents large pieces of contaminant ther filtration. At this point the filter must be
from getting into the pump. cleaned or replaced. The pleated paper filter
in Figure 7-57 is a surface filter.
Oil Filters
Oil contamination reduces engine life more
than any other factor. To help combat it oil
filters are built into all modern engine
lubrication systems. The two basic types of oil
filters are surface filters and depth filters
(Figure 7-56). In surface filters oil flows
straight through the filtering material,
whereas in depth filters the oil takes an
irregular path.
Ihr6:4///1,11N)

X 1184
11111111 I
(7-57) PLEATED PAPER FILTER
Courtesy 0 John Dee Ltd

42
 7:32 ENGINES

Depth Fillers in contrast to surface fillers. use

a large volume of filter material to make the FILTER
oil move in many different directions before it
finally gets into the lubrication system The
filter made of cotton waste in Figure 7-58 is an
example of a depth filter FILTERED
OIL
IL
OIL TO
BEARINGS

UNFILTERED
PRESSURE
OIL
REGULATING
VALVE
OIL
PUMP

1_01!
PAN

I BYPASS OIL FILTER

(7-59) Courtesy of John Deere Lid

A main advantage of the bypass filtration

x 7774 system is that because of the direct feed from
(7-58) the pump to the bearings there is a constant
oil pressure at the bearings, regardless of the
DEPTH FILTER COTTON WASTE TYPE condition of the filter.
Courtesy 01 .141n Deere Ltd
Full-Flow Filtration System
FILTERING SYSTEMS In the full-flow filtration system there is only
There are two basic types of filtration one oil flow that travels from the pump to the
systems* bypass and full-flOw Some larger filter and then to the bearings (Figure 7-60).
diesel engines use a combination of the two As in the bypass system. a pressure gauge
systems
and pressure regulating valve are used.
FILTER------
Bypass Filtration System BYPASS
VALVE
In the bypass filtration system there are two
separate oil flows. one to the bearings and
one to the filter (Figure 7-59) FILTERED
OIL TO
In this system. five to ten percent of the oil BEARINGS
delivered by the pump is routed or bypassed
to the filter instead of to the bearings. Alter
filtering. the oil is returned to the crankcase.
This system is sometimes called a partial :.,.)w
because only part of the supply oil is filtered
at one time. PRESSURE UNFILTERED
REGULATING OIL
The volume of oil bypassed through the filter VALVE
OIL
is initially controlled by a restriction in the PUMP

i
filter outlet However, as the :low passages
become clogged, the volume of oil through
the filter is reduced and thus so is the volume OIL
of filtered oil returning to the crankcase. Ob- PAN
viously then. the filter and the oil must be
changed regularly to provide properly filtered FULLFLOW OIL FILTER t. ;4'
oil to the system (7-60) Courtesy of John Deere Ltd

43
 ,v

ENGINES 7:33

Filter Bypass Valves (Pressure Differential Many spinon filter elements have the bypass
Valves) built into the element. When replacing a filter.
be sure to use only the recommended filter
Note the filter relief or bypass valve in the because another type may not have the built-
above diagram Every filter in a lull-flow in bypass valve.
lubrication system must have a bypass valve
When the filter is new. there is very little Bypiss valves are often used with oil coolers
pressure drop through rt. However. if the filler for the same reason that they are used with
gets clogged. the resulting additional filters. If the oil cooler becomes clogged, oil
pressure will open the relief valve and allow flows through the valve and back into the
unfiltered oil to bypass the filter and go direct- lubrication system
ly to the bearings. What would happen if a
bypass valve was not provided? When the Combination FullFlow and Bypass System
filter became completely clogged. pressure
would build up on its inlet side. This pressure A combination of full-flow and bypass
would cause the regulating valve to open lubrication systems is found in many large
completely, allowing all of the oil to return diesel engines. The full-flow filter does the
directly to the crankcase. The result: a burn- primary filtering and the bypass filter the
ed-up engine secondary filtering. As lull-flow filtered oil is
distributed to all the vital lubrication areas. a
The bypass valve. then. is a safety device to small amount flows through the bypass filter
ensure that the oil. filtered or dirty. will get to from where it drains back to the sump. An
the bearings. The valve is usually set to open exampie of a full-flow bypass system is shown
before the filter becomes completely clogged. in Figure 7-62. Note the filter bypass valve, or
Figure 7-61 shows the filter bypass valve in as Its sometimes called. the pressure dif-
two locations, inside the filter and in the filter ferential valve.
mounting pad.
Oil Outlet Spring

Volvo
Poppet
0., Oil Oat Iniet
Inlet Outlet

r-111

Sps.m

Volvo
Poppet

(7-61)

BY-PASS VALVE INSIDE BY-PASS VALVE IN

FILTER HOUSING MOUNTING FAO OF FILTER
Courtesy of John Deere Ltd

44
7:34 ENGINES

Olt MIER

EGA1N TO
CAM POCKETS

Olt ROM
MAIN
GALLERY

OIL
OftAiN
/E\
TO
OtOWER elfPASS
BITER

Gm DRAIN,
FROM OtOwER
10 PSI
DIFF PRESSURE
Ott COMER
(7-62) sy PASS VANE

TYPICAL LUBRICATING SYSTEM DRAIN TO

OP. PAN

Courtesy of Mtnostry of Education

105 PSI
SAFETY VALVE
IN Olt PUMP
SO PSI INtEr SCREEN
Olt PRESSURE
REGULATOR VALVE
18.2i
OIFF PRESSURE
Oil Coolers FILTER OYPASS
VALVE

Many lubrication systems use an oil cooler to

cool hot oil. and thus help dissipate heat -WATER
created by the engine. Most coolers use INLET
engine coolant to cool the off The oil cooler
may be mounted internally in the crankcase or
externally on the outside of the engine block.
Most engines use an externally mounted oil
cooler. like the one in Figure 7-63.
When the cooler is mounted externally both
coolant and lubricating oil are pumped
through it (Figure 7-64).
OIL OUT OIL IN
COOLANT u4k,
COOLANT WATER
VALVE 4RETURN
R #041, NOUS :NG i 11.22E
..mor
COOLANT COoLANT
OUT
wow
Itt (7.63) UiL COOLER MOUNTED
4111", OUTSIDE ENGINE
Courtesy of John Deere Ltd

(7.64) OPERATION OF ENGINE

OIL COOLER
Courtesy of John Deere Ltd

45
 ENGINES 7:35

Coolant flows through the tubes in the cooler

and oil circulates around the tubes. Heat from
the oil is transferred to the coolant which then
travels to the radiator and is itsell cooled
Another common type of cooler works op-
posite to the one above. Instead of coolant
flowing through tubes. oil is pumped through
a small radiator-like core and coolant is cir-
culated around it.
A bypass valve is used with some oil coolers
to assure 011 circulation if the cooler should
become clogged. Note the location of the oil
cooler bypass valve in the diagram of the
combined full-flow bypass lubrication system.
Trace the oil flow that would occur on a cold
start when thick oil could cause both the filter
and the cooler bypass valves to open (Figure
7-62)

Breathers and Vents (7-65)

In every internal combu.stion engine some un- Courtesy of General Motors Corporation
burned gases pass by the piston rings. If these
gases, called blow-by, are not vented they will Open ventilation is not used on gasoline
tend to build-up pressure In the oil pan. both engines today because gasoline blow-by con-
contaminating the oil and forcing the front tains harmful hydrocarbon fumes that con-
and rear pan seals to leak. Breathers and tribute greatly to air pollution. Instead.
vents remove the blow-by gases and the positive crankcase ventilation is used.
pressure.
Two basic methods are used to allow the
engine to breathe:
1. open crankcase ventilation using a road
draft tube or cover vents.
2. positive crankcase ventilation.
Open crankcase ventilation removes blow-by
gas through the road draft tube attached to
the side of the engine (Figure 7-65).

Movement of the vehicle forward at speeds of

20 mph or faster creates a low pressure at the
bottom end of the tube. Fresh air is taken in
through the fresh air breather at the top of the
engine. combines with the gases in the crank-
case. and then exits through the road tube. (7-66)
The mixture of gas and air flows out the tube Courtesy of General Motors Corporation
because the pressure of this mixture is higher
than the pressure at the road end of the tube In this system a hose passes from the crank-
(gases at higher pressure always move in the case. through a ventilation valve to the intake
direction of lower pressure). Most diesel manifold. Fresh air enters the breather cap on
engines use the open ventilation system. the valve cover. mixes with the blow-by gases.
having either a tube going from the top of the and is drawn up by manifold vacuum through
engine down the side or vents on the valve the ventilation valve and into the intake
covers. manifold. Thus the blow-by gases finally end
up in the combustion chamber again. The ven-
tilation valve. usually called a PCV valve. is a

46
7:36 ENGINES

spring loaded metering valve which regulates Motor oil must minimize the formation of
the amount of flow from the crankcase to the these contaminants in the first place. but
intake manifold when they inevitably do form. the oil must
keep the contaminants in suspension so
Besides contributing to cleaner air in the en- that they don't settle inside the engine.
vironment another advantage of the positive
ventilation system is that tf a gases are Oil must also act as a cleansing agent.
removed even when the engine is idling. The carrying to the oil filter abrasive con-
open system requires vehicle movement (20 taminants that form in the engine.
mph) to create the low pressure and the draft
necessary to remove the gases 4. Cylinder Sealant
Cylinder pressures of 145 p.s.i. at cre.:11(ing
MOTOR OILS speeds are not unusual. while combustion
Motor oils are often taken for granted. It pressures may reach 900 p.s.i. Piston rings
isn t generally appreciated that they must alone cannot seal off this pressure; they
lubricate despite high oxidizing conditions. need the help of the oil film between the
extreme temperatures. and large amounts of rings and the cylinder wall.
contaminants High-output engines coupled
with reduced crankcase capacities and ex- 5 Control Engine Octane Requirement
tended dram intervals have all compounded Motor Oil must minimize the formation of
the severe conditions under which the oil oil deposits in the combustion chamber.
must perform These deposits decrease the volume of
the chamber thereby increasing the com-
MOTOR OIL FUNCTIONS pression ratio and thus the octane
(Courtesy of Imperial Oil Limited) requirement of the gasoline. The deposits
I Wear Prevention are also a source of hot spots that can
glow and cause pre-ignition.
Wear takes place due to metal-to-metal
contact of moving parts. as well as from 6. Control Rust
acidic corrosion. from rusting and from
the abrasive action of contaminants Engine components such as valve stems.
carried in the oil. To prevent metal-to- hydraulic valve lifters. piston rings and
metal contact. motor oil musk maintain cylinder walls are subjected to severe
sufficient viscosity to provide a full fluid rusting conditions Extended periods of
film between moving parts under all engine idling or short trip stop and go
operating temperatures. The viscosity driving allow water to accumulate in the
must not be so thick. however. A to make oil Also. condensation of water on engine
starting the engine difficult parts can occur overnight when the
engine isn't running. An essential function
2 Engine Cooling of the motor oil is to provide a protective
Motor Oil is largely responsible for piston film on engine parts to prevent rusting
cooling. The cooling is done by when it's not being used.
transferring heat directly from the piston 7. Control Corrosion
through the oil film to the cylinder walls
and then out to the cooling system. and by Products of combustion in.:!ude corrosive
carrying heat from the underside of the materials. such as acids. which ac-
piston. crown and skirt to the crankcase. cumulate in the engine crankcase. Unless
Oils must therefore have good heat con- tne engine oil can control the to idency of
ductivity. but at the same time the oil must these products to corrode bearings and
have adequate thermal stability to resist other finely finished surfaces. corrosive
decomposition when in contact with these wear will reduce engine life.
hot surfaces.
MOTOR OIL COMPOSITION
3 Engine Cleaning
Motor oils are manufactured from base stocks
Over a period of time oil starts to and fortified with additives to provide the per-
deteriorate and oxidize The oxidation formance level required.
causes the formation of harmful con-
taminants acids. varnish. carbon. sludge.

47
 ENGINES 7:37

Motor Oil Additives CLASSIFYING MOTOR OILS

1. AntiOxidant prevents oil oxidation. S.A.E. Classification
sludge and acid formation.
The most important single property of a
2 Corrosion Inhibitors prevent bearing lubricating oil is viscosity. Viscosity. as stated
corrosion. earlier. is a measurement of the resistance of
3 Detergent/Dispersal cleans engine a liquid to flow. The viscosity of an oil is
parts and disperses sludge and other solid determined at specific temperatures; O'F and
contaminants. These detergents act 100'F and 210'F are the most widely used.
similarity to soaps to remove deposits and The viscosities of different oils can be com-
then to retain the deposits as finely pared only at the same temperature. The
dispersed particles in the oil. Detergents Society of Automotive Engineers (S A.E ) iden-
may become depleted and after prolonged tify oils by their viscosity ranges. Motor oils
continued service they may not be able to can have S.A.E. numbers of:
keep the contaminants in suspension. 5W
4. Rust Inhibitors prevent rusting of 10 W The higher the number the
engine parts. particularly hydraulic valve 20 W greater the viscosity (the
lifters. 30 W thicker) the oil.
40 W
o 5. Pour Point Depressant provides free-
flowing qualities at low temperatures.
50 W

Engine Service Classification

6. Viscosity Index Improver viscosity in-
dex can be defined as a measurement of As well as an S.A.E. classification. motor oils
the change in the viscosity as the tem- are also classified according to the service
perature changes. The improver additive conditions under which they will be used. In
reduces the rate at which the oil thins out 1970 a new crankcase oil performance
with increasing temperature. classification called -Engine Service
Classification" was established to replace the
7. Anti-wear Agent prevents galling and
scoring of heavily loaded engine parts. API Service Classification formerly used. it
specifically lists the tests and performance
particularly the valve train. A widely used requirements for each of the classifications,
material is a zinc-sulphur-phosphorous and in addition. is open-ended to allow for the
additive often referred to as -MOP-. addition of new performance levels as they
S. Reserve Alkalinity new engine oils are are developed.
s
basic in composition to neutralize acids The Engine Service Classification is divided
formed by the combustion processes into two categories. The -5" category refers
9. Foam Suppressor does not prevent mainly to gasoline engine low temperature
foam from forming. but renders the foam requirements while the "C" category refers
unstable so that it settles quickly. mainly to diesel engine high temperature
requirements (Figure 7.67). Many applications
Whi's there may seem to be a great many ad- will call fOr a dual rated oil such as SD/CD
ditives used in motor oils. the concentrations which requires both extremely low and high
are often very low. Anti-oxidants and temperature performance levels.
corrosion inhibitors, for example. are used at
concentrations as low as 0.1%. High additive
oils may have as much as 12% detergent
present. The quantity of additive, it should be
pointed out, is not necessarily an indication of
the quality or the strength of an oil.

48
 ENGINES

Engine Service Classification should be maintained at all times. Follow

these practices when checking oil levels and
when topping up the oil.
LETTER SERVICE DESCRIPTION
DESIGNATION 1. Park the vehicle on level ground.
SA Non-additive oils. Not recom- 2 Practise cleanliness. Use a clean rag to
mended for crankcase ser- wipe the area around the dipstick and to
vice wipe oil off the stick.
SB Ugh, Duty Gasoline Non- 3. Check the oil level before starting the
detergent Not normally engine. An engine should be stopped for
recommended for crankcase at least five minutes before the oil level
service. is checked. Some manufacturer's call for
a running as well as a stopped check.
SC 1967 and earlier gasoline The dipstick on these machines will be
engine service in passenger marked on both sides. on -Engine Stop-
cars and (rucks ped- and the other -Engine Running-.
SD 1971 and earlier gasoline Figure 7-68 gives an example of a
engine service in passenger manufacturer's directions for an oil level
cars and trucks check on a crawler dozer. Note that the
check must be done when the engine is
SE Current and earlier gasoline
engine service in passenger running.
cars and trucks EVERY 10 SERVICE HOURS
DIESEL ENGINE CRANKCASE
CA MIL12104A Light duty diesel
=
CB
engine service

Supplement 1
Moderale duly diesel engine .,
I
- ..,

service . .4
CC MIL-L-2104B Moderate duly
diesel and gasoline engine
service

CD Caterpillar Series 3 Severe

duty diesel engine service.

Refer to Block 4. Power Trains. for information

on handling and storing oil. Check oil level with engine at low idle and oil
hot Maintain oil level between FULL and
(7-67) ADD marks on ENGINE RUNNING side of
Courtesy of The Society of Automotive Engineers :5 A E ) gauge (7-68)
Courtesy of Cat erpitiar TraCtOr Co
PREVENTIVE MAINTENANCE SERVICE ON 4. Check for evidence of water or fine metal
LUBRICATION SYSTEMS particles in the oil. When such con-
As part of the daily walk around check before taminants are found. further checking
start uo to* tube system should be inspected roll be necessary to determine where
for leaks. damage or deterioration. When they are coming from.
minor leaks are spotted. tighten fittings or 5. Keep records of quantities of oil added
bolts: if this doesn't stop the leak report the between changes: a sharp increase of
condition to a supervisor Oil leaks should be top-up oil usually indicates a rapidly
attended to immediately. To be able to see developing problem.
leaks better. keep a machine clean by regular
steam cleaning or high pressure washing. 6. Contaminated oil can seriously reduce
engine life. When top-up oil is required
Oil level checks are a vital part of routine be certain that the oil container has no
maintenance on a vehicle Correct oil levels water or dirt in it. Human error in not
 ENGINES 7:39

keeping oil dean is one of the most com- It musi be stressed that a good oil sample.
mon way . that contaminants enter an one that is not cross-contaminated with
engine another oil system. is essential for an ac-
curate laboratory analysis
7 Use only oil recommended in the service
manual
8 Do not mix engine oils
9 Do not overfill the crankcase
10 Never operate an engine if the oil quan-
tity is below the low-ievel mark

CHANGING ENGINE OIL

Over a period of time oil gets dirty and wears
out making it unfit for use. On the other hand.
lust because crankcase oil is black. doesn't
necessarily mean the oil has to be changed
Since it s difficult to tell by just looking at oil
when it should be changed. the best policy is
to follow the manufacturer's recom-
mendations on oil and filter changes.
In addition to scheduled oil changes many
companies are now carrying out oil analysis
programs The term oil analysis reiers to a
laboratory analysis of used oil which deter-
mines the types and amounts of wear metals
present in the oil By charting on a regular
oasis the amount of certain metals in oil. the
condition of the parts that the oil lubricates
can be watched When a concentration higher
than has been the pattern of a certain metal
begins to appear. it indicates that the part
from which the metal has worn off is starting
to wear more rapidly. The laboratory can warn
the customer to take protective action prior to
the unit failing Laboratories have con-
siderable experience in detecting wear pat-
terns from used oil and can fairly accurately
state the condition If internal components
providing that sampling is done on a regular
basis
In an oil analysis program. oil samples must
be taken from each lubrication system on the
machine. e g engine oil. hydraulic oil. final
drive oil. brake and transmission fiuid For oil
analysis to be successful Amples must be
taken on a regular basis: between 125 and 250
hours for engine oil and 250 to 500 hours for
all other lubrication systems Oil samples
must be taken when the oil is warm and
thoroughly mixed There are various methods
of taking the samples a valve or petcock put
straight into a main oil line. a suction gun with
a sample jar to take ail from dipstick and oil-
fill holes. a thick rubber bulb including a one-
way check valve a vac cap and a sample jar.
50
 7:40 ENGINES

SPE 3 VEAR/CONtM4INAT1ON (SAMPLE)

\NIP , deldtrie0/1
BOX 41608
UNII. 1330
;On DETROIT DIESEL,
XYZ TRUCKING CO. INDIANAPOLIS IND 46241 MODEL 8V -71
TYPE
ACC; NO S
Mfr GNI* URSA
UNIT CONDITION AND RICVAUNDATIONS

Piston pin bushing metal; Resample at NORMAL interval.

2L piston metals; Ring /cylinder metals; Check blow-by (compression); Resample at NORMAL interval.

3r- Piston metals, Ring/cylinder metals; Inspect cylinder areas; Resample at NORMAL Interval.

r_ Piston sets's. Ring/cylinder metals, Inspect cylinder areas, Resample at NORMAL interval. FEEDBACK. Several broken rings
4
and scored liners. Vtist pins
---7--
J-
- TESTS INDICATE UNIT IS IN SATISFACTORY CONDITION. Rasample at NORMAL interval.

mgiALSPARTSPERMst.tsONBrwEsGitt
DATII coNtamimArION USE DATA
I .
E
S Soso* S...
t .3 Fuel latO
7
N
140.A COsIn
K
0
a a... -.
u 0
, 3 3
: Z %%NO
W4I4
1ANS
ANS
210°F Bier
WS No
0 0 Sw.4.1, 5.4, E
z
-
O.' 0
,
> 8
,7)

5
An 0 0 $4**, P m 4 x
.a.., u 0. m
:I
u n
-4

vo= ;Z Mita.) RI 032. 003. < 008. 002. 000. 000. 006. 023. 001. OIO. 2300 0000M ,1111111;10"1:6
2
AIRRaE71) 003. 002. 009. 002. 000. 000. 007. 030. 001. 010. !4_. 30002 NM 30t05
riig224 t 0, 003. 002. I
009.,003. 000 000. 006. 001. 010. 2400 0000ERIE 1.0 EVE
ita 11:
IM:01"..T1 P-4(401,
m-z...71.12.1110003 002. 006. 006. 0001. 000. 000. 007 002. 010. 2620 ,I!!!!!!!
1,, rizgliP!
,, a.
191;;Figg;;;;0 030. 001. 001. 006. 003. 001. 000. 000. 006. 030 010. 2390 taNTIIIII C411:1119!!

RE
1

6
.11 Ill 1.
Gv okot OWL (04( ell t XP(101 Ne(a 1,01.4,f ovaied too.renples.

NOTE Or. 41.1. to 9. ',A, 401/1, 404 Dyed on to e. ..not.on wat tr.e Lamp. snd det4 town A
$ A...,1,$) 4. 4*. Al-' 14110Ia 4 *4000. 4 M.LTbtlo, ..,669( AA. ()N.,. Mb ft qv( 09*6

(7-69)
Courtesy of Lubrecon Consultants Inc

51
 ENGINES 7:41

PROCEDURES FOR CHANGING OIL AND 7. Wash the filter housing(s) and install a
OIL FILTERS new filter element. Replacing some oil
filters requires installing new gaskets or
Procedures for changing oil and filters are sealing rings. Be sure the sealing sur-
much the came for all engines However. the faces on the engine and filter are clean.
number f.,f filters, the drain location and the
capac.(y of the system will vary from engine to 8. Replace all drain plugs.
engine Some good practices to follow are
9 Referring to the Service manual for the
1 Move the vehicle to a level area. correct type and amount of oil. fill the
crankcase with oil.
2. Run the engine long enough (15 minutes)
to warm the oil. and then stop the engine. 10. Remove crankcase breathers and
When the oil is warm contaminants will thoroughly wash them with solvent or
mix with the oil and will dram out with it. kerosene. Below are typical directions
frail a service manual on how to clean a
3 Make sure you know the capacity of the breather:
system and have a container large
enough to hold all the drained oil. Clean breather element (Figure 7-71)
in cleaning solvent and dry with com-
4 If an oil sample is to be taken. do so at pressed air. Wipe out breather
this point (Within 15 minutes of shut- housing. Soak element in oil: drain out
down ) excess. Check gasket: replace if
5 Remove the plug carefully. Caution: Hot damaged.
oil can burn.
6. Drain the filler(s) if they are equipped
with a drain. and then remove the filter
element. Take a few seconds to inspect
the old filter element (Figure 7-70).
especially if oil sampling is not done.
Evidence of metal ships will indicate that
there are problems within the engine
requiring immediate attention.
_ 46

St,
494-
' .11
err "- r-
.1.
\
.414 44444144 ..-4.4414 -"OW"

(7-71) CRANKCASE BREATHER MESH ELEMENT

Courtesy of Cummins Engine Co

11. Start the engine. run for ten minutes and

check for leaks.
12. Check oil level with engine slopped and
top-up as required.
AV& 13. Keep a record of all oil and filter changes
to be sure of regular engine service
(7-70) INSPECTING PAPER ELEMENT PLEATS
14. New or rebuilt engines require oil and
COurtoSy of Cummins Engine Co filter changes after a specified break-in
4 period. Performing this service on time is
very important since foreign materials
accumulate in the oil at a faster rate
during initial operation than later when
the engine is broken in.

52
 7:42 ENGINES

Flushing The Lubrication System

A lubrication system is generally flushed
when it becomes contaminated with coolant.
fuel. or metal chips What flushing amounts to
is changing the oil twice To flush the engine
follow the same procedure as changing the
oil drain. change filters. refill Refill with the
same grade of engine oil as regularly used or
with a recommended flushing oil Run the
engine until the oil is warm. and then com-
pletely drain the system and discard the
filters
Renew ;he filters. including new seal rings
Refill the crankcase Run the engine and
cht.,..K for leaks Shutdown the engine and
Nat
check the oil level
For an engine that is contaminated with metal
chips such as would occur after an internal
failure. the same flushing procedures would
apply as above. but with these additional
flushing and precautionary measures.
I Remove the oil cooler and flush it.
2 Remove any external lines such as a
bypass filter line. flush and blow them
clean with compressed air
3 II the engine has a turbo charger. remove.
flush and blow clear the turbo tube lines

53
 ENGINES 7:43

QUESTIONS LUBRICATION SYSTEM 14 What are the two categories that engine
oils are divided into for service
1 Two of the functions of the lube system classification?
in an engine are to reduce ___
between moving
parts and absorb and dissipate _ 15

16.
What is 081 classified as CC suitable for?
True or False? An engine should be stop-
ped for at least five minutes before the
2 True or False? Most engines today use a oil level is checked.
full-pressure lube system.
17 What does the term oil analysis refer to?
3 What protects the oil pumps from over
pressurizing? 18 What is considered to be an ideal sampl-
ing interval for engine oil analysis?
4 What are the two common types of 081
filter systems (a) 10 to 50 hours
(b) 50 to 100 hours
(a) Full pressure and low pressure
(c) 125 to 250 hours
(b) Full flow and bypass
(d) 250 to 500 hours
(c) Full flow and medium flow
(d) Partial flow and bypass 19. What information can a regular oil
analysis program give you?
5 Give an example of a surface filter-
element. 20. Why should oil be warm when it is
drained for changing?
6 On a bypass filter system when the oil
has passed through the filter it goes to 21 Under what three conditions would it be
the- necessary to flush the engine's lube
system?
(a) bearings
(b) valve cover
(c) camshaft
,d) crankcase
7 On a full-flow filtration system the oil al-
ter passing through the filter goes to the.
(a) bearings
(b) valve cover
(c) camshaft
(d) crankcase

8 What occurs within a lull-flow oil filter if

the filter becomes plugged?
9 What is the function of the pressure dif-
ferential valve between an inlet and
outlet line of an oil cooler?
10 Why is crankcase ventilation so im-
portant?
12 True or False? There is a simple
equation between additives and oil
quality the more additives, the better the
oil
13 The S A E number identifies oils by their
range The higher the
number the ________ the oil

54
7:44 ENGINES

AIR INDUCTION SYSTEM The naturally aspirated system. often referred

to as N.A . IS the simplest of the air induction
The air Ind. ctton system must* systems. The term naturally aspirated is ex-
1 Supply an abundance of clean air for com. p:ained as follows* asphalting refers to the
bustion The air must be at the right drawing in of air. A naturally aspirated engine
degree of coolness and the air intake I.; said to draw in air or breathe naturally On
n.ust not be too noisy the piston's intake stroke. air via the air
cleaner is drawn into the engine. No aids are
2 Supply a.r to aid in scavenging burned used to help get the air in or out of the engine.
gases from the cylinder. air is drawn in because atmospheric pressure
IS higher than the pressure in the cylinders.
Three types of systems are used to supply air
to an engine: In a naturally aspirated 08 N.A. engine (Figure
Naturally aspirated.
7-72) air enters the cleaner and flows to the
1 and naturally
carburetor where it mixes with gasoline. From
aspirated and scavenge blown
the carburetor the mixture travels through the
2 Turbo charged. intake manifold and enters the combustion
chamber at the intake valve.
3 Turb: charged and after cooled.
In a naturally aspirated engine. since there is
no carburetor. air travels directly from the
cleaner through the intake manifold and into
the combustion chamber where it is mixed
with injected fuel.

7
PRE-CLEANER
MUFFLER

CARBURETOR ON GASOLINE
Th ENGINE

EXHAUST
VALVE
VALVE

AIR CLEANEK

EXHAUST
INTAKE MANIFOLD
MANIFOLD

(7-72)
CYLINDER
NATURALLY ASPIRATED AIR SYSTEM

Courtesy of John Deere Lid

55
 ENGINES 7:45

A naturally aspirated. scavenge blown air One of the drawbacks of a naturally aspirated
system is similar tv the basic N.A. system ex- air system is that the amount of air that the
cept that an air pump. driven by the engine is engine can take in is limited and therefore the
used to supplement the natural intake stroke engine's horsepower is limited A turbo
breathing. This scavenged blown system is charged system brings more air into the
used on two stroke cycle diesel engines (e g.. engine cylinder and thereby increases the
Detroit Diesels) when intake ports rather than engine's horsepower The turbo charged
intake valves are used (Figure 7-73). system uses an exhaust driven turbine to drive
an air compressor. By compressing the air
The air pump. called a Roots Blower. creates more of it can be packed into the combustion
a positive pressure approximately 4 psi within chamber. With more air (i.e., oxygen) in the
a chamber that completely surrounds all the cylinder. more fuel can be burned 9n the
cylinders The chamber is called the air box power stroke and thus the increase in horse-
When the piston is at its lowest point the in- power. Although a turbo charger is a
take ports are open and the exhaust valves precision built device that can operate at
are also open Fresh pressurized air in the air speeds up to 130,00 RPM, it is a relatively sim-
box rushes into the cylinder forcing the ple. durable piece of machinery Figure 7-74
a exhaust gases out through the open exhaust shows the basic parts of a turbo charger.
valves. The pump ensures complete
scavenging of all the exhaust gases (thus the
name scavenge blown), as well as ensuring a
plentiful supply of fresh air for the next power
stroke
AIRBOX

EXHAUST
VALVE

4
PUMP

INTAKE
PORT

INTAKE AND EXHAUST COrArRESSION POWER

(7-73) ONE-VALVE TWO-CYCLE ENGINE

WITH BLOWER
Courtesy of John Deere LW

THRUST COLLAR

FLOATING
BEARINGS

SHAFT

COMPRESSOR

'3432 TURBINE
Courtesy 0 John Deere Lid
(7-74)

56
 7:46 ENGINES

Exhaust gases on their way to the muffler pass

through the turbine housing and rotate the
turbine wheel The turbine wheel in turn drives COMPRESSOR
the compressor The compressor takes air AIR DISCHARGE
that has come in from the air cleaner. com-
Presses it. and discharges it into the intake TURBINE
manifold where it travels to the combustion WHEEL
chamber (Figures 7-75 and 7-76).
TURBINE
EXHAUST AMBIENT EXHAUST GAS
TURBOCHARGER
AIR loft, OUTLET
tiNILET

4:1:Zi EXHAUST
AMBIENT AIR GASES
COMPRESSOR
WHEEL
EXHAUST GAS
INLET
(7-75) (7-76) TURBO CHARGER
ENGINE CYLINDER Courtesy of Detroit Diesel General Motors Corpora..on

INTERCOO LERS
OPERATION OF BASIC TURBO CHARGER
Courtesy of Jurrn Deere Lid
When the turbo charger compresses the
engine intake air. the air becomes heated
(due to compression) and expands. When the
The increase in the pressure of the com- heated air expands, it becomes less dense.
Pressed air delivered by the turbo charger IS
called boost pressure The beauty of a turbo The result is that part of the purpose of the
charger is that boost pressure is at its highe6i turbo charger is defeated because less air is
forced into the engine. To overcome this con-
when the engine needs tt most. Since the
dition. some turbocharged engines are equip-
compressor IS run by exhaust gases. boost
pressure IS at maximum when the engine is
ped with an Intercooler. An intercooler is
operating at full load Tne boost can reach 15
-*thing more than a heat exchanger; the
heated intake air flows over a series of tubes
p s i or higher The increase in boost pressure
through Ix hick engine coolant 8s circulated
as the engine load increases is important In
ane tne air is coaled, as shown in Figure 7-77.
terms of getting the air onto the cylinder
When an engine is running at 2500 RPM the
intake valves are open less than .017 seconds.
With the air under greater pressure. it takes
less time for it to get Into the cylinder In ad-
dition to turbo chargers. some engines are
equipped with a cooler Installed between the
turbo charger and the intake manifold. It IS
referred to as an after-cooler or intercooler
Such an arrangement is called turbo charged
and alter cooled
A
5
-.-

6 7 I" 8
(7-77) t14IU
AIR INDUCTION AND EXHAUST 1Coolant inlets to altercoolers 2Coolant
(SCHEMATIC) outlets from aftercoolers 3 Aftercoolers
Cotine of CafernMar itaCiOf Company 4 -Aircleaner air inlet 5Air transfer pipes
6Turbo charger compressor impeller
7Turbo charger turbine wheel
8Exhaust outlet 0-- Exhaust mandold

57
 ENGINES 7:47

The intercooler reduces the temperature of

the compressed atr by 25 to 30'C. The
reduced temperature makes the air denser
allowing more to be packed into the com-
bustion chambers The result is.
1. More power: Sufficient air is provided to
burn the fuel resulting in higher horse-
power.
2. Greater economy The fuel is burned more
completely. giving more power from a
given amount of fuel.
3. Quieter combustion' By lowering the tem-
perature of the air for fuel-air mixing.
there is a smoother pressure rise in the
engine cylinder. Figure 7-78 shows a
typical intercooler mounting
(7.78) TYPICAL INTERCOOLER MOUNTING

HOUSING LINKAGE INLET TUBE

SHUTDOWN SHUTDOWN
-
/ 111111
HOSE
'(":
t1

CLAMP

SHUTDOWN
4,,SOLENOID
:4:;17:4.

rY
INLET INLET
HOUSING HOSE
ADAPTOR

OIL
SUPPLY
LINE

OUTLET
+. HOSE
Azp
ohm.
INTERCOOLER
WATER
MANIPOLD?ki,''t"- TURBOCHARGER
)-;.,"4>.
t..F.F
SOB

Courtesy of Geffen! Motors CorPontion

58
7:48 ENGINES

AIR CLEANERS matter from the air before it enters the main
air cleaner. They relieve much of the load on
Clean air is essential to satisfactory engine the air cleaner and allow longer intervals be-
performance and long engine life. The air tween servicing. Most pre-cleaners have a
cleaner must remove fine materials such as pre-screener which prevents lint. chaff. and
dust and blown sand as well as coarser leaves from entering the air intake.
materials such as chaff or lint. This residue
collects in a reservoir which must be large
enough that operation is maintained over a
reasonable period of time before cleaning and
servicing is necessary. If an air cleaner is not
cleaned buildup of dust and dirt in its
passages will eventually choke off the air sup- COLLECTOR
ply. causing incomplete combustion and BOWL
heavy carbon deposits on valves and pistons (7-79)
Multiple air cleaner installations are PRE-CLEANER
sometimes used where engines are operated
under extremely dusty air conditions or where
two small air cleaners must be used in place
of a single large one. R 40$ PRE-SCREENER
The most common types of air cleaners are Pre-Cleaners and Re-Soreeners Keep Large
Foreign Particles From Reaching the Air Cleaner
1. Pre-cleaners
Courtesy of John Deere Ltd

2. Dry element cleaners Dry Element Air Cleaners

3 Oil bath cleaners Cylindrical Dry Element Cleaner (vane and
tube type)
PreCleaners
Atmospheric air enters the inlet opening of a
Pre-cleaners (Figure 7-79) are usually in- dry element air cleaner (Figure 7-80) where it
stalled at the end of a pipe extended upward immediately travels through a ring of vanes or
into the air from the air cleaner inlet. In this tubes which create a cyclonic twist to the air.
location pre-cleaners are relatively free of The air twist throws most of the dust and dirt
dust Pre-cleaners are simple devices which particles outward and down into a removable
remove large particles of dirt or other foreign dust cup. The air, now cleaner. passes
through a paper filter which removes the
remaining dust.

(7-80)
Dry Element Type
Air Cleaner

CouriesY 01 John Deere Lid

 ENGINES 7:49

Panel Cartridge Dry Element Cleaner

MOISTURE
Pane cartridge dry element cleaners (Figure ELIMINATOR
7-81) have a twostage cleaning process
similar to the cylindrical models Deflector
vanes create a twist in the incoming air which
throws out most of the dust. The air then
spirals back through the cleaner's element (7-83)
which removes the remaining dust.

FIRST
STAGE Courtesy of
Cummins Engine Co v--- DUST BIN

Oil Oath Cleaners

Oil bath cleaners have a cleaning element in-
side a housing that contains oil (Figure 7-84).
Incoming air reverses when it strikes the sur-
face of the oil causing most of the dirt to be-
SECOND STAGE come trapped by the oil and settle in the
sump. Tho air then passes upward through the
(7-81) main cleaner element where more dust and
PANEL CARTRIDGE AIR CLEANER suspended oil is removed. These second-
Courtesy of Cummins Engine Co stage filtered contaminants drain back into
the sump and also settle out of the oil. Clean
Some panel cartridge air cleaners use an
exhaust aspirator to remove the dust through
air leaves the cleaner at the air outlet. Light.
the exhaust system (Figure 7-82)
medium and heavy duty cleaners are
available. Note that the space above the main
element in the air cleaner acts as a silencer to
subdue intake noise. Courtesy of John Deere LW

AIR
INLET

MR
OUTLET
(7-82)
CARTRIDGE TYPE-AIR CLEANER-TWO STAGE AIR
Courtesy of Cummins Engine Co TUB 71

Other panel cartridge air cleaners replace the

first stage of cleaning with a moisture MAIN
ELEMENT
eliminator Some vehicles such as on-highway
trucks are subjected to water/salt spray and %
I ER
the incoming air needs to have the moisture OIL CUP
removed from 0 before it reaches the dry filter
element Attached to the front of the cleaner.
the eliminator traps and expells the moisture
from the wet air and then sends the dry air to OIL
be further cleaned by the paper fillers (Figure CUP
1-83)
(7-84)
AIR FLOW THROUGH HEAVY-DUTY OIL
BATH AIR CLEANER
60
7:50 ENGINES

CLEAN
AIR TO
ENGINE
FILTERING
ELEMENT

OIL SPRAY
DRAWN UP,
CLEANS
PARTICLES
FROM AIR
;41, Service filter element when red signal reaches
SERVICE LEVEL, then reset indicator.
OIL CIO 4,4:
(7-85) AIR FILTER RESTRICTION INDICATOR
Courtesy 0 General Motors Corporation
1,"

(7-84) MEDIUM-DUTY OIL BATH AIR CLEANER

couslesy ol John Deeoe LIct

AIR FILTER RESTRICTION INDICATOR

The air filter restriction indicator (Figure 7.85)
is a warning device that tells when the air ,r;:f44:**
I
filter is dirty and needs to be serviced. The in-
dicator is constructed s the warning notice is
given before any damage occurs to the
engine as me rssult of a clogged filter
elemen: The res:riction indicato: is located in
the air inlet manifold and is readily visible 4
when the engine compartment is oper, The in-
dicator itself requires no service other than I
resetting.

When the fillet element is clogged to such a

degree that air flow is restricted, a red in-
dicator ring appears in the transparent area of 1-6413
the body marked "service level". This is the
signal that the air cleaner must be serviced.
After servicing the cleaner, the indicator is 111111MIM111.
reset by depressing the buttor on top of it.
The red ring will then move out of the trans- (7-86) AIR FILTER RESTRICTION GAUGE
parent area of the indicator. (TYPICAL)
NOTE Some vehicles will have an air Cowiesy OI General Motors Corporal or
restriction gauge rather than an in-
dicator The restriction gauge (Figure
7-86) is located on tne panel board in
the cab and performs the same func-
tion as the indicator.

Si
 ENGINES 7:51

TUBING, HOSE AND CLAMPS FOR

MR INDUCTION SYSTEMS
Air induction piping works in conjunction with
the air cleaner to carry clean air to the engine. 4

Itis importelt that all the piping joints are

properly sealed and free of leaks. An air
cleaner is completely ineffective if leaks oc-
cur in the piping between the air cleaner and
the engine.
Dirt is the basic cause of wear on pistons. (7-88) CONNECTING HOSE
rings. liners and valves. One of the most prob- Counesy of Cummins Engine Co
able places for dirt to enter an engine is
through an opening in air induction piping. Molded Rubber Elbows
Field experience has shown that most air
leaks occur when wire reinforced hoses are To make angular connections molded rubber
used in the au induction system. The leaks elbows are used (Figure 7-89) Elbows are
are caused by wire wearing through the hose available in both 90° and 45° angles A 90°
fabric and they are often barely visiLle to the elbow with ribbed reinforcement is also
naked eye. Even a very small hole can allow available to prevent possible collapsing under
large quantities of duty air to enter an engine. high temperature conditions or high inlet
Therefore. wire reinforced hose is not recom- restriction.
mended for air induction tubing.

Smooth-Welded Steel Tubing

Smooth-welded steel tubing (Figure 7-87)
should be used instead of flexible hose or
metal tubing that has rough-weld steel tubing
angle joints Smooth welded steel tubing has
a smooth surface that gives a good sealing
contact with rubber connecting hose.

(7-89) MOLDED RUBBER ELBOWS

Courtesy of Cummins Engine Co

Hose Clamps
"T" bolt type non crimping hose clamps
(Figure 7-90) should be used on air induction
systems When tightened. the clamp exerts
equal pressure around the circumference of
the hose. A lock nut prevents the clamp from
s..pping. and thus assures a tight permanent
seas
(7-97) SMOOTH-WELDED STEEL TUBING
Counesy 0 Cummins Engine Co

Connecting Hose
Steel tubing is joined by connecting hose
(Figure 7-88). The hose has a built-up hump at
liS center to give It strength and durability.
Note that ideally two pieces of tubing when
connected by a hose should be 3/4 inch (19
mm) apart.
(7-90) TBOLT HOSE CLAMP
Courtesy of Cummins Engine CO

82
7:52 ENGINES

Figure 7-91 illustrates the tubing, connecting

hose and clamps used on a typical dual inlet
air induction system for a large engine

A 3975

1 Inlet Cap 8 Clamp

2 Extension 9 Tube
3 Clamp Assembly tO. Air Cleaner Assembly
4 Either Starting Aid 11 Band Brackets
5 Tube 12 Front Supports
6 Support 13 Rear Supports
7 Elbow 14 Engine Inlets

Courtesy of General Motors Corporation

(7-91)
 ENGINES 7:53

PREVENTIVE MAINTENANCE ON AIR

INDUCTION SYSTEMS
Good maintenance practices on air induction
systems'
1. Keep the air cleaner-to-enine con-
nections tight.
2. Keep the air cleaner properli assembled
so all joints are oil and air tight.
3. Periodically make a careful examination
of the air induction system for leaks. Over
a period of time enough dusty air can pass
through even a small crack to severely
damage the engine
4 When conditions are dusty frequently in-
spect the cleaner.
5 Service oil bath cleaners often enough to
prevent oil from becoming thick with
sludge
6 Use the correct grade of oil. Keep the oil
at the proper level in the cup. Do not over-
fill
NOTE Oil from an overfilled cup can be
drawn into an engine. The over-
flow oil can cause a diesel
engine to run away (overspeed)
and severely damage itself.
7 Always practice cleanliness when
working on air systems. Some points of
caution are:
(a) Be careful when working around an
open air intake with the engine run-
ning. Rags. loose clothing or other
objects can be drawn into the engine
and severely damage it.
(b) Never leave an intake pipe open. Ar-
ticles can be dropped into an open
pope and cause serious damage
when the engine is started. Don't
cover the opening with a rag but with
something hard such as a piece of
plywood.

64
7:54 ENGINES

AIR CLEANER SERVICE

Refer to the service manual about cleaning
procedures for particular air cleaners. Typical "ft
air cleaner service procedures are given
be low.
FILTER
ELEMENT
Pre-Cleaner and Pre-Screenar Service
RESTRICTION
COLLECTOR I.NDICATOR
BOWL NN BAFFLE
AIMIA
,Af

O 0 0
O 0 DUST CUP
0 0
PRE-SCREENER 0 0 X 1974
O
0 0
0 0 (7-93) DRY ELEMENT TYPE AIR CLEANER
Courtesy 0 John Deere Ltd
0
Clean the filter element at the following times:
1 Units with restriction indicators: clean the
element whenever the indicator signal
shows a restriction.
2. Units without indicators: clean the
(7-92) element at recommended intervals or
more often during dusty or unusual
Courtesy 01 John Deere LW operation

If too much dirt is allowed to collect in the pre- To clean the filter element shake it vigorously
cleaner. it becomes clogged and a greater to remove most of the dust Use compressed
load is placed on the main cleaner. Remove air or a vacuum cleaner to remove any
the pre-screener and blow or brush off any ac- remaining dirt (Figure 7-94).
cumulation of lint. chaff. or other foreign mat-
ter (Figure 7-92) If the pre-cleaner has a
removable collector bowl. take it off and
thoroughly clean it.

Dry Element Air Cleaner Service

Servicing dry element air cleaners involves
emptying the dust cup and either cleaning or
replacing the dry element (Figure 7-93) The
element should be replaced if It Is damaged or
if it has been in normal service for one year.

R1:00 R

Patting The Element Slowing' ;.lenient

(7-94) CLEANING THE DRY ELEMENT

Courtesy of John Deere Lti

65
 ENGINES 7:55

II the element is still dirty. it can be washed in

a solution of luke warm water and commercial
filter-element cleaner or similar non-sudsing
detergent Washing dry elements has become
quite common because of the high cost of the
elements They can be washed up to six times
The washing can be done in a shop but more
likely the elements will be sent out to com-
panies who provide this service. Spare
elements should be kept on hand to use in
vehicles while others are being washed and
dried. After an element is washed it should be
checked and stored as shown in Figure 7-95)
CHECKING ELEMENT

(7-96)
HEAVY-DUTY AIR CLEANER OIL CUP AND TRAY
Courtesy of John Deere Lid

To clean the element soak it in solvent to

loosen accumulated dirt. Thoroughly flush the
insert light inside clean and element by rcnning solvent through it from the
dry element Check element. air inlet end. Allow excess solvent to drip out
Discard element if pin holes or Blow out the element with compressed air
tears are found
CAUTION: Never attempt to clean the
element with a steam cleaner.
The force of the steam cannot be
maintained throughout the
element and will only force the
dirt to the center of the element.
Wipe out the center tube with a clean lint-free
cloth. Inspect the inside of the air cleaner-to-
manifold pipe for accumulation of oil and dirt.
If necessary. remove the pipe and clean it. A
heavy duty oil bath cleaner is cleaned in a
2 Wrap and store elements in a similar way to a medium duty one. In addition.
a clertn dry place though. some heavy duty cleaners have a
collector screen(s) attached to the inlet tube
(7-95)
Coqu'ecy of Caterotat fraclor which must be cleaned. Wash the screen in
solvent and blow it out with compressed air.
When a clean sere en is held up to the light. an
Medium and Heavy Duty Oil Beth Air Cleaner even pattern of ligot should be visible If the
Service screen doesn't pass this test repeat the
cleaning operation or replace it.
For a meaium-duty air cleaner. remove the oil
cup. pour out the oil. remove the sediment and NOTE. The fixed elements of heavy-duly air
tnoroughly clean the cup (Figure 7-96). When cleaners are self-cleaning However.
refilling the cup use the same oil as is used in it may be necessary to remove and
the engine Inspect the under-surface of the clean these elements periodically
fixed element for a collection of lint. trash. or See the operator's manual for com-
other foreign matter If any of these are plete in formation.
present. the cleaner should be removed and
cleaned.

66
7:56 ENGINES

QUESTIONS AIR INDUCTION SYSTEMS 12 When Servicing an oil bath air cleaner.
1 What are the three types of air ino...ction
what is the danger of over filling the
cup'?
systems used to supply air to the engine?
2 Briefly explain how a scavenge blown 13 List two safety practices to be observed
engine differs from a natural aspirated when working on an air induction
system
engine.
3. The Turbo charger is driven by 14 How often should a dry air later element
be cleaned/
(a) gears in the engine 15 Why should an oil bath air cleaner not be
(b) oil pressure steam cleaned?
(c) exhaust driven turbine
16 True or False/ A minor leak in air in-
(d) intake driven compressor duction piping between the air cleaner
and the engine probabli won't do too
4 How does a turbo charger get more air much damage.
into the combustion chambers than a
naturally aspirated engine'? 17 What type of oil is used in an oil bath air
cleaner.
5 Under what condition does a turbo
charged engine receive its maximum 16 In a medium-duty oil bath cleaner the
boost pressure/ cleaner should be removed and cleaned
6 An after cooler (intercooler) is used o.1 a
if
turbo charged engine to: (a) the oil is low
cool the exhaust gases (b) the oil appears to be dirty
cool the inlet air before it enters the (c) lint and other contaminants appear
engine on the underside of the element
cool the inlet air before it enters the
turbo charger
cool the exhaust manifold
7 What are the three most common types
of air cleaners'

8 True or False If an engine has a pre-

cleaner it doesn't need a main air
cleaner

9 What is the purpose of the circular or

deflector vanes in the dry element air
cleaner?
10 In an oil bath air cleaner. what happens
to the air when it strikes the surface of
the oil/
What indication does an air restrictor in-
dicator give when the air filter needs ser-
vicing/
(a) a light comes on
(b) a buzzer sounds
(c) a red band is visible on the indicator
(d) It won't allow the engine to start

67
 ENGINES 7:57

EXHAUST SYSTEMS
The function of the exhaust system is to
collect exhaust gases from the engine cylin-
ders and disperse them. quietly The exhaust
system consists of the following parts* REVERSE-FLOW MUFFLER
Exhaust Valves seal the burning gases within (7-98)
the cylinder until most of the energy has been Courtesy of John Deere Ltd

expended. and then open so that the cylinder

can clear before the next air or fuelair charge MUFFLERS
is admitted There are two common types of mufflers:
Exhaust Manifolds receive burned gases from Straight-through
each cylinder and carry them away from the
engine (Figure 7-97) Some heat from the Reverse-flow
exnaust manifold is used in gasoline engines Straight-through mufflers consist of a per-
to maintain the intake manifold at the proper forated inner pipe enclosed by an outer pipe
temperature roughly three times larger in diameter. The
space between the pipes is sometimes filled
with a sound-absorbing and heat-resistant
material (Figure 7.98).
Reverse-flow mufflers are hollow chambers
using short pieces of pipe and baffles to force
the exhaust gases to travel a back-and-forth
path before being discharged (Figure 7-98)

Mufflers reduce engine noise. but at the same

time they must not restrict the flow of exhaust
fi$ gases enough to cause back pressure in the
exhaust system. Back pressure causes in-
complete cylinder scavenging which in turn
(7-97) causes loss of power and increased fuel con-
EXHAUST MANIFOLD IGASOLINE ENGINE! sumption Excessive back pressure can even
counesv of John Deere Ltd damage combustion chamber components.
For each two ps i. of back pressure about four
Turbo Chargers use exhaust gases to drive engine horsepower are lost. The trade-off in
the compresso- turbine muffler design then is to keep back-pressure
Mufflers carry away exhaust gases and heat. at a minimum while keeping the noise at an
and muffle engine noise The exhaust ports in acceptable rwel. Note that special mufflers
the engine and the passages in the exhaust are made to minimize the additional noise on
manifold are large enough to allow complete systems that have engine brakes.
scavenging and expansion of the escaping
gases If any burned gases were left in the
cylinders following the exhaust stroke. the
amount of air or fuel-air mixture that could be
taken in on the next intake stroke would be
limited Engine power would be reduced and
fuel consumption it used

/1 II I -TM
STRAIGHT-THROUGH MUFFLER

(7-98)
Courtesy of John Deere Ltd

68
 7:58 ENGINES

Muffler and piping size is related to engine Leaks can be detected by running your hand a
capacity Usually the muffler volume is equal few inches abwe the pipe while the engine is
to six to eight times engine displacement running. Damaged or corroded exhaust
(engine displacement is the total volume of system components should be replaced
air /fuel mixture an engine theoretically can valho...t delay for both engine efficiency and
take into all cylinders in one cycle) Bends in ve safety.
exhaust piping should be gradual. not sharp.
so that gas flow is not restricted. The general
rule for bends is that the radius of the bend be SOME POINTS ON EXHAUST SYSTEM
fou: to I've times the diameter of the tubing REMOVAL AND INSTALLATION
For example 3 inch tubing should have a 12
inch radius bend (Figure 7-99) 1 Caution: One of the products of com-
bustion is carbon monoxide This is a
deadly. odorless. poisonous gas. Provide
good ventilation anytime the engine is
operating
2. Be careful of hot pipes and muffler(s) if
the engine has been running recently.
When removing pipes and the muffler.
support the whole assembly to prevent it
from falling on you when the clamps and
bolts are removed.
3. Exhaust components must have a 3/4 inch
clearance with the frame or the cab. Com-
(7-99) RAMPS OF BEND ponents without proper clearance v..
frequently the cause of annoying noises
Bends in exhai..-1 pipe are not usually made in and rattles. The 3/4 inch clearance is also
shops: custom lengths and bends are necessary to prevent overheating of the
available from manufacturem cab paneling. If needed, a metal or
Vehicles working in forested and industrial asbestos heat shield can be installed on
areas where fire may be a hazard have a fur- the part of the pipe that passes a critical
ther addition to their exhaust system a
area To get proper clearance. leave all
spark arrester A spark arrester is a screen clamp assemblies and muffler strap bolts
over the exhaust ot oet to reduce the chances loose temporarily until the entire system
of hot pieces of carbon or sparks being has been inspected to determine if there
discharged. is adeqv Ite clearance between exhaust
components and frame members. While
"tr the clamp and bolts are loose also check
PREVENTIVE 1TENANCE ON to see that the weight of the exnaust
EXHAUST SYSTEMS system is properly distributed on all sup-
Exhaust systems should be inspected porting brackets and hangers. If the load
ak. is not properly balanced reposition pipes
periodically for restrictions and leaks. Restric-
at connecting joints.
tions such as kinked or crimped pipes result
in harmful back pressure. while exhaust leaks When the clearance and balance are
create unwanted noise and a oanger of correct. tighten all bolts and clamps.
posonous gas seeping up into the cab working from front to rear. Note when in-
Restrictions are caused by pipes being struck stalling the exhaust pipe to the manifold.
Leaks are usually caused by always use new packing and new nuts or .45

1 loose clamp assemblies bolts Be sure to clean the manifold stud

threads with a wire brush before installing
...elective connections between manifold the new nuts
and exhaust pipe. and exhaust pipe and
muffler(s) Alter everything is tightened start the
engine and check the connections for
3 corroded pipes leaks A horizontal muffler installation is
shown in Figure 7-100 and a verticle muf-
4 punctured muffler. fler installation in Figure 7-101 Note how

69
4.
 ENGINES 7:59

the clamps and support brackets are

positioned to ba:ance the weight of the
pipes and muffier(s) Courtesy of General Motors Corporuon

(7-100)
HORIZONTAL MUFFLER INSTALLATION

-5255

Ll ...._ALL CLAMPS t2 I? PT L0

Either a curved end or a

rain-cap shoul': be installed
on the end of the pipe

MUFFLER-5225 MUFF LER-5225

RN EXTENSIOU
50209

RN PIPE-5245
MUFF LER INLET WEAN
CLAMP-5A281 SA212

ENCORE PIPE OREf/-

914ACKET11291 \JJ
MI" 21t2
5E20/

Courtesy of Ford Motor Co

UOOLT -5A720 CONNECTOR

CLAMP 6270 VINO
BRACKET -5A245 WAS14,44111742
MUFFLER OAST PIPE
LI4 5245 uv7 -349e7 S2

(7-101) Typical Heavy Trlc MAI Exhaust SystemL, LT-, LNT -9000 with V-903 Dual Vertical Mufflers Shown Others
Similar

70
7:60 ENGINES

QUESTIONS EXHAUST SYSTEM

1 Besides carrying away exhaust gases and
heat a muffler must'
(a) increase horsepower
(b) help control engine temperature
(c) muffle engine noise
(d) all of the above
2 Back pressure causes.
(a) incomplete cylinder scavenging
(b) loss of power (four horsepower for
every two P.5.1. back pressure)
(c) increased fuel comsumption
(d) a. b and c are all correct
3 Usually muffler volume is equal to
times engine displacement.
(a) 6 to 8
(b) 4 to 6
(c) 7 to 9
td) 2 tr., 4
4 Why are gradual bends better than sharp
bends in an exhaust system?
5 What is the danger of leaks in exhaust
piping'
6 From a safety point of view, what is the
most important precaution to take when
running an engine indoors?
7 How can you check exhaust pipe con-
nections for leaks,

71
 ENGINES 7:61

FUEL SYSTEMS
AIR INLET
The basic purpose of a fuel system is to
ply enough fuel to meet engine speed and
load demands Gasoline, diesel and L.P gas I "- )AT
CHOKE
engines all have a different type of fuel VALVE NOZZLE
system. (OPEN) FUEL INLET

GASOLINE FUEL SYSTEMS

VENTURI FUEL INTAKE
The gasoline fuel system supplies a com- VALVE

bustible mixture of fuel and air to power the

engine The gasoline fuel system has three THROTTLE
Combo/mien
Chamber
basic parts (Figure 7-102): VALVE
(PARTLY ktiake Valve
fuel tank stores gasoline for the engine CL OED)

fuel pump moves the fuel from the tank

to the carburetor
carburetor atomizes the fuel and mixes F
fuel and air in the proper ratio MIX
Poston
FUELAIR
MIXTURE (7-103) ENGINE

Courtesy 01 John Deere Ltd

FUEL PUMP
AND FILTER

Courtesy 01 John Deere Ltd

(7-102)

GASOLINE FUEL SYSTEM

The fuel pump draws the gasoline through a through the narrow neck. and the rate of flow
fuel line from the tank and forces it in to the is maintained) When the air speeds up its
float oharbher of the carburetor where it is molecules spread out and consequently its
stopped. Ti' .1 carburetor is basically an air pressure is reduced For example. air
tube connected to a float chamber that traveling at 14 7 lbs per square inch can drop
operates by a difference in air pressure to 8 passr.g through the venturi This
(Figure 7-103) drop mates a pressure difference between
the carbLretor float chamber and the car-
The pressure difference in the carburetor is buretor nozzle that opens onto the ventun
created when air flows through a narrow neck The pressure difference at the nozzle tip
called the venturi. In order to maintain its rate draws fuel from the float chamber and delivers
of flow air traveling through a tube at a given it to the nozzle In the form of tiny droplets The
rate will speed up as it goes through a droplets mix with the air . d vaporize giving
narrowing in the tube (ie.. at the narrowing the air-fuel mixture for combustion.
not as much air can get through. Therefore.
the air must travel faster By speeding up. the
same amount of air per second can travel

72
7:62 ENGINES

The fuel-air mixture must pass a throttle valve 2 Also obtained from natural gas.
before it goes to the engine The throttle con-
trols the amount of mixture going to the cylin- 3 Made up of propane. butane or a mixture
ders. and thereby controls engine speed of the two.

The other basic part of a carburetor is the 4 Vaporizes very easily Remains a liquid
choke which is needed for starting an engine only when under pressure
in cold weather The choke is located in the 5 Liquified by compressing many gallons of
incoming air passage and partially or fully vapor to make one gallon of liquid.
closing it causes a vacuum to form un-
derneath it The vacuum causes the car- 6 Easy to handle and store as a liquid.
buretor to produce a mixture which has a Stored in strong. heavy tanks with
greater percentage of fuel This richer mixture pressure relief valves.
IS necessary because when gasoline is cold it
does not vaporize as readily as it does when 7 Expansive when heated (due to more
it s hot: so. more fuel is needed to supply an vaporization).
adequate amount of vapors Tne choke may 8 Converted to vapor again on way to the
be automatically controlled. opening as the engine.
engine warms up. or it may be manually con-
trolled by the operator. The basic difference in the operations of an
LPG fuel system and a gasoline fuel system is
Of course. actual carburetors are more com- that LPG is vaporized before it reaches the
plex: they will be studied in future training carburetor whereas gasoline is vaporized in
Recommended reading: Chapter 18 and 19. the carburetor.
Automotive Fuel Systems and Automotive
Carburetors. in Automotive Mechanics, Parts Of A LPG Fuel System
Seventh Edition. The LPG fuel system has four basic parts
(Figure 7-104%:
LIQUIFIED PETROLEUM GAS
Pressurized Fuel Tank
FUEL SYSTEMS
Fuel Strainer
Facts About Liquified Petroleum Gas (LP3) Converter
LPG 15 -- Carburetor
1 A by-product of gasoline refining
Het Woe:
From Engine

VapotAir
Mixture
CONVERTER

Vapor

FUEL
STRAINER Vepot
Ligeld
Fuel
Ly < Air
Inteke

Return Nutty
CARBURETOR

FUEL TANK

(7-104) LPG FUEL SYSTEM

Courtesy of John Deere Ltd

73
 ENGINES 7:63

The pressurized fuel tank stores the liquid fuel Advantages and Disadvantages of LPG
under pressure. A space for vapor is left at the
top of the tank. To withdraw LPG from the The advantages of LPG are:
tank two methods are used liquid withdrawal Burns much cleaner than gasoline or
and vapor withdrawal diesel fuel; its exhaust contains less
Most modern systems use the liquid with- carbon monoxide and other harmful
drawal method The fuel is drawn from the emissions. For this reason it is used in
tank under pressure as a liquid and then machines such as fork lifts that operate
vaporized. The vapor withdrawal method is in warehouses or other closed en-
normally used only for starting when the vironments.
envie is cold and hasn't enough heat to con- Cheaper fuel especially where close to
vert liquid fuel to vapor. Vapor is drawn off the source.
top of the tank to provide vaporized fuel for
start up. Once the engine is warm, the fuel Less oil consumption due to less
system is switched to liquid withdrawal. engine wear.
The fuel strainer cleans the liquid fuel. it nor- Reduced maintenance costs, longer
mally has a solenoid which permits flow only engine life between overhauls.
when the engine ignition is turned on.
Smoother power from slower, more
The converter changes the liquid fuel to vapor even burning of LPG fuel.
by warming it and lowering its pressure.
The disadvantages of LPG are:
The carburetor mixes the fuel vapor with air in
Equipment costs are high. Bulk storage
the proper ratio for the engine.
and carburetion equipment are costly.
Comparing LPG and Gasoline Fewer accessible fueling points. Not
t. Both propane and butane produce slightly
many LPG filling stations.
less heat per gallon than gasoline Harder to start engines on LPG in cold
However. LPG has a higher octane rating weather (0*F or below) because oil on
which means that the compression ratio of the cylinder walls remains undiluted
LPG engines can be raised to offset the and makes the engine harder to turn.
heat losses.
2. LPG burns slower than gasoline because
it ignites at a higher temperature. For this
reason. the spark is often advanced far-
ther on LPG engines.
3 More voltage at the stark plugs may be
needed for LPG engines than for gasoline.
4. LPG engines do not require as much heat
at the intake manifold as gasoline models
because LPG will vaporize at lower tem-
peratures The result: less heat is wasted
and more heat goes into engine power.

74
 7:64 ENGINES
INJECTION NOZZLES

COMBUSTION]
CHAMBER
8

1 t_

FUEL TANK

%-0*--"--

INJECTION
PUMP

5
is HIGH PRESSURE
LOW PRESSURE
TANK PRESSURE r
FUEL FILTERS
FUEL
TRANSFER
PUMP
A 1"/
Courtesy 01 -Porn Deere Ltd
(7-105)
DIESEL FUEL SYSTEM
(DISTRIBUTOR TYPE SHOWN)

DIESEL FUEL SYSTEMS Fuel either flows by gravity pressure from the
fuel lank to the transfer pump or it is drawn
The prime lob of a diesel fuel system is to in- from the tank by the transfer pump From the
ject a precise amount of atomized and
transfer pump fuel is pushed through filters
pressurized fuel into each engine cylinder at and clea.ed (It is very important that diesel
the proper time
fuel be absolutely clean so that the closely fit-
Combustion in the diesel engine occurs when ted parts in the injection systeo are not
this charge of fuel is mixed with the hot com- damaged The fuel then travels to the in-
pressed air that ignites the fuel. jection pump where it is metered and highly
pressurized and then delivered lo each of the
The major parts of the diesel fuel system are injection nozzles The injection nozzles
(Figure 7.105)* atomize the fuel and spray it into the com-
Fuel tank stores fuel bustion chambers

Fuel Transfer Pump pushes fuel Function Of Fuel Injection

through filters to the injection pump.
The Diesel Fuel Injection must.
Fuel filters cleans the fuel.
Supply Fuel The fuel injection system
Injection Pump times, measures and must supply the exact amount of fuel to
delivers fuel under pressure to the each cylinder on each cycle.
cylinders
2 Timed Fuel Celivery Fuel delivered too
a governor controls engine speed. early or too late during the power stroke
causes a loss of power Fuel must be in-
Injection Nozzles atomizes and jected into the cylinder at the instant
sprays fuel into the cylinders. maximum power can be realized.

75
 ENGINES 1:65
3 Control Delivery Rate Smooth precaution against dirt. the fuel pick up
operation from each cylinder depends on line will have a coarse filter such as a
the length of time it takes to inject the screen at the fuel entry point
fuel Fuel must be injected at a rate that
controls combustion and cylinder 6. Diesel fuel systems generally have a
pressure. The higher the engine speed the return line as well. This line returns at the
,,.ster the fuel ust be infected. opposite end to the outlet so that any en-
trapped air can escape.
4 Atomize Fuel The fuel must be
thoroughly mixed with the air for complete 7. Baffies to strengthen the tank and prevent
combustion. For this reason the fuel must sloshing of the fuel.
be broken up into fine pa. tides. 8. A gauge or some means of checking the
5 Distribute Fuel The fuel must be spread fuel level.
evenly in the cylinder to unite with all the 9. Dual tanks have connecting lines and
available oxygen This makes the engine possibly a three-way valve to switch from
tun smoothly and develop maximum one tank to the other.
power
Gasoline fuel tanks in small vehicles are
There are a number of different fuel injection usually made of tight gauge metal pressed
systems. but they all must perform these five into shape anL treated to prevent rusting. Fuel
basic :unctions Diesel fuel supply systems tanks for larger vehicles, whether for gasoline
will be dealt with in greater detail at a later or diesel. are made of much heavter gauge
d ale metal. and are rolled and welded with stam-
ped ends. These tanks are also treated in-
BASIC COMPONENTS OF GASOLINE, ternally to prevent rusting
DIESEL AND LPG FUEL SYSTEMS Fuel tanks come in many different sizes and
Following is a closer look al some of the fuel shapes. The tank must be capable of storing
supply components of the three fuel systems
enough feel to operate the engine for a
ft that you are most likely to be in contact with
reasonable length e time. The shape of the
at this level of training. tank is made to conform to the space
avai!able on the machine. A tank can be tall.
short, round. square, whatever shape that will
Fuel Tanks
fit into the allotted space.
Fuel tanks for gasoline. LPG and Diesel all
have the same purpose to provide a safe
method for storing fuel. The location, size and
tank material for the three systems, however.
will vary
Gasoline and Diesel tanks generally have the
following features'
1 A drain plug or drain cock on the bottom
of the tank which allows water or
sediment to be periodically drained.
2 A shut-off valve on the outlet line
3 A idler cap that is twist sock or threaded
4 A vent mechanism It may be built into the
filler cap or be located separately The
vent allows air to enter the tank to replace
the space of the fuel that is drawn out.
thus preventing restriction of the fuel llow
or a vacuum in the tank
5 An outlet pine is raised slightly from the
bottom of the tank to prevent dirt or water
getting into the fuel 1:ne. As an added

76
 7:66 ENGINES

LPG Tanks
An L.P gas fuel tank must be strong and
heavy to withstand the pressure of its fuel.
The fuel tank is never filled completely full of
liquid fuel (usually to 80%) because room
must be left for vapors and expansion. The
tanks require special equipment to fill them
Two types of tanks are shown in Figure 7-106.
a vapor withdrawal tank and a liquid with-
drawal tank

LOW-PRESSURE ENGINE
INTAKE MANIFOLD
PRESSURE REGULATOR
PRESSURE RELIEF VALVE GAUGE

VAPOR LINE
ADJUSTING
VALVE
Er; FILL VALVE 0
r
VAPOR

HIGH-PRESSURE
FUEL REGULATOR CARBURETOR

HOT WATER FROM ENGINE

RETURN WATER

LPGAS SYSTEM USING VAPOR WITHDRAWAL

PRESSURE V4POR VAPOR

RELIEF LINE RETURN LIQUID LINE STRAINER ENGINE
VALVE 80 ('; VALVE VALVE VALVE VALVE INTAKE
FILL LOW-PRESSURE MANtFOLO
FILLING VALVE REGULATOR
VALVE

VAPORIZER

VAPOR HOT WATER

FROM ENGINE
FUEL
--111-=,/

HIGH-PRESSURE r_-11
RETURN CARBURETOR
FUEL TANK REGULATOR
WATER

LP --GAS SYSTE" 'SING LIQUID WITHDRAWAL

Courtesy Jonn Deere Lid
(7-106)
LPG FUEL SYSTEM

77

mri
 ENGINES 7:67

Fuel Filters Filters are rated according to the degree to

which they filter out particles Filtration
Contamination of fuel can be a major cause of degree is usually measured in microns. One
wear to internal engine parts that eventually micron is approximately .00004 inch or one 40
leads to engine failure Fuel filter must clean millionth of an inch. To get an idea of how
the fuel before it gets into the carburetor in small a micron is it would take 25.000 microns
gasoline and L P gas engines. or into the in- laid side to side to make up an inch. The
jection pump in a diesel engine smallest particles that can be seen with the
unaided eye are about 40 microns. Since
Types Of Filters some of the finer fuel filters (diesel) are rated
Filtration removes suspended matter from the at two microns. many of the particles they
fluid Some filters will also remove soluble Im- filter out are invisible.
purities Fuel filters in gasoline engines are usually in-
Filtration can be done in three ways. corporated into the fuel pump. as below:
straining FUEL
STRAINER
absorption
magnetic separation FUEL BOWL

Straining is a mechanical way of filtering

(Figure 7-107). A screen blocks and traps par-
ticles larger than the openings. The screen
may be wire mesh for coarse filtering or paper
or cloth for liner filtering.

I'll

II
HAND PRIMER ROCKER
LEVER ARM
II
Y"6 (7-108) Courtesy of John Deere Ltd

1 111
la The filter acts as a water trap and provides a
place where sediment can settle out of the
fuel. Sediment build up can be examined
1111 through the glass bowl and should be cleaned
I11 II when necessary. In addition to this filter many
STRAINING ABSORPTION gasoline fuel systems use an in-line-filter be-
(7-107) tween the pump and the carburetor (Figure 7-
Couruisy of John Deere Ltd
t09).
WITHOUT VAPOR RL l'URN LINE
Absorption is a way of trapping solid particles
and some moisture by forcing these con-
taminants to stick to the filter media cotton
waste. cellulose, woven yarn. or felt (Figure 7- rFilter
107).

Magnetic Separation is a method of removing Fuel Pump

water lrom fuel. A paper filter is treated with Carburetor
Co
chemicals that cause any water in the fuel to
separate and drip into a water trap (The filter Fuel Tank
also rerno%.es solid particles by one of the Filler
other methods of filtration ) (7-109) Courtesy of Font Corpnrat!on

78
7:68 ENGINES

An in-line fuel filter usually has a pleated Another location for a filter is at the inlet of the
paper filtering element (porous bronze or ca-turetor The filter is threaded into the inlet
ceramic is also used) enclosed in a sealed and has a tube connector at the other cid.
plastic container In-line filte, cartridges are This filter generally uses a screen as a
throw-away items replaced after so many filtering element.
hours of service (Figure 7-110).
L.P. gas systems use a fuel strained (Fig..re 7-
111) located between the fuel tank and the
converter.

The fuel strainer has two functions:

1. Strains fuel to clean it.
2. Shuts off fuel when system is not
operating.
The strainer has stages including a screen. a
felt filter, a chamois filter (to remove water),
and another screen. A sediment bowl with a
drain plug collects the foreign matter.
The shut-off is an electrical solenoid coil
generally referred to as a filter lock. When the
engine ignition is turned on, the solenoid
magnetizes the va;ve plunger ar.1 opens it,
allowing fuel to flow. When the ignition is
turned off or fails, the valve closes
automatically. Pressure of the fuel holds it
tightly on its seat.

Diesel Fuel Filter

Although important to gasoline engines. fuel
17-110) TYPICAL IN-LINE FILTER CARTRIDGE filtration is even more important to diesel
Courtesy of Frain Corporation operation because:
1. Diesel fuels tend to be impure.
2. Injection parts are precision made and
SPRING dirty fuel will damage them.
Because filtration is so important to a diesel
SOLENOID fuel system. the fuel will be filtered not once
COIL
but several times. A typical system like the
one in Figure 7-112 has three progressive
FUEL
VALVE stages of filters. a primary filter. a secondary
OUT
PLUNGER filter and a final stage filter.

FILTER
ELEMENT

Courtesy of John Deere Lid

79
 ENGINES 7:69

INJECTION NOZZLES
or Compressed._
So Hot That
Fuel Ignites :
hen Intectediit

FUEL TANK
5---?

INJECTION
PUMP

(7-112) FUEL
i
DIESEL FUEL SYSTEM TRANSFER
FUEL PiL1ERS PUMP
Courtesy of John Deere Ltd

Primary filters are generally a combination of

a coarse filter that removes large particles
and a water trap: secondary filters are finer
filters that remove most small particles; final
stage filters are very fine (rated as low as two
microns) and remove tiny. invisibLt particles.
Fuel will Pass through all three filters before
reaching the injection pump. Note in the r;\
diagram the drain screws at the bottom of V) FUEL (3)
each stage filter. OUTLET INLET =,
Transfer Pumps
INLET
OUTLET
Gasoline and diesel fuel systems generally VALVE
VALVE
require a fuel supply or trunsfer pump to move
the fuel from the tank to the engine. The most
common type of pump is the mechanical
+o
diaphragm pump which is found on gasoline DIAPHRAWA
and diesel engines. There are also. electric. ENGINE
SPRING CAM
gear and piston transfer pumps. Figure 7-113
illustrates the operation of a typical
0
mechanical fuel pump ROCKER
PULL ARM
ROD

(7-113)

Courtesy of John Deere Ltd

80
7:70 ENGINES

The pump operates as follows' 2. Keep the line connectors tight. but not too
tight Tighten the connectors until snug,
Power is applied to the pump rocker arm at (1)
but don't strip the threads. To avoid ben-
by an eccentric (an offset disc) on the engine
ding the lines, use only one hand with two
camshaft As the camshaft rotates. the ec- wrenches for final tightening, as shown in
centric causes the rocker arm to rock back Figure 7-114.
and forth The inner end of the rocker arm is
Asss#01111
linked to a flexible diaphragm located be-
tween the upper and lower pump housing. As
the rocker arm rocks. it pulls the diaphragm
A
down. and then releases it A spring located
under the diaphragm forces it back up. Thus
the diaphragm moves up am down as the
rocker arm rocks.
When the diaphragm is pulled down. a
vacuum or low pressure area is created above
the diaphragm. This causes atmospheric
pressure in the fuel tank to force fuel into the
pump at (2) The inlet valve (3) opens to admit
fuel into the center chamber (4).
When the diaphragm is released. the spring
1/.4.17e2i
forces it back up. cau sir g pressure in the area "'
above the diaphragm. This pressure closes
the inlet valve and opens the outlet valve (5).
forcing fur! from the pump through the outlet e
(6) to the carburetoi.
Y
If the needle valve in the float bowl of the car-
buretor closes the inlet so that no fuel can en-
ter the carburetor. the fue! pump can no
longer deliver fuel. In this case. the rocker (7-114)
arm continues to rock but the diaphragm TIGHTENING LINE CONNECTIONS TO AVOID
remains at its lower I: nit of travel so the BENDING THE LINES
spring cannot for- r th, . aphragm up. Normal (FINAL TIGHTENING SHOWN)
operation of the ro .esumes as soon e the Courtesy of John Deere Ltd
needie valve in the float bowl opens the 'met
valve. allowing the spring to force the
diaphragm up 3. When replacing a fuel line. be sure to use
an identical line in size. shape and Iencth.
The inside diameter is very critical with in-
HIGH PRESSURE FUEL LINES jection lines.
AND FITTINGS
FUELS
Some diesel fuel systems have a bank of pum-
ping units in one housing and require high COMPRESSION AND FUELS
Pressure lines to deliver the metered and
pressurized fuel to she injectors. Special thick When discussing fuels. the term compression
walled tubing and fittings are required to ratio often comes up. Corm:hes:4°n rally. as
withstand the extremely high pressures. Care stated earlier. is the relation between tne total
must be used not to bend or kink riese lines volume inside the engine cylinder when the
and not to cross thread the fittin!..,s when piston is at its greatest distance from the
removing and installing them. cylinder head. compared to the volume when
the piston has traveled closest to the cylinder
Preventive Maintonanco Sarvice 0 n Fuel head.
Lines an:s' Fittings
The type of fuel an engine uses is directly
1 Periodically inspect the fuel I nes for related ) the engine's compression ratio.
loose connections. leaks. or kr KS. Each fuel has its limits on how much it can be
compressed and still burtI properly
 ENGINES 7:71

1 Kerosene or distillate. when used in a Fuel knock is a serious problem because it ;s

spark ignition engine, operates best at hard on valves. pistons and bearings and
about a 4 to 1 compression ratio causes a loss of power Tests have found that
even a very light knock, one that probably
2 Gasoline operates at a 7 or 8 to 1 com- wouldn't sound harmful. increases the wear
pression ratio. on the top piston ring about four times.
3 L P gls has an 8 5 or 9 to 1 compression The octane rating of a gasoline is a measure
ratio of the gasoline's antiock properties. The
4 Diesel fuel operates usually at about a 16 higher the octane rating, the less tendency
tc' 1 compression ratio. although some the fuel has to knock.
die:PI engines can have 3 ratio as high as The names premium and regular are rough
20 to 1. comparative measures of octane ratings
Gasoline fuel has certain characteristics that 1. regular 88 to 94 octane
make a gasoline engine run efficiently. The
same can be said of diesel fuel and L.P. gas. 2. premium approximately 100 octane
As well, there are different grades or qualities
of ;nese fuels. Below is a discussion of some Premium. h;gh octane gasoline is made for
of the basic characteristics and qualities of ube in gasoline engines that have a higher
gasoline. diesel and L.P. gas fuels. than rormal compression ratio. Most gasoline
engines today, however, are built to run on
GASOLINE regular gas.
What ;s the result of using premium gasoline
Octane Rating on an engine designed to use regular?
To understand octane rating, you have to Premium grade gasoline can be use 'Iut
know what engine knock is. The following there is usually no advantage sine t ost
diagram illustrates how knock occurs in a engines haven't a high enough compression
gasoline engine. ratio to utilize the benefits of the higher oc-
tane rating. Premium in this case is a waste of
money. The best policy is to use an octane
rated gasoline that matches the octane
requirements of the engire.

1 Spark Begins Fuel-Air

Mixture Burning
1 0
2 Plarrie Advances
Smoothly. Ltorn-
1 11 1

3 EndCharge Suddenly
Self Ignites With
pressing and Heating Violence. Producing A
End-Charge Knock, Knocking And
Compression Ratio
Cenetcbsy of 1.1ho 04x..6 Ltd Are Direotty Related
The Higher The Com-
(7-115) pression The Greater
Likelihood The
Gasoline Will Knock

82
 7:72 ENGINES

Volatility and the time it begins to burn This delay is

called the ignition delay period The delay
The gasoline property mr important in period is important because if it is too long
engine starting is volatihttendency to
the fuel, when it does start to burn. will burn
evaporate) If volatility is too low. insufficient explosively causing engine knock Cetane
vapor may be drawn into the cylinder to allow
number measures the ignition delay period.
easy starting in cold weather Warm-up will the higher the cetane number the shorter the
also be slow On the other hand, a gasoline period
with too high a volatility is apt to cause car-
buretor icing or vapor lock under certain at- The speed of an engine prescribes the cetane
mospheric conditions number that the engine requires. Diesel
Oil companies change the
engines whose rated speeds are below 500
volatility of RPM are classed as slow speeo engines, from
gasoline with the seasons. In summer they 500 to 1200 RPM as medium speed. and over
produce a gasoline with low volatility since 1200 RF-M as high speed. Cetane numbers of
the warm temperatures aid in vaporizing the fuels readily available range from 40 to 60
gasoline In winter. on the other hand, they with values of 45 to 50 most common. These
produce a high volatility gasoline so that it celane values are satisfactory for medium and
will vaporize more readily in the colder tem- high speed engines, but low speed engmcs
peratures For this reason if a summer supply
may use fuels in the 25 to 40 octane number
of gasolle is held over to winter, difficulties range
in engine starting will probably resu.t.
It is interesting to note that the octane rating
s Gasoline Additives of gasoline and the celane rctrig of diesel
fuel mea-gire opposite fuel qualities Figure 7-
Additives are put into gasoline to improve its 116). A high octane rating means that the
performance and storage life Some of the gasoline has a low tendency to combust spon-
main ones are taneously By c.mtrast. a high cetane number
i Antiknock components to increase the means that the diesel fuel will combust
octane rating quickly and spontaneously
2 Alcohol anti - freezes to prevent any water
in the gasoline from freezing and to
GASOLINE DIESEL FUEL
prevent ice-plug formation (MUST BURN FAST)
(MUST BURN EVENLY)
3 Anti-icers to Prevent the carburetor throt-
tle plate from icing
4 Detergents to clean the carburetor and V V
keep it free of nisi. OCTANE NUMBER CETANE NUMBER
5 Anti-oxidenis to improve storage stability
and ratard gum formation
MEASURE OF FAST.
Phc...zntiortis compounds to minimize spark MEASURE OF ABILITY SPONTANEOUS
plug fouling and surface ignition TO RESIST DETONATION COMBUSTION

7 Metal deactivators to protect the gasoline

against harmful metals that may get into
the gasohne OPPOSITES

DIESEL FUEL (7-116) OCTANE AND CE.rANE NUMBERS

ARE OPPOSITES
Diesel fuel is made by distilling crude oil Just Courtesy of John Deere Ltd
as the octane rating is probably the most im- An important difference exists when using oc-
portal', characteristic of a gasoline. the tane and cetane numbers to Judge the quality
cetane number the important quality of the fuel. Theoretically the higher the octane
01 a diesel fuel Celane number is a measure rating the better the fuel. assuming of course
of the way the fuel .gnites in the combustion that the engine can take advantage of the
chamber In a diesel engine there is a slight high octane fuel by increasing the com-
delay between the time the fuel is injected pressing ratio or by super-charging the

83
4,
 ENGINES 7:73
airifuel mixture The same is not true of the LPG
cetane number Too high a cetane number
may lead to incomplete combustion and As stated earlier LPG can be all propane. all
exhaust smoke if the ignition delay period is butane. or a mixture of the two Today.
too short to allow proper mixing of the fuel however ' °G is usually all or mostly propane
and air within the combustion space LPG. gasoline. has an octane rating:
propane and butane 96. The high oc-
There are two classes of diesel fuels. No. 1-0 tane ratings ..PG make it suitable for high
au.d No 2-D These classes set standards for compression engines LPG does not come in
fuel characteristics such as cetane number, different grades or qualities
volatility. viscosity. pour and cloud point. car-
bon residue. sulfur content and others The STORING FUELS
numbers 1 and 2 do not mean that No. 1 is a
higher grade than No 2: both are of good There are two main areas of concern when
quality but each has characteristics that are storing fuel:
suitable for different engines and operating protection of fuel quality
conditions Some manufacturer will recom-
mend using either 1-0 or 2-0 depending on safety
working conditions For example, the table on
diesel fuel usage in Figure 7-117 is taken from STORING GASOLINE
a John Deere Ltd tractor operator's manual
Three conditions must be controlled to Mtn-
Ambient Diesel Fuel lain satisfactory supplies of gasoline:
Type of Engine Air Grade
Service Temperature No
Control loss through evaporation.
Avoid gum deposits in gasoline.
Light load low speed Above 80 F 2-D
considerable idling Below 80 F 1-D Protect gasoline from water and dirt
Intermeoiate and heavy Above 40 F 2-0 Controlling Evaporation Loss
load' high speed. Below 40 F 1-D
minimum of idling Figure 7-118 illustrates the effects of coloring.
shading. and a pressure vacuum relief valve
At altitudes above All 1.0 on gasoline evaporation.
5 000 feet

rlesy of John Deere Ltd (7-117)

Courtesy of John Deere Ltd

,yr

PRESSURE.
SUOMI;
RELIEF
VALVE

r:01
A Red Tank Exposed To Sun's Heat C While Tank Protected By A Shade
White Or Aluminum Tad &posed To Sun's Heat D While Shaded Tank Equipped With A Pressure-Vacuum
Relief Valve
17-118) SUMMER EVAPORATION LOSSES FROM 300-GALLON GASOLINE STORAGE TANKS

84
7:74 ENGINES

Although this test is conducted under summer adding fuel to a tank or taking it out No mat-
temperatures. similar res-Its would occur In ter how careful you are. though. water and dirt
winter because winter fuel. as was described will still enter the tank Condensation forms
earlier, is more volatile and evaporates on the inside of the lank and the moisture
quicker drops to the bottom of the tank because water
IS heavier than gasoline. The more the tem-
If an underground tank IS used the tem- perature of the tank varies. the greater the
perature of the stored fuel remains low amount of condensation. Thus the same
enough all through the year so that precautions that are taken to keep
evaporation losses are small evaporation down will also limit condensation.
Avoiding Gum Deposits Water must be occasionally drained or pum-
ped out of the tank
Gasoline will oxidize and form gum deposits if
kept for king periods. (311 companies add an Like condensation dirt in the fuel will settle to
inhibitor that will protect the fuel le- six the bottom of the tank. This sediment must oc-
months to a year under normal storage con- casionally be drained or pumped out of the
ditions. but the interval is greatly reduced if tank See the next section on storing diesel
the gasoline is exptsed to sunlight and to fuels for illustrations of pumping and draining
high storage temperat.ires To limit gum for- tanks
mation avoid storing more gasoline that you
can use conveniently in a period of about 30 Safety
days Gum deposit is less of a problem with Fire prevention regulations regarding tank
underground tanks since the fuel remains placement are shown in Figure 7-119. The
cooler distance that the tank must be away from a
building IS intended to protect the building in
Protecting Gacntine From Water and Dirt
case of lire
Contamination
Practice strict habits of cleanliness when
ABOVE GROUND
TANK

VENY

4031
AINIAllt`

(7-119)
BUILDING"' Jai
SAFE I.00ATION OF GASOLINE STORAGE
TANKS IN RELATION TO BUILDINGS
UNDERGROUND
TANK Courinsv of John 0(.4 br ,.! LW

,l
..L'4
iiie.,

85
 hours before fuel is drawn from them. Also
don't let water collect on lop of drums (Figure
Evaporation during storage. whether above or 7-120) because
below ground. is not rapid enough with diesel
fuel to be a concern More important with waler resting on the top tends to rust the
diesel fuel is to drum.
1 keep it free of dirt and water as fuel is drawn from the tank. water may
be drawn through the air vent directly into
2 prevent gum deposit the fuel supply.
Keep Fuel Free Of Dirt and Water NOZZLE
CAP
It is important that all fuels be kept free of dirt
and water. but it is especially important with
diesel fuel The reason' the fuel injection
system on a diesel engine is fitted with parts
that are held within millionths of an inch
clearance Very fine dirt particles soon ruin
the parts and cause an expensive repair job.
Water. even extremely small amounts. causes
corrosion which ruins the high-polished Sur-
faces of the injector nozzles. Ad operator's
manuals for diesels emphasize the im-
portance of clean fuel
Water is ahout the same weight as diesel fuel
so it settles out very slowly For this reason Dirt particles may come from several different
allow 24 hours for water and dirt to settle to sources. Some particles may be present in the
the bottom of the storage tank after it has fuel when delivered. but dirt is far more likely
been refilled Use two storage tanks: wr en to come from carelessness or improper
one is refilled. the other can be used to st.oply storage Some rules for preventing dirt in the
fuel If you have only one storage tank. be fuel supply are:
sure to fill your machine's fuel tank before the Don t use an open container to transfer
supplier refills the storage tank Another good fuel from the storage tank to tne machine
policy is to fill engine Tanks at the end of each tank. it will greatly increase the chance of
day to reduce overnight condensation in dirt entering the fuel tank. To transfer fuel.
them equip aboveground tanks with a pump and
If drwris are used for storing fuel. be sure that hose (Figure 7-120) or a gravity hose
they are mounted rigidly in place Any han- (Figure 7 -121). Be sure to cap the end 0.
dling will ream the dirt particles and water the hose nozzle while the hose isn't in
from the bottom of th?. tank with the fuel use
When portable drums are used for re:ueling in
the held. be sure they are in place at least 24
7:76 ENGINES

2 Don't store diesel fuel in a galvanized Preventing Gum Deposits

tank A galvanized tank is satisfactory for
gasoline. but when diesel fuel is stored in Diesel fuel. like gasoline. contains a gum
8t. the fuel reacts with the galvanized inhibitor which retards the formation of gum
finish causing powdery particles to form. and varnish for about three months Keeping
These particles soon clog the fuel filters aboveground tanks shaded will help to limit
on a diesel engine. Use steel tanks to gum deposits.
avoid this problem Diesel fuel may be stored longer than
3 Don't use a tank formerly used for gasoline: while gasoline should not be stored
gasoline to store diesel fuel. Fine rust and longer than 30 days. diesel fuel may be kept
dirt particles that settled out of gasoline for about three months.
and accumulated on the bottom of the
tank. mix readily with diesel fuel and may Safety
remain suspended in it until drawn from Although diesel luel is safer than gasoline.
the tank the safety precautions that apply to gasoline
4 Don't let the suction pipe to the fuel pump should also apply to diesel fuel
extend to the bottom'of the storage tank.
This permits the pump to pick up water
and sediment that has settled out of the PITCHER
PUMP
fuel The end of the pipe should be three
or lour inches from the bottom If possible.
slope the tank away from the pipe or
outlet valve
5 Always drain the storage tank before
refilling and clean the tank twice a year
otherwise the dirt and water residue may
rise high enough to be drawn out with the
fuel (Figure 7-122)

(7-123)
USING HAND PUMP 10 CLEAN
DIRT AND WATER FROM
UNDERGROUND STORAGE TANK .
P.

WATER SEDIMENT
coorti, of John Courtesy of John Deere Ltd
Deem Ltd

(7-122)

SEDIMENT, WATER
AND FUEL

1 DRAIH SEDIMEHT, WATER AND 2 FLUSH TANK WITH CLEAN

FUEL FROM TANK DIESEL FUEL

87
 ENGINES 7:77

STORING LPG
Since LPG is stored in pressurized tanks.
there are no problems in maintaining the
quality of the fuel. nor problems with the fuel
evaporating. Also the fuel will not change
chemically. during storage. Therefore. LPG
can be stored for as long as necessary.
Safety With LPG
1 Remember that LPG is always under
pressure and the fuel supply components
must be leak proof
2 Never smoke or use any flame near the
fuel
3 Fill holes and low spots in the vicinity of
the storage Gas fumes that leak from the
lank or escapes while filling the machine
are heavier than air. The fumes will ac-
cumulate in low spots and become a fire
hazard
Large storage tanks for LPG like those
gasoline ano diesel fuel have to be located at
a safe distance from buildings and from other
fuel tanks. In Figure 7.124 note the posts
protecting the pump and hose connections.

20'
MINIMUM
DISTANCE
FROM OTHER
FUEL. STORAGE

\
FUEI. PUMP
\U V.....if

POSTS
(Prated Tank mud Pump
From Acestlental Bumpata)

(7-124) SAFE LOCATION OF LP-GAS STORAGE TANKS IN RELATION TO

BUILDINGS AND OTHER FUEL STORAGE
COls nosy 01 J.11:1 Deere Ltd

88
7:78 ENGINES

PREVENTIVE MAINTENANCE SERVICE OF 4. Always install new gaskets.

FUEL SYSTEMS
5 On diesel fuel systems. fill new filter car-
DAILY WALK AROUND CHECKS tridges or filter housings with fuel before
installing them: this will lessen the
The following checks on the fuel system chance of air oiling into the system and
would be made as part of the daily walk making the engine difficult to start. Diesel
around check and at any time that scheduled fuel systems must be completely free of
maintenance is done on the fuel system air to function properly
1 Look for leaks in fuel lines. in the tank. at 6 Bleed the fuel system of air. Bleeding is
connections and generally throughout the described later in this section
system Also check for damaged or kinked
fuel lines. 7 After installing the filler. start the engine
makingabsolutely sure that there are no
2 Check for water or dirt accumulation in leaks
the primary filter glass bowl (if equipped)
and clean the bowl if contaminants are
found On primary filters that don't have a
glass bowl. open the drain momentarily to
check for water or dirt
3 Momentarily open the fuel tank drain to
check for contamination
4 Remove the fuel tank filter cap ^lean the
cap and the area around it

CHANGING FUEL FILTERS

Fuel filters are changed at intervals specified
by the manufacturer The iNo main types of
titter elements are
1 cartridge filters installed in a case or
housing
2 spin dn. Irow away filters
tAinter traps with washable elements are also
used on sow.- s _ ;stems
3elow are good practices when cha...4ing
filters These practices apply to ffIters for both
diesel and gasoline fuel syste
1 Always be aware of potential fire hazards
when working on fuel systems especially
.vith gasoline anrt take the necessnry
precautions
i II me system nas a shut -Ott on the wet
tanlasi or fuel line close it before
removing the filter
3 Since clear linas aro of utmost im-
portance when working fuel sys'4ems
fpaitic Wady on Jiesels) thoroughly clean
the entire area around a filter before
removing ii Also clean the inside of the
nousing on cartridge briers. and make
sure that thP gasket sealing surface on
spin on filters is absolutely clean 8:3
 ENGINES 7:79

Figures 7-124, 7-125, 7-126 give examples of

typical fuel filter changing procedures taken
from service manuals.
Water Trap With Washable Parts
(Figure 7-124)
FUEL SYSTEM FILTERS Service When Fuel Pressure Gauge Registers OUT
with Engine Running.
Primary Fuel Filter

(7-124)

ALLELIEFAMP` Courtesy of
,paiww-- Caterpillar Tractor Co

1)
I Close fuel supply valve 2 Remove bowl and element
3 Wash element and bowl in clean
kerosene
4 Install elemen and bowl
5 Open fuel valve and start engine
If Net pressure gaircie still registers
OUT change final luel Met
Throw Away Filter (Figure 7.125)
Final Fuel Filter
cr,

(7-125)

1 Coortrmy of
(...arerplioar tr.octor rLo
'u
I
fidagmog.

close fuoi supply valve and 2 Clean filter base gasket surface 4 Open fuel 'valve and
rPrnove filter Lubricate new fillet gasket with prime fuel system
dean beset fuel
5 Start engine rind check
3 Install new filter Tighten tiller too leaks
until gasket surface conta:ts
base then tighten additional 1.2
turn

90
7:80 ENGINES

Cartridge Filter (Figur& 7-126) (7-127) Priming Fuel System

Remove drain plug from bottom of filter
case and dram contents
2 Loosen bolt at top of fuel filter Take out
dirty element. clean filter case and install
a new element.

1
. senod.

I Move governor control to off

position Open vent valve.

(7476) INSTALLING 11EPLACSABLE FUEL

FILTER ELEMENT
echotesv Cummins Engine Co

3 Fill filter case with clean fuel to aid in

faster pick-up of fuel. Install a new gasket
in filter head and assemble case and
element T'ghlen center bolt to specified -*-
torque tiO Mr
2 Unlock "riming pump plunger
Bleedirtra A Diesel System and operate pump until. .

Whenever hrixfs are aesconnected. a fuel pump

is changed or new filter(s) are installed, the
fuel system 'III venerally have to be bled or
purged of air Bleeding is sometimes reterred
to as priming
Some fuel systems are easier to bleed than
others Cranking rle engine will purge the air
on one system. whereas another system will
require loosening the injector lines or filter
bleeders and then cranking :he cog'- a. A
third type of system is eouipped with a hand
pump that must be activated to prime the fLel
systair Operating instructions for such a
puv.'p are given in Figure 7-127
3 -low of fuel flam drain line is
free of air bubbles Lock pump
piunger and close vent valve
Colinew ol Tractor Co

91
 ENGINES 7:81

Once the pump has tied the system. start the

engine The ungine may run rough for a little
while until all the air is gone
SERVICING THE FUEL STRAINER IN
A LPG FUEL SYSTF.11A
If the fuel strainer frosts up. its filter element
is probably clogged and needs cleaning
Before attempting to clean the strainer. make
sure both withdrawal valves are closed, the
engine is cold. and the lines and strainer are
emptied of gas To clean the strainer. forst
remove the dram plug and chaan out foreign
matter Follow service manual instruc...ons on
blowing out the strainer and cleaning the
strainer parts
A failed solenoid in the strainer is inoica'oed
when the ignition is turned on and gas fails to
flow to the converter The prob'em is likely a
sticking valve plunger.
1:82 ENGINES

QUESTIONS FUEL AND FUEL SYSTEMS 11 The function of the injection pump in the
diesel fuel system is to:
1 List the three basic parts of a gasoline
fuel system. (a) time the injection and measure or
meter the fuel
2 Besides metering the fuel a carburetor
(b) pressurize and deliver the fuel to
(a) atmoizes the fuel each cylinder
(b) mixes fuel and air in the proper ratio (c) both (a) and (b) are right.
(c) distributes this fuel-air mixture in to 12. What is the difference between an LPG
the manifold fuel tank and a gasoline or diesel tank?
(d) all of the above
13 The degree of filtration of a filler is
3. A carburetor works on the basic prin- measured in.
ciple of:
(a) Protons
(a) difference in power
(bi Electrons
(b) difference in pressure
(c) Microns
(C) difference in speed
(d) Neutrons
(d) all of the above
14 When an in-line fuel filter is used in a
A choke valve is required en a carburetor gasoline fuei system. u is usudiiy pidced
to hetve, an the.
(a) increase the power when the engine (a) gas tank and fuel pumps
is hot
(b) carburetor and manifold
(h) increase the power when the engine
is cold (C) fuel pump and air cleaner

(c) clean out the mixture during cold (d) fuel pump and carburetor
starts 15 The filter in a LPG fuel system serves two
(d) give a richer mixture for cold starts purposes. it strains impurities from 'le
5 LF.:..5 is made up of -._.
. or a mixture of the Iwo
fuel and:
(a) pre-heats the fuel
6 LPG will only remain a liquid when it is (b) coois the fuel
(c) shuts off the fuel when the system is
(a) stored outside not operating
(b) stored in large containers (d) stores extra fuel

-
(c) stored under pressure
16 Gave two reasons filtering is so important
(d) stored in a heated area in a diesel fuel system
7 What is the basic difference .1 the 17. A mechanical diaphragm fuel pump
operation o! an LPG fuel system and a opei ales by an arm that ru is on a cam on
gasoline fuel system? the engine's
8. In an LPG fuel system the (a) crankshaft
changes the liquid gas to a vapor
(b) camshaft
9 Why is LPG commonly used in such (c) water pump shaft
warehouse machines as fork lifts'
(d) rocker shaft
10. How does a diesel engine's method of
delivering ;uel to the engine differ from 18 True or False? When replacing fuel in-
that used by a carbureted r soline jection lines, any line size or length will
engine? do provided the connections fit properly.
19 Care must be taken not to
_______ _ fuel line connectors

43
 ENGINES 7:83

20 How does compression rata relate to the 32 What advantage does LPG have over
fuel in engine uses? gasoline and diesel with respect to
storing?
21 Which of the lollowint, fuels is burned E.t
the hig ,est comprelslon ratio/ 33. How far should a pump intake pipe be
from the bottom of a fuel storage tank/
'a) gasol.ne Why/
diesel
34. Briefly list items that should be checked
(c) LPG during a daily p.m. of the machine's fuel
27 What does octane rating refer to in system.
gasoline/ 35 To aid in starting a diesel engine after a
. . '
23 How does low volatility gasoline effect fuel filter change it is a good practice to:
cold starling/ (a) change the filter quickly
24 What does the cetane number refer to in (b) don't shut the engine off while
diesel fuel/ changing the filter
25 List the two main areas of concern when (c) have the fuel tank full before
storing fuel changing the filter
(d) fill the new filter with fuel before in-
26 How does the color of a fuel tank effect stalling it
the loss of gasoline through
evaporation/ 36. Bleeding or priming a diesel fuel system
IS necessary to remove all the
27 When gasoline and diesel fuel are stored in the fuel system after fuel
f Dr long periods of time. they will oxidize lines have been disconnected or a pump
forming deposits. Gasoline should not Or filter changed.
be stored for periods over
Diesel fuel can be stored up to 37. An obvious sign of a clogged filter on an
LPG fuel system is the:

28 How can gum deposits be minimized in (a) engine is hard to start

above ground diesel fuel tanks? (b) engine runs rough
29 How long should you wait before (c) fuel strainer frosts up
drawing fuel from a newly filled diesel (d) engine will miss at high speed
tank or drum/
(a) 5 to 10 minutes
(b) 3 or 4 hours
(c) overnight
(d) 24 hours
30 What is the best policy to follow to
reduce overnight condensation in a
machine s fuel tank?
(a) store the rnachme In a warm place
(b) drain the water trap at the beginning
and end of each shift
(c) fill the tank at the end of each shift
or day
(d) sill the tank before it runs out
31 True or False/ Galvanized tanks are
suitable for storing diesel fuel/

94
7:84 ENGINES

ANSWERS lNTERNAL COMBUSTION

ENGINE
1 heat mechanical
2 (a) air
(b) fuel
(c) combustion
3 It's heated
4 In a vaporized state
5 False Oxygen causes the fuel to burn
6 rotary
7 id) intake. compression. power. and
exhaust
8 to) cycle
9 it>) I -Head

l^ in a two stroke cycle engine. the cycle is

completed during one revolution of the
crankshaft The piston makes two
strokes, one up and one down. In a four
stroke cycle engine, the cycle is com-
pleted during two revolutions of the
crankshaft The piston makes four
strokes. two up and two down.
11 water air
12 1 gasoline
2 diesel
3 LPG
13 In a gasoline engine fuel and air are
mixed in the carburetor and then sent to
the combustion chamber where the mix-
ture is compressed and ignited by a
spark plug In a diesel engine air is com-
pressed in the combustion chamber and
then injected with fuel. The heal of the
compressed air ignites the fuel.
14 To raise the temperature high enough to
ignite the fuel without a spark.

95
 ENGINES 7 :85

ANSWERS COOLING SYSTEM 22. 1. Make sure inlet and outlet valves are
opened.
-9
1. Prevents overheating of the engine.
Regulates temperatures at best level for 2 Check all hoses. fittings and con-
engine operation. nections for leaks.
2. False. 3. Check. and top-up the coolant level.

3. Allows for rapid warming at start-up. 23 . (c) hydrometer.

4 .. heat exchager ... 24. False.

5. (c) Convection.
25. (b) relieve all belt tension.

6. To circulate the water throughout the 26. (a) replace all as a set.
cooling system. 27. 7/16" for one foot. and so half of that
7. . . thermostat. again for one and a half feet.
7/16 + 31I2 = 101/2 or approximately
8. True. 16 16
9. Blower fans are used on slow moving 10" 5"
=
machines because there L. a possibility 16 8
of harmful materials being drawn into the
radiator with rei auction Ian.
10. (b) to increase fan efficieue:y.
11. False.
12. (d) closed by air pressure and opened
by spring pressure.
13. Softens the water (i.e.. removes the
corrosives) and removes the dirt.
14. True. ... corrosive inhibitors.
15. A special element that is compatible with
the anti-freeze needs to be used in the
filter.
16. Leakage.
t7 ... cold
18. 1 They don't give a permanent repair.
2. They will ultimately cause plugging
of the radiator,
19. Accumulation of foreign material in the
core air passages. Regularly check and
blow out the radiator with water or air
1 pressure.
20. Cracked or swollen.
21. 1 Condition.
2. Alignment.
3. Tension.

96

It
7:86 ENGINES

ANSWERS LUBRICATION SYSTEM

1. .... friction ... heat.
2 True.
3. A maximum pressure-relief valve.
4. (b) flit flow end bypass.
5. Pleated paper filter.
6. (d) crankcase.
7. (a) bearings.
8. The filter's bypass valve opens.
9 If the cooler becomes clogged or there is
too much internal resistance within the
cooler on a cold start-up. the pressure
differential valve opens allowing oil to
still reach the bearings.
10. If the blow-by gases in the pan are not
vented. they will build pressure and
cause the front and rear crankshaft seals
to leak. Also. if not vented the blow-by
gases would contaminate the oil.
11 Base stock oil fortified with additives to
provide the required performance level
12. False. Each type of oil with its additives
is right for the operating conditions it is
designed for.
13. .. viscosity . .. thicker
14 "S" Gasoline engines.
'C" Diesel engines
15 Moderate duty diesel and gasoline ser-
vice.
16. Tree.
17. It refers to laboratory analysis of used oil
to determine the types and amounts of
worr. metals In the oil.
18. (c) 125 to 250 hours.
19. The condition of the internal parts that
the oil lubricates.
20 So that contaminants will mix with the oil
and be drained out with it.
21 When it becomes contaminated with
either fuel. coolant. or metal chips.

97
 ENGINES 7:87

ANSWERS AIR INDUCTION 16 False

SYSTEM
17. The same oil as is used in the engine.
1 1 Naturally aspirated. and naturally
aspirated and scavenge blown. 18 (c) Lint and other contaminants appear
on the underside of the element.
2 Turbo charged
3 Turbo charged and after cooled
2 A naturally aspirated engine uses no aids
to get ail into and out of the engine. The
scavenge blown engine has an engine
driven air pump that forces fresh air into
the cylinders and drives the exhaust
gases out.
3 (c) exhaust driven turbine
4 By compressing the air.
5 When operating under full load.
8 (b) cool the inlet air belore it enters the
engine
7 Dry element cleaners. pre-cleaners. oil
bath cleaners
8 False
9 The vanes create a twist or cyclonic
movement in the air which throws the
dust and dirt particles outward and down
into a removeable dust cup. The air then
passes through the air filter to be furl; er
cleaned
10 It reverses direction causing most of the
dirt to become trapped by the oil and set-
tle out in the sump
11 (c) A red band is visible on the in-
dicator
12 Oil from an overfilled cup can be drawn
into the engine causing it to run away
13 1 Use caution when working around a
runr.ng engine with an open intake
bec 'use rags. loose clothing. etc.
car be drawn into the intake.
2 Never leave an open intake on a
stopped engine Cover it with
something hard such as plywood.
14 When the restriction indicator indicates
the need, or at the intervals recom-
mended by manufacturers. More often in
severely dusty conditions.
15 The steam will only force the dirt to the
center of the element

98
7:66 ENGINES

ANSWERS EXHAUST SYSTEM

1. (c) muffle engine noise.
2. (d) a. b and c are all correct.
3. (a) 6 to 8.
4. Sharp bends cause too much restriction.
5 Carbon monoxide can find its way into
the cab.
6. Ensure that there is adequate ventilation
for the deadly exhaust gas, carbon
monoxide.
7. By running your hand a few inches above
the pipe.

99
 ENGINES 7:89

ANSWERS - FUEL AND FUEL SYSTEMS 23. It does not vaporize readily and could
cause hard starting.
1. fuel tank
fuel pump 24. Cetane number measures the ignitability
of the fuel; the higher the cetane number
carburetor the shorter the period.
2. (d) all of the above. 25 1. protection of fuel quality.
3. difference in pressure. 2. safety
4. ($1) give a richer mixture for cold starts. 26. A light-colored tank reflects sunlight.
Thus the tank is cooler and not as much
5. .. . propane. butane. fuel evaporates.
6. (c) stored under pressure 27. ... gum one month three
7. vaporizes before it reaches the car- months.
bu;etor. whereas gasoline is vaporized in 28. Paint the tank a light color. and shade
the carburetor. the tank.
8. .. . converter .. 29. (d) 24 hours.
9. It burns cleaner than the other two fuels: 30. (c) fill the tank at end of each shift or
its exhaust contains less carbon day.
monoxide.
31. False.
10. A diesel engine injects fuel directly into
each cylinder. A gasoline engine delivers 32. LPG is stored in a pressurized tank and
a mixture of fuel and air to the com- therefore has no loss due to evaporation
bustion chambers. and no deterioration with time.
11. (c) both (a) and (1)1 are right 33. three to four inches so that the dirt and
water that have settled don't get drawn
12. LPG tanks must be heavier and stronger up witn the fuel.
because the fuel is stored under
pressure. 34. 1. fuel lines for leaks and damage.
13. (c) Microns. 2. water accumulation in water trap or
primary filter.
14. (d) fuel pump and carburetor. 3. momentarily open the tank drain to
15. shuts off the fuel when the system is not check for contaminants.
operating. 4. clean the tank breather.
16 1 the fuel tends to be impure. 35. (d) fill the new filter with fuel before in-
2. injection parts are precision made stalling it.
and dirty fuel will damage them. 36. air ...
17. (b) camshaft.
37. (c) fuel strainer frosts up.
18. False.
19. ... overtighten ...
20. Each fuel has its limits as to how much it
can be compressed and still burn
properly.
21. (b) diesel.

22. Octane is a measure of anti-knock

properties. The higher the octane rating
the less tendency the fuel has to knock.
7:90 ENGINES

TASKS ENGINES PREVENTIVE MAINTENANCE SERVICE ON

LUBRICATION SYSTEMS
PREVENTIVE MAINTENANCE SERVICE ON
COCLING SYSTEMS DAILY AND ROUTINE MAINTENANCE
CHECKS
DAILY AND ROUTINE MAINTENANCE
CHECK 1. Check the oil for water or fuel con-
tamination Report if contamination is
1. Check any liquid cooling system for leaks. found.
for the condition of hoses. the tension of
belt(s). the condition and operation of tl'e 2 Check the oil level. and if low. top it up
shutters and fan. for dirt accumulation and with the correct type of oil.
possible air flow restriction of radiator. 3 Check the lubrication system for leaks. for
and for the level and condition of coolant the condition of lines or hoses. and check
Perform any minor repairs such as ad- the operation of breathers and vents. Do
justing. tightening. cleaning. or report any any minor repairs. or report suspected
suspected unsafe operating conditions to unsafe operating conditions
a journeyperson.
SCHEDULED MAINTENANCE
SCHEDULED MAINTENANCE
Using the correct tools and procedures stated
1. Using the correct tools and procedures in the service manual:
stated in the service manual.
1. Drain the oil sump and filters.
(a) Drain the coolant.
Reverse-flush the radiator and 2 Remove and clean the filler housings. and
(b)
engine block. correctly install new filters. being careful
to keep filters and gaskets clean.
(c) Remove, test. install thermostat.
(d) Install new filter element (if equip- 3 Insert and tighten drain plugs. and fill the
sump with the correct types and amount of
ped).
oil.
(e) Fill the system with water/anti-freeze
solution and run the engine until the 4 Start and run the engine and check the
system is up to operating tem- complete system to ensure there are no
perature. Check the coolant level. leaks
and top up if low. Check the cooling 5 Stop the engine. wait for five minutes and
system to ensure it has no leaks. recheck the oil level. adding oil If
2. Using an anti-freeze hydrometer. test the required.
coolant to make certain there is sufficient
range against freezing of coolant for your SERVICE REPAIR ON LUBRICATION
region. SYSTEMS
When oil contamination is found in a machine
Or an internal component has failed. perform
flushing procedures
1. Drain the complete system.
2 Remove, flush and re-install the oil cooler
and connecting lines. and clean the filter
housings.
3 Install the flushing oil, run the engine.
stop and drain the system
4 Repeat normal filler installation. oil fill-up
and running and checking procedures.

101
 ENGINES 7:91

PREVENTIVE MAINTENANCE ON SERVICE REPAIR

AIR INDUCTION SYSTEM
1. Get experience installing exhaust sy- I
DAILY AND ROUTINE MAINTENANCE components such as mufflers. piping and
CHECKS mounts. When installation is complete run
the engine and check to ensure there are
t. Practice safely when working around no leaks.
open air inlets on a running engine
rags. loose clothing. etc.. can be sucked FUEL SYSTEM
into the manifold
SAFETY
Practice cleanliness when working on air
induction systems all pipes. ducting. 1. Practice safety with regard to fuel com-
lifter housings must be absolutely clean bustibility. Practice absolute cleanliness
on assembly when working with fuel and fuel systems.
2. Run the engine and check the air cleaner ROUTINE MAINTENANCE CHECK
restriction indicator (if equipped). Stop the
engine, carefully inspect all air induction 1. Visually inspect a complete fuel system
piping and replace any cracked or from the tank to the engine (to include
damaged sections, remembering to shut-off valve. lines or hoses. filters, trans-
lighten all clamps. fer pump and return line) for leaks or
damagq. Do any minor repairs and/or
3 Inspect the turbo charger and/or blower report unsafe operating conditions.
for evidence of nil leaks. and if any are
found make minor repairs, With the SCHEDULED MAINTENANCE
engine running check the turbo charger
and/or blower for excessive noise. Report 1. On a vehicle equipped with a diesel
if a problem is suspected. engine:

SCHEDULED MAINTENANCE (a) Open the drain on the fuel supply

tank sufficiently to remove any ac-
Consulting the service manual. do preventive cumulation of water and dirt.
maintenance service on pre-cleaner and air
cleaner(s): (b) Check the water trap and drain if
required.
t. Oil bath type thoroughly wash the oil
cup and the element and change the oil, (c) Install new fuel filter(s).
2. Dry type disassemble the cleaner. (d) Bleed the system to remove air.
clean the container housing. clean or (d) Start the engine and check to ensure
replace the filter element and reassemble. there are no leaks.
EXHAUST SYSTEMS

SAFETY
t. Practice safely when removing and in-
stalling exhaust parts. If the engine has
lust been running the parts will be hot.
Exhaust parts. especially on large
machines, can by heavy.

ROUTINE MAINTENANCE CHECK

1 Completely inspect an exhaust system for
leaks and for loose components and make
any necessary minor repairs.

102
 BASIC ELECTRICITY 8:1

FUNCTIONS OF ELECTRICITY ELECTRON THEORY

IN HEAVY DUTY VEHICLES
This block begins with a discussion of the
Electricity performs many important functions Electron Theory. the most widely accepted ex-
in the Heavy Duty Vehicle and Equipment planation of electricity.
field. Electricity is used to:
Before you can understand what electricity is.
1 Supply power to turn the eagine over for you first have to have a bases picture of en
starting. atom. All elements are made of billions of
atoms. Atoms have particles called electrons
2. Provide the spark ignition for each cylin- in orbit around a core of protons; the number
der in a gasoline engine. of electrons is the same as the number of
3. Provide power for all the lights on a protons. Electrons have a negative (-)
vehicle: charge. while protons have a positive (+)
charge. The siinplest atom is hydrogen having
head lights a single electron in orbit around a single
tail lights proton. Uranium is one of the most complex
stop lights elements with 92 electrons and 92 protons.
signal lights Models of the two atoms are shown in Figure
dash warning lights 8-1.
cab light Kuonoll
0446,,
.e
4. Operate the horn.
PROTON
5. Supply power for electrical gauges such
as:

fuel level gauge Pli

0 0
ELECTRON
7

oil pressure gauge

temperature gauge 4NAre:04.t'''`
(8-1)
6. Power electrical accessories such as. HYDROGEN ATOM URANIUM ATOM
Counesy N John Deere Ltd
radio
heater In their natural state atoms have an equal
air conditioner number of positive protons alid negative elec-
wipers trons. The atoms are therefore electrically
neutral. This neutral state, however can be
7 Power many varieties of magnetically altered. If an electron is attracted away from
operated controls such as: an atom. the atom will have a positive charge
starter switches since it will have one more proton than elec-
transmission shift controls tron. Or vice versa, if an electron is added to
hydraulic valves an atom, the atom will have a negative charge
because it has one extra electron.
8. Supply power to maintain the battery
charge level. The element copper is widely used in elec-
trical systems because it is a good conductor
of electricity. The reason for copper's good
conductivity can be explained by looking at a
diagram of its atom (Figure 8-2)

0 :111
k

is A.1
(8-2) r
STRUCTURE OF - Courtesy 01
.
A COPPER ATOM John Deere Ltd
COPPER ATOM

104
8:2 BASIC ELECTRICITY

The copper atom contains 29 electrons the definition of electricity. Electricity IS the
distributed in four separate shells or rings. flow of electrons from atom to atom in a con-
Notice that the outer ring has only one elec- ductor in the direction of negative to positive.
tron; it is this one electron that makes copper
a good conductor of electricity. Because Of course. the above description of electron
there is only one electron in its outer orbit flow is simplified On an actual cross section
where many could theoretically fit, and be- r T a copper wire there are billions of copper
cause this electron is quit t a distance from atoms and so billions of electrons will be
the positively charged nucleus that attracts or passing amongst them. These electrons will
binds the clectrons to the atom, the copper continue to flow as long as the positive and
atom does not hold onto the electron too negative charges are maintained at each end
strongly. Therefore. copper atoms have the of the wire By adding new electrons to the
tendency to both give up or accept an elec- negative end of the wire and by taking elec-
tron in its outer orbit. trons away from the positive end of the wire as
they get there (this is what a battery does) the
Consider what happens in a copper wire electrons or electric current will flow in-
where there are a string of copper atoms with definitely.
a positively charged atom at one end (i.e., the
atom has no electron in its outer ring) and an A basic idea of electricity is by no means easy
atom with negative charges at the other end to grasp Electricity is spoken of as flowing in
(i.e.. the atom has an extra electron, that is a wire. just as water is said to flow in a hose.
two electrons in its outer ring). Since positive But water is a real substance that you can see
charges attract negative charges, the and touch Elect icity on the other hand, is not
positively charged first atom will attract the a substance You cannot point to a material
negatively charged electron in the outer orbit and say that is electricity Rather, electricity is
of the second atom. a force of attraction that causes conductor
electrons to move and thus to have energy.
This electron will jump over to the positively Having no substance itself, the force of elec-
charged atom giving the atom the electron it tricity uses the substance of the conductor to
was missing in its outer ring (Figure 8-3). carry its energy. Like the wind, electricity can
be felt. the results of its energy can be seen,
but electricity. itself, can't be looked at and
examined.

BASIC FACTORS OF ELECTRICITY

There are three basic factors of electricity:
current
voltage
The first atom has achieved a neutral state. resistance
out now the second atom is left with no elec-
tron in its outer ring, and so it has a positive Current
charge Its positive charge attracts the The flow of electrons through a conductor is
negatively charged electron from the third called an electric current and is measured in
atom. The third atom will attract an electron amperes. One ampere is a current of 6.28
from the fourth, the fourth from the fifth, and billion billion electrons passing a given point
so on The second to last atom will take an in the conductor in one second. The current
electron from the last atom which being or amperage of a circuit, then, is a measure of
negatively charged has two electrons in its how many electrons are flowing in the circuit.
outer orbit. Now all the atoms along the row
have the right number of electrons in the Voltage
outer ring. In the process electrons have
passed from atom to atom. drawn to the One end of a current carrying conductor has
positive end aicng the line of atoms from the a positive charge, and the other end a
negative end. Looked at in terms of the negative charge. The strength of the charge
direction that the electrons move, a flow of depends on how many extra electrons there
electrons has taken place from the negative are at the negative end or conversely how
end to the positive end. This last statement is many electrons are missing at the positive

105
 BASIC ELECTRICITY 8:3

end. The greater the number of extra elec- Resistance

trons (or missing electrons) the greater the
charge or the difference between the two All conductors offer some resistance to the
ends. Voltage is the term used :43 measure the flow of current. Resistance is caused by:
strength or force of the attraction between the 1. Each atom resisting the removal of an
positive and negative charges. Of course, the electron due to its attraction toward the
stronger the charges at eitner end the greater core.
will be their force of attraction for one
another, or their voltage. 2. Collisions of countless electrons and
atoms as the electrons move through the
Voltage is the force that causes a flow of conductor. The amount of resistance
current in a conductor. Voltage can be depends on the material of the conductor,
generated by a storage battery or by a its thickness or diameter, and its length.
generator. Note that voltage is a potential
force and can exist even when there is no In a circuit the resistors are the electrical ac-
current flow. For example, a storage battery cessories, the lights, the electrical motors, the
can have a potential of 12 volts between its gauges, etc.
positive and negative terminals, and this
potertial exists even though no conductors The basic unit of resistance is the ohm. One
are connected to the posts. Voltage, also ohm is the resistance that will allow one am-
called potential differences is stored in a bat-
pere to flow when the potential is one volt.
tery in the form of a surplus of electrons at the
The symbol for ohms is -n- .
negative post and a corresponding lack of
electrons at the positive post. When a con-
ductor is attached to the posts the surplus
electrons at the negative post will travel to the
positive post. As the electrons arrive, the
positive post transfers them back through the
battery to the negative post, maintaining the
difference between the posts.

ELECTRIC CIRCUIT VERSUS A HYDRAULIC CIRCUIT

The chart below compares an electrical circuit with a hydraulic circuit.

Element Hydraulic Electric

Compared Circuit Circuit
fluid flows in hydraulic electrons flow in copper
circuit lines to operate hydraulic wires to operate electric
cylinders accessories

source of energy pump battery, generator

flow rate gallOnS per minute amperes (electrons per

second) (I)

working energy pressure voltage (E)

resistance friction loss ohm (R)

106
1J -
8:4 BASIC ELECTRICITY

BASIC ELECTRICAL CIRCUIT

A basic electrical circuit has three parts
(Figure 8-4):
voltage source such as a battery
resistor such as a light bulb
a conductor such as copper wire to
connect the circuit
CONDUCTOR

BATTERY
RESISTOR (8-6)
Look at the triangle, as you read these for-
-T mulas E = IA, I
triangle works. Ft
R=
1
to see how the
(8-4)
Courtesy of John Deere Ltd Sample Problems
An ammeter measures the current in an elec- 1 A circuit has 12 volts and a resistance of
trical circuit, a voltmeter the volts. and an three ohms What is its amperage?
ohmmeter the ohms (Figure 8-5).
Solution:
You know the volts and the ohms so use
AMMETER the formula for the amps:
RESISTOR volts
BATTERY = or amps
I =
ohms
VOLTMETER
1 2
(8-5) Courtesy of John Deere Ltd I = four amps.
3

Knowing the basic information about an elec- 2 Whal voltage is needed to send a five amp
trical circuit means knowing the volts. amps current through a 8 7 ohm resistor?
and ohms in the circuit. An electric& formula Solution:
called Ohm's Law relates these three quan-
tities: You know the amps and the ohm so use
the formula for the volts'
E (volts) = I (amps) x R (resistance)
E= IR or volts = amps x resistance
Because there are three quantities. there are
three formulas' E= 5 x 8.7
E In 43.5 volts
E = IR I = R
R
ELECTRICAL TERM DEFINITIONS
If you know any two of the quantities you can Conductor Any substance that is a good
find the third by applying the above formulas.
transmitter of electricity All metals and many
For example. if you know the amps (I) and the
liquids are considered conductors. In general
ohms (A). multiplying the amps times the
any substance composed of atoms with less
ohms will give the volts (E). Or if you know the than four electrons in its outer orbit is a con-
ohms (R) and the volts (E), dividing the volts ductor.
by the ohms will give the amps. An easy way
to remember these formulas is by using the Insulator Opposite to a conductor. Any
triangle in Figure 8-6 (A similar triangle was substance that is a poor transmitter of elec-
used in Hydraulics with pressure. force and tncity. Insulators usually have more than four
area.)

107
 BASIC ELECTRICITY 8:5

electrons in their outer ring. Glass, plastic.

mica, bakelite and rubber are examples of in-
sulators.
Closed Circuit A closed circuit has (Figure
8-7):
1. a circuit path with no breaks in it.
2. a resistor to control the amount of current (8-9)
flow.

CONDUCTOR CREATING A
SHORT CIRCUIT

In a short circuit there is little resistance since

the current is not travelling through the
resistor (the light). Looking at the formula
amps = volts , if the ohms. the quantity you
ohms
are dividing by. is very small because of the
(8-7) short circuit, it means that the amps will be
Open Circuit
large. So large. in fact, that the conductor
in an open circuit the circuit would be burned up and destroyed.
path is opened either by a switch or by a
broken wire. In Figure 8-8 the current can't
reach the light because its path is broken. All DIRECT CURRENT AND
light circuits in homes are open circuits when ALTERNATING CURRENT
the switch is in the off position.
Direct current (DC) travels in one direction
only whereas alternating current (AC) con-
stantly reverses direction. Batteries produce
DC and therefore all the electrical ac-
cessories used on heavy duty vehicles
operate on DC.

WATTS
Watts measure electrical power; watts are
found by multiplying volts x amps. In a simple
closed circuit having 12 volts and 2 amps. the
number of watts is 12 x 2 = 24. The circuit is
consuming 24 watts of electrical power. The
amount of electrical power is usually stated in
kilowatts (kw): 1000 watts = 1 kilowatt.
(8-8)

Short Circuit A short circuit occurs in a cir-

cuit when the current can take a shorter
course, bypassing the route it was supposed
to take. In Figure 8-9 the lamp won't light be-
cause the current is short-circuited.

108
8:6 BASIC ELECTRICITY

BASIC ELECTRICAL SYMBOLS

+ POSITIVE --0- CONNECTION

-'"' NEGATIVE

F--- BATTERY ( CONDUCTOR

CROSSOVER

-4AAr-- RESISTANCE OR LOAD

DC GENERATOR

_L..
-
..
GROUND

DC MOTOR

o
Cr-
!GI; TION COIL

DISTRIBUTOR CONTACTS
OR AC GENERATOR

--95:634\- INDUCTOR (SOLENOID)

CI
---11100.41-SWITCH (OPEN)

--I CONDENSER OR CAPACITOR

LIGHT BULB
(6)

--> '.."--SPARK GAP -011----DIODE (ONE-WAY)

(8.10)

109
 BASIC ELECTRICITY 8:7

TYPES OF ELECTRICAL CIRCUITS

There are three types of circuits (Figure 8-11) (8-11) Courtesy of John Deere Ltd

I I +I
SERIES PARALLEL SERIES PARALLEL
SERIES several resistors PARALLEL: more than one SERIES PARALLEL: has
connected so that current path for the current to flow. some resistors connected in
can take only one path Resistors are side by side series and some connected
and provide separate routes in parallel.
for the current.
Series Circuits
A basic series circuit may have a three-ohm In a series circuit. the total circuit resistance
(3 .a) resistor connected to a 12-volt battery is equal to the sum of all the resistors. In this
(Figure 8-12). circuit, the total circuit resistance is 4 J 2 = 6
4 AMPS ohms. The current from Ohm's Law is:
E 12 ...
1 1= = = c amperes.
12
-1 3S1
R 6
Voltage across the two-ohm resistor can be
+T figured using Ohm's Law: E -= IR = 2 x 2 = 4
(8-12) volts. For the four-ohm resistor, E = 2 x 4 =8
Courtesy of John Deere Ltd volts. These values are called the voltage
drops. and the sum of all voltage drops in the
To find the current. use Ohm's Law, where circuit must equal the source voltage. or 4 + 8
= 12 volts. An ammeter connected in the cir-
E 12 cuit will read two amps, and a voltmeter con-
I= 4 amperes. or 4 amps.
R 3
nected across each resistor will read four
volts and eight volts.
The series circuit in Figure 8-13 has a two In summary. series circuits have the following
chm resistor and a lour ohm resistor con- features:
nected to a 12 volt battery.
1. The current through each resistor is the
same. Ohm's Law states that if a circuit
has a given amount of volts and ohms.
then a set quantity of amps will be drawn
through the circuit. Since the amps travel
only one path, they are the same
throughout the circuit. Think of this
(8-13) current travel in terms of the electron
8 VOLTS theory. A set number of electrons set out
COurt03Y of John Deere Ltd from the negative terminal to travel to the

I0
8:8 BASIC ELECTRICITY

positive terminal. Since they can take only Electrons set out from the negative ter-
one route. the number of electrons minal. Some of them take the 31L route to
traveling (i e . the number of amps) will be the positive terminal, and some the 612
the same at any point in the circuit route. (Note the electrons will take the
path of least resistance so that twice as
2 The voltage drops in a series circuit. many will lake the 3 -11 route as will take
Unlike current. voltage is not the same the 61L route.) Since the number of elec-
throughout the circuit When an electron trons is split up among the two circuits,
sets out from the negative terminal it has a the amps will vary at different locations of
certain strength of charge or attraction the parallel circuit. The sum of the amps
(i e.. volts) for the positive terminal. But from all the circuits will equal the total
there are resistors in its path. These amts of the circuit.
resistors weaken the electrons force of at-
traction because part of their force or The current through each resistor or
strength is needed to get through the branch of the circuit can be figured using
resistor. Thus as the electron Ohm's Law. For the six-ohm resistor,
progressively travels through resistors A
=
=E ,
= 12z amps.
more and more of its strength or attraction
A 6
for the positive terminal is used up. Over a
series of resistors. so many volts will be 12
used to get the electrons through the first For the three-ohm resistor. 1 = =4
resistor. so many through the second and 3
so on. the amount of volts used up at each amps. The total current supplied by the
resistor depending on how large the battery is 2 + 4 = 6 amps (Figure 8 -15),
resistance is. After pushing their way
through the last resistor they have little 6 AMPS,
strength or voltage left. This progressive
consumption of voltage to get through
resistors is called voltage drop. Since the
voltage drops after each resistor, voltage
varies throughout the circuit Note that the
sum of the drops equals the total voltage 4-6 AMPS
at source. (8-15)
CourtesY of John Deere Ltd.
Parallel Circuits
1. In a series 4, suit the electrons (or amps) The total resistance of the parallel circuit
have one path to follow and thus the am- is equal to the voltage divided by the
12
perage is the same throughout the circuit total current or -- = 2.n..
Not so in a parallel circuit. In a parallel 6
circuit the amps have two or more paths to 2. In a series circuit voltage drops after each
follow The parallel circuit in Figure 8.14 resistor and therefore full voltage is not
has two paths for electrons to take present at each resistor. The opposite is
true in a parallel circuit: full voltage is
available at each resistor. Why is . full
voltage present in parallel circuits?
Examine the parallel circuit in Figure 8-16.

t 6.rL 3

+
(8-14)

(8-16)

111
 BASIC ELECTRICITY 8:9

An electron starts out from the negative Series Parallel Circuits

terminal with a 12 volt charge or attraction
for the positive terminal As seen above, Series parallel circuits are not commonly
some of the electrons will take the route found on vehicles: therefore. they won't be
through the 6stresistor to get to the discussed here.
positive terminal and some electrons will
take the route through the 3 ohm resistor. COMPARISON OF SERIES AND
The electron reaching the 6 Aresistor has PARALLEL CIRCUITS
a 12 volt attraction because it hasn't gone Both the series and parallel circuits in Figure
through any other resistors to drop not 8-17 have three 4 ohm circuits.
will it have to go Through any other ones.
The same can bb said of the electron
reaching the 3 IL resistor. This electron
_AM/
4n.
too has a 12 volt attraction because it
hasn't gone through nor will it have to go
through any other resistors.
In summary. parallel circuits have the
following features:
4a
(a) The voltage across each resistor is
the same.
(b) The sum of the separate currents
equals the total current in the circuit.
(c) The current through each resistor will
be different if the resistance values
are different. +I L +
12V (8-17) 12V

X 1348 SERIES PARALLEL

Series Circuit Courtesy of John Deere tad

Resistance: 4 + 4 4. 4 = 12 ohms
volts 12
Amperage: amps = = _ = 1 amp
ohms 12

Power: volts x amps = 12 x 1 = 12 watts

. resistance = 12 ohms: amperage = 1 amp power = 12 watts

Parallel Circuit
v 12
Amperage: circuit 1 amps = _
volts = _ = 3 amps
circuit 2 ohms 4 3 amps
circuit 3 3 amps
TOTAL 9 amps
Resistance: equivalent resistance is:
volts 12
ohms = = = 1.3 ohms
amps 9

Power = volts x amps = 12 x 9 = 108 watts

Fresistartm = 1.3 ohms: amperage = 9 amps power = 108 watts I

112
8:10 BASIC ELECTRICITY

In Summary:
Series circuit high resistance. low amperage. low power (wattage)
Parallel circuit low resistance. high amperage. high power
Most circuits in vehicles are parallel circuits.

MAGNETISM S POLE N POLE

Electricity is closely related to magnetism. 7/ pit
The effects of magnetism were first observed
when naturally found fragments of iron ore
fr.'
called lodestone were seen to attract other / 00 --
e=r z
pieces of iron (Figure 8-18).
..
fto ... %.

;:::

/./
1.*
.100 h t 4. \
di
IRON IRON
FILINGS FILINGS
(8-18) MAGNETISM (8-19) MAGNETIC FIELD OF A BAR MAGNET
Courtesy of John Deere Ltd Courtesy of John Deere Lld
it was further discovered that a long piece of
The pattern shows that the lines of force are
lodestone iron, ore. when suspended in air, heavily concentrated at the N and S poles of
would align itself so that one end always the magnet. and then spread into the
pointed toward the North Pole of the earth surrounding air between the poles. The con-
(Figure 8-18). This end of the iron bar was centration or number of lines at each pole is
called the north pole, or N pole, and the other
equal, and the attractive force on the iron
end the south or S pole. Such a piece of iron
filings at each pole is equal. Notice that the
ore was called a bar magnet. The bar magnet force of attraction on bits of metal is greatest
is the basic part of the compass, a
where the concentration of magnetic lines is
navigational aid that has been used for over greatest For a bar magnet. this area is next to
1.000 years.
the two poles.
Magnetic Fields Taking two bar magnets and experimenting
with their polarities, you will find that unlike
Further study of the bar magnet revealed that poles. north and south, are attracted to one
an attractive force was exerted upon bits of another while like poles, north and north or
iron or iron filings even though the iron filings south and south. repel one another. The force
were some distance away from the bar of attraction gets stronger as the two unlike
magnet It was clear that a force existed in the poles are drawn closer together, and
space close to the bar magnet This space correspondingly, the force of repulsion gets
around the magnet to which iron filings are at- stronger as the two like poles are pushed
tracted is called the field of force or magnetic closer together. Stated briefly this basic law
held of magnetism is: unlike poles attract. like
poles repel (Figure 8-20).
The theory of magnetic lines of force can be
dramatized by sprinkling iron filings on a
piece of paper resting on top of a bar magnet. UNLIKE
When the paper is lightly tapped. the iron POLES
filings line up to form a clear pattern around ATTRACT
the bar magnet (Figure 8-19). LIKE
POLES
REPEL

(8-20) MAGNETIC FORCES BETWEEN POLES

OF BAR MAGNETS
Courtesy of John Deere Ltd

113
 BASIC ELECTRICITY 8:11

Just as there are good end poor conductors of Summary of Magnetism

electricity, so there are good and poor
magnetic materials. Iron has good magnetic Every magnet has an N and S pole. and
properties whereas wood, paper, glass, cop- a field of force surrounding it.
per. zinc are less magnetic. Magnetic materials are acted upon
when located in a field of force.
How Magnets Are Made
Unlike poles attract and like poles
An ordinary iron bar can be converted into a repel.
magnet in a number of different ways. One
method is to stroke the iron with another An unmagnetized piece of iron can be-
piece of iron that has already been come a magnet through induction.
magnetized. The effect of inducing
magnetism into the iron bar is called
magnetic induction. Another method of ELECTROMAGNETISM
magnetic induction is simply to place an iron An experiment with a compass and a wire
bar in a strong magnetic field (Figure 8-21). carrying current reveals the connection be-
410,wdoulow of os awe ua 410 asm.KW4Ann41 *,,,,,,41._ tween electricity and magnetism. When a
vAllrmivegigftkaAretn.P\ compass is held over the wire, the needle
reowriv v "0.a.tisi to M.reeerOesernmhIPOlhlw,1,,...4:-.
IS, turns crosswise to the wire (Figure 8-23).
Since the only thing known that will attract a
.os.0". .. 1..... 4.0. w.011...r4 compass needle is magnetism, it is obvious
....../.4.r .1.0.441/14awanmo/...01.
."...0.11.....,NVOIY.0..4 $:.,...
that the.zurrent in the wire creates a magnetic
...7.Z.H "41,1COMSYNN db. A I MOtiniV 4117 cdnr.0_ field around the wire.
it ....t.

-44 """ .4.1.MWOWNS OgOWAIMI

.140r,o, To.hhot
0,1741;04.04
S
was. v. ow ("Aar

(8-21) MAGNETIC INDUCTION OF AN IRON BAR

Courtesy of John Deere Ltd

The lines of force in the field passing through

the iron bar will cause the bar to become a
magnet as long as it is located in the field. If CURRENT
the bar is withdrawn from the field of force, CARRYING
and if its composition is such that it retains (8-23) WIRE
some of its induced magnetism, it is then said ELECTRIC CURRENT CREATES ITS OWN
to be permanently magnetized and is called a MAGNETIC FIELD
permanent magnet. Most permanent magnets Courtesy of John Deere Ltd
are made of hard metals composed of alloys.
(Soft metals will not retain much of their The nature of the magnetic field around the
magnetism.) Some of the more common wire can be seen when a current-carrying wire
magnetic alloys are nickel-iron and is run through a piece of cardboard, and iron
aluminum-nickel-cobalt and magnets using filings are sprinkled on the cardboard. The
the alloys are trade-named ALNICO magnets. iron filings align themselves to show a clear
Permanent magnets ar9 found in many pattern of concentric circles around the wire
shapes, including the horseshoe magnet (Figure 8-24).
,=0
which concentrates the lines of force in a
small area between two poles (Figure 8-22).
r ....., S., \
Horseshoe magnets are widely used in volt- ( I'... .._ s% , ,, \
....
-,-% 's \ N ,.
i/r , r'"'- %

meters and ammeters. I

i Illtio' ,,, t t ;
1 t,, It\ rt,'1,Mt)tilt 1
,, \, --//1/
I
,
% s / .. / /I'
\: ,:,_\_:::::::::::-,C:1/"//1
113 DIRECTION OF
(8-22) FORMING A HORSESHOE MAGNET (8-24) CURRENT FLOW
Courtesy of John Deere Lid Courtesy of John Deere lid

114
8:12 BASIC ELECTRICITY

The circles are more concentrated near the When a number of conductors are placed
wire than farther away. Although the iron side by side, the magnetic effect is in-
filings on the cardboard show only the pattern creased as the lines from each conductor
in one plane., remember that the concentric join and surround all the conductors. The
circles extend the entire length of the current - ratio of increase can be seen in the
carrying wire. following:
When a current is travelling in one direction Two conductors lying alongside each
and a compass is placed in the elec- other carrying equal currents in the
tromagnetic field. the needle aligns itself so same direction create a magnetic
that magnetic lines enter its S pole and leave field equivalent to one conductor
its N pole. If the direction of the current is carrying twice the current.
changed the compass needle reverses its
position and points in the opposite direction. 2 If two adjacent parallel conductors are
Thus it can be concluded that: carrying current in opposite directions,
the direction of the field is clockwise
Electro-magnetic lines have direction, and around one conductor and coun-
they change that direction when the terclockwise around the other. When the
currert flow is reversed in the wire. two wires are placed close together. as in
Figure 8-26, you car see that there is a
Points About Electromagnetism concentrated field between them because
the fields from the two wires merge
1 The number of lines of force, or strength together. Since both lines of force are run-
of the magnetism. increases as the ning in the same direction there is a
current through the conductor is in- strong field between the conductors. A
creased. More current creates a stronger much weaker field exists to the outside of
field. If a compass is moved farther away the wires.
from the conductor. a point finally is
reached where the compass is unaffected
by the field. If the current is then in-
creased. the compass needle will be af-
fected and will again indicate the direc-
tion of the magnetic field (Figure 8-25).

STRONG FIELD BETWEEN

CONDUCTORS
CARRYING CURRENT IN
OPPOSITE DIRECTIONS
NEEDLE
UNAFFECTED (8-26)

ONE AMPERE
(8 -25)

CONDUCTORS TEND TO
MOVE APART
Courtesy of John Deere Lid

NEEDLE The strong held has an important effect on

ALIGNED the two conductors in as much as they
have 4 tendency to move away from one
another. Putting this observation into a
general statement current carrying wires
THREE AMPERES
will tend to move out of a strong field and
into a weak field.
Courtesy of John Deere Ltd

115
 BASIC ELECTRICITY 8:13

3. When two adjacent parallel conductors

are carrying current in the same direction
a magnetic field. clockwise in direction,
will be formed around each conductor,
with the result that the magnetic lines be-
tween the conductors oppose each other
in direction. Thus the magnetic field be-
tween the conductors is cancelled out.
leaving essentially no field in this area
(Figure 8-27). The two conductors will
then tend to move toward each other. that
DIRECTION OF
is, from a strong field into a weak one. (8-28)
CURRENT FLOW

i
....'.., 41I Courtesy of John Deere Lid.

All the lines of force enter the inside of the

C");;r"flet)
\\*....,
loop of wire on one side and leave it on
the outside Given the angles of the forces
N.....1t...."4.P .``*--...." and the fact that the inside diameter of the
conductor is smaller than the outside
MAGNETIC FIELD diameter. the lines of force are more con-
BETWEEN CONDUCTORS centrated on the inside of the loop than on
CANCELS OUT the outside. A single loop of wire carrying
(8-27) current is called a basic electromagnet.
Electromagnets
Rather than one loop. an electromagnet has a
number of current carrying loops combined
together to make a coil as illustrated in Figure
8-29.
CONDUCTORS TEND
TO MOVE TOGETHER
Courtesy of John Deere Ltd

In points 2 and 3 above. the magnetic

fields were from two current carrying con-
ductors. The same principle could be
deduced using a conductor and a (8-29)
magnetic field from a magnet: the con- CONDUCTOR IN SEVERAL LOOPS MULTIPLIES
ductor would be pushed away from the THE MAGNETIC FIELD
magnetic field when the conductor's field Courtesy of John Deere Ltd
and the magnet's field ran In the same
direction; and conversely the conductor
would be pulled towards the magnet's
field when the two fields run in opposite
directions. This push and pull reaction be-
tween a conductor and a magnet's field is
the basic principle of an electric motor as
will be seen in the discussion of a starting
motor.
4. A straight current-carrying wire when
formed into a single loop still has a
magnetic field surrounding it. The lines of
magnetic force, however. have a different
pattern (Figure 8-28).

116
8:14 BASIC ELECTRICITY

The strength of the resulting magnetic held is 1000 ampere turns. The attraction on
the sum of all the single loop magnetic fields magnetic materials located in the magnetic
added together With lines of force leaving the field of each of these electromagnets will be
coil at one end and entering at the other. a the same.
north and south pole are formed at the coil
ends, the same as in a bar magnet. If the Summary Of Electromagnetism
current direction through the coil is reversed. -lectricity and magnetism are related
the polarity of the coil ends will also reverse because a magnetic field surrounds a
The above core could be called an elec- conductor that is carrying current.
tromagnet Useable electromagnetics.
however, have another -11a, ,t a . .on -- An electromagnet has a N pole at one
around which the iC 3C wrappt end of the iron core and an S pole at
(Figure 8-30) the other end. much like a bar magnet.
Every magnetic field has a complete
circuit that is occupied by its lines of
force.
((( /A 'IA` 'a 7I An electromagnetic field gets stronger
as more current flows through its coils
ELECTROMAGNETIC INDUCTION
From the point of view of electricity.
something eery important happens when a
conductor is moved across a magnetic field: a
(8-30)
voltage is induced in the conductor. This
IRON CORE INCREASES FIELD STRENGTH voltage is called electromagnetic induction.
Courtesy of John Deere Ltd Electromagnetic induction (i.e.. induced
The strength of the magnetic field at the N and voltage) can be observed by doing the
S poles is increased greatly by adding the following connect a sensitive voltmeter to the
iron core. The reason for this increase is that ends of a straight wire conductor Move the
while air is a very poor conductor of magnetic wire conductor across the magnetic field of a
Imes, iron is a very good one. The use of iron horseshoe magnet As the wire moves across
in a magnetic path may increase the magnetic the field the voltmeter will register a small
strength 2500 times over that of air. voltage (Figure 8-32).
CONDUCTOR
The strength of the magnetic poles in an elec- MOVEMENT
tromagnet is directly proportional to both the
r.umber of turns of wire and tne amount of
current flowing in the coil (Figure 8-31).
1 AMP 10 AMPS
11111.Plie VOLTMETER
4 READS VOLTAGE

MOVING CONDUCTOR ACROSS MAGNETIC

MIN FIELD VOLTAGE IS INDUCED

CONDUCTOR (8-32)
MOVEMENT
1000 100
PANS TURNS
r""

1000 AMPERE TURNS

(8-31)
Courtesy or John Deere Ltd VOLTMETER
READS NO
An electromagnet having one ampere flowing VOLTAGE
through 1000 turns, and another elec-
tromagnet having 10 amperes flowing through MOVING CONDUCTOR PARALLEL TO
t00 turns will each have a field strength of MAGNETIC FIELD NO VOLTAGE
IS INDUCED
Courtesy of John Deere Ltd

117
 BASIC ELECTRICITY 8:15

If the wire is moved parallel wtih the lines of Strength Of Induced Voltage
force. no voltage will be induced (Figure 8-32).
The conductor must cut across the lines of Three factors affect the strength of induced
force in order to induce a voltage. voltage:

Since a conductor cutting across the field has 1. The strength of the magnetic field.
voltage, it is a source of electric current. just If the magnetic field is made stronger. by
as a battery is. and must have a positive and a using a larger horseshoe magnet for
negative end. example, more lines of force will be cut by
the conductor in any given interval of time
In a battery the positive and negative ter- and the induced voltage will be higher.
minals are permanent. Electromagnetically in-
duced voltage, on the other hand. does not 2. The speed at which lines of force are cut-
have permanent polarity; the positive and ting across the conductor.
negative end can change depending on which If the relative motion between the con-
direction the wire is moved through the ductor and magnetic field is increased,
magnetic field. Figure 8-33 illustrates this more lines of force will be cut in any given
change in polarity and corresponding change interval of time and so the voltage will be
in current flow. higher.
3. The number of conductors that are cutting
across the lines of force.
In the example on the previous page one
conductor was passed through tne field
and a voltage was induced. If two wires
were moved across the field twice as
much current would be induced; if three
wires. three times as much. and so on.
Electrical motors, generators, coils. use
CURRENT FLOW
loops of wire rather then straight wire as
(8-33) DIRECTION
conductors. When a straight wire con-
ductor is wound into a coil and moved
across the field. all the loops of wire are in
series and the voltage induced in all the
loops will add together to give a higher
voltage.
Note that the strength of induced voltage is
related to the power needed to move the con-
ductors across the magnetic field, or vice
CURRENT FLOW versa. When current is induced in a con-
Courtesy or John Deere Ltd ductor, a magnetic field forms around the con-
ductor. So the magnetic field of the conductor
In the previous examples. if. instead of moving moves through the magnetic field of the
the wire across the field, the held is moved magnet Since an interaction occurs between
across the wires, the same voltage and the two fields, a resistance is set up against
current flow will be induced in the ware. the movement The more induced current, the
Therefore. it can be concluded that voltage stronger the resistance Therefore. as the
will be induced in a conductor cutting across amount of induced current increases and thus
a magnetic field when there is relative motion resistance increases. more power will be
between the two. Either the conductor can needed to move the conductors across the
move. or the magnetic field can move. field The practical application of this fact is
that the more current a generator or alternator
produces. the more power is needed to turn
them.

118
 r- .o.

8:16 BASIC ELECTRICITY

Summary Of Electromagnetic Induction Because the moving coil in the voltmeter is

very small and sensitive, the current through
Stronger magnetic field equals more the coil must be limited to safe values. To limit
induced voltage. current to a safe amount, voltmeters are con-
Faster relative motion equals more structed with a high resistor in series with the
voltage. coil. The voltmeter scale is calibrated ac- ,
cordingly to indicate the true voltage.
More conductors in motion equals
more voltage. Voltmeters are connected across (in parallel
with) the voltage to be measured. as shown in
More current induced equals more Figure 845.
power to move conductors through the
magnetic field. c
o
The basic electricity. magneticism. and elec- A
tromagnetism discussed above give the prin- 0
ciples that electrical components are built on.
Clearly understood. these principles will help
I (8-36)
you in diagnosing and repairing electrical CONNECT VOLTMETER IN PARALLEL
parts.
Courtesy 0 John Deere Lid
ELECTRICAL TEST EQUIPMENT Ammeters
To accurately test and diagnose electrical An ammeter measures the flow of electrical
problems, good test equipment is necessary. current in ampere*. Two types of ammeters
If values for voltage. current and resistance are used, a shunt ammeter and a tong am-
are not measured with suitable test meters. meter.
only a guess can be made as `') what defect
exists in the circuit. Shunt Ammeters

The following discussion will look at volt- Opposite to a voltmeter, the shunt ammeter
meters, ammeters. Pnd ohmmeters. What is has a low resistance shunt connected in
said about the three meters separately also parallel with the moving coil. The shunt sec-
applies to modern testers which often com- tion of the parallel circuit, therefore, conducts
bine two of the three meters in one test unit most of the current being measured leaving
(e.g., battery starter tester). only a small portion to flow through the coil.
Always connect an ammeter in series in a cir-
Voltmeter cuit: never connect it across .the voltage
source (Figure 8-36). If connected acrosS, or
A voltmeter (Figure 844) measures the in parallel. the meter could be damaged.
strength of electrical potential or voltage in a
circuit.
L
4 0
A
0
I
(8-36)
.
ALWAYS CONNECT AMMETER IN SERIES
Courtesy of John Deere Ltd.
Tong Ammeter
Tong ammeters measure the amps in a circuit
by measuring the Strength of the magnetic
field that surrounds the current carrying con-
(8-34) VOLTmETER ductor. The advantage of a tong ammeter is
Counesy of John Deere Ltd. that you can test without disconnecting any
wires. Current is measured by simply opening
the tongs and placing them over the wire.
However. a tong ammeter is not as accurate
as a shunt ammeter.

119
 BASIC ELECTRICITY 8:17

Ohmmeters CARE AND SAFE PRACTICES WITH

ELECTRICAL TESTING EQUIPMENT
An ohmmeter (Figure 8-37) measures the
resistance or ohms in a circuit The accuracy of electrical test equipment will
depend on how well it is looked after. Follow
these simple rules for care and use of the
equipment:
1. If in doubt of voltmeter, ammeter, ohm-
meter hook-up procedures. refer to in-
structions for the machine.
2. Do not overload the meter. Check the
meter setting before connecting the meter
into the circuit. For example, some volt-
meters can have four different setting
(8.37) OHMMETER ranges that fall between 4 and 40 volts,
Courtesy of John Deere Ltd One setting would be used when testing a
12 volt system, and a higher setting would
An ohmmeter has its own current supply, a dry be used on a 24 volt system.
cell battery, and should always be used on a
dead circuit. Never connect an ohmmeter to a 3 Remember the basic rule applied to each
live circuit as the external voltage may meter:
damage it. Keep the dry cell switched off Voltmeter connected in parallel
(a)
when the ohmmeter is not in use.
(b) Ammeter connected in series
Battery-Starter Tester (c) Ohmmeter connected to a dead
A battery starter tester (Figure 8-38) has a circuit only.
voltmeter and an ammeter combined into one 4. Avoid connecting the meter backwards as
unit. The tester will do a complete test on the reversing the connections is hard on the
battery and starting circuit. meter. Most meter connectors are color
coded, red for positive, black for negative.
5. Keep the instruments clean. Cover them
when not in use or store them in a clean
area.
6. Avoid testing in hot areas around an
engine as heat can burn or damage the
meter connectors.

(8.38) BATTERY-STARTER TESTER

(VOLT-AMPERE TESTER)
Courtesy 01 John Deere Ltd

120
8:18 BASIC ELECTRICITY

QUESTIONS ELECTRICITY THEORY 13. List the three types of electrical circuits.
1. Electricity flows in a conductor in the 14. Parallel circuits are most commonly used
direction of: in automotive and heavy duty vehicles.
Parallel circuits have:
(a) negative to neutral
(b) negative to positive (a) high resistance low amperage
(c) positive to negative (b) high resistance high amperage
(d) positive to neutral (c) low resistance high amperage
(d) nieCium resistance medium am-
2. Electricity is a form of: perage
(a) heat 15. The lines of force created around a bar
(b) light magnet is referred to as the
(c) energy The law of magnetism
states that
(d) magnetism
16. What does a bar magnet and a wire con-
3. True or False? The term current means ducting electricity have in common?
the flow of electrons through a con-
ductor. 17. An electromagnet is made by forming a
conductor into a coil and passing a
4. Briefly explain the term voltage. current of electricity through the coil.
5. All conductors offer some resistance to What is needed to complete this basic
the flow of current; the basic unit of electromagnet?
resistance is the: 18. A common term for expressing the
(a) diode strength of an electromagnet found by
multiplying the current flow times the
(b) thermistor number of turns in the coil is:
(c) ampere
(a) flux turns
(d) ohm
(b) current turns
6_ List the three basic parts of an electrical (c) magnetic turns
circuit.
(d) ampere turns
7. Match the unit of electricity with the
meter used to measure it. 19. What is the term used to describe
voltage produced by a conductor cutting
(a) Voltage (a) Ohmmeter across lines of force?
(b) Current (b) Voltmeter 20. True or False? Current is induced when
(c) Resistance (c) Ammeter a conductor moves across a magnetic
field but not when the field moves across
8. Use the formula for Ohm's Law to the conductor.
calculate the current flow in a circuit that
has 12 volts potential and a resistance of 21. Match the following test instruments with
four ohms. the correct method of connecting them
into a circuit:
9. Briefly describe a conductor.
(a) Ohmmeter (a) connected in
10. Briefly explain the difference between a series
closed circuit and a short circuit.
(b) Ammeter (b) connected in
11. Current flow can be direct or alternating. parallel
All accessories used on automotive and Voltmeter (c) connected to a
(c)
heavy duty vehicles operate on dead circuit
current generally
referred to as _______.
12. What does the term watt refer to and how
is it determined?

121
 BASIC ELECTRICITY 8:19

22. To avoid damaging test meters through

reverse polarity the test leads are color
coded for identification. The standard
combination is:
(a) red for negative, yellow for positive
(b) black for positive, green for
negative
(c) red for negative, black for positive
(d) red for positive. black for negative
22. What are the three factors that affect the
strength of the induced voltage created
by electrunagnetic induction?
24. Two adjacent conductors carrying
current in the same direction will tend to
one another.
25. Two adjacent conductors carrying
current in the opposite direction will tend
to one another.

122
 8:20 BASIC ELECTRICITY

LEAD ACID STORAGE BATTERIES Elements in different cells are connected in

series. The cells are separate from one
A battery stores energy for all the electrical another and so there is no flow of electrolyte
circuits in a vehicle the starting, charging. between them.
ignition, and accessory circuits. On demand
the battery produces a flow of direct current Batteries have negative and positive posts or
to operate the electrical components in these terminals. The positive post is larger to help
circuits. Battery current is produced by prevent the battery from being connected in
chemical reaction between the active reverse polarity. The positive terminal has a +
materials of the plates and the sulfuric acid in marked on i.s top, and the negative post a -.
the battery fluid or electrolyte Electrolyte Other possible identifying marks on or near
consists of 36% sulfuric acid and 64% water. the Posts are a "pos" and a "neg".
BATTERY CONSTRUCTION Conventional batteries have vent caps for
each cell: these caps cover access holes
A battery is made up of a number of individual through which the electrolyte level can be
cells in a hard rubber case. The basic units of checked and water added. The access holes
each cell are positive and negative plates also provide a vent for the escape of gases
(Figure 8.39). Negatively charged plates have formed when the battery is charging. The new
a lead surface, gray in color; the positive so called maintenance-free batteries have no
plates have a brown lead peroxide surface. vent caps. The electrolyte, for all practical
Both negative and positive plates are welded purposes, is sealed in. There is however one
together in separate groups. Plate groutos ar' small vent hole to allow any internal pressure
interconnected, as shown below. 1' r that to escaoe.
there is one more plate in the negative gi. up
than in the positive, allowing negative plates
to form the two outsides when the groups are
interconnected.
Each plate in the interlaced plate group is
kept apart from its neighbor by porous
separators which allow a free flow of elec- Courtesy of John Deere Ltd.
trolyte around the active plates. The complete
plate assembly is called an element.

TERMINAL
POST

PLATE STRAP
CASTING

NEGATIVE
PLATE
GROUP

SEPARATOR

ELEMENT

POSITIVE
PLATE
GROUP

(8 -39) CONSTRUCTION OF A STORAGE BATTERY

a
w

123
 BASIC ELECTRICITY 8:21

Each cell in a storage battery has a potential Discharging Cycle

of about two volts. Six-volt batteries contain
three cells connected in series, while 12-volt When a battery is supplying current. it is
batteries have six cells in series. For higher discharging. The chemical reactions in a
voltages, combinations of batteries are con- discharging battlry are as follows:
nected in series. in Figure 8-40 two 12-volt Positive I-lefts are made of lead peroxide
batteries are combined to give 24 volts (Pb02). The lead (Pb) rer-cts with the sulphate
radical (SO) in the electrolyte (H2SO4) to form
lead sulfate lPhSO4). Al the same time the
oxygen (0,) in the lead r enixide ,Jins with the
hydrogen (1-.! in the clec'rolyte to form water
(H20).
Negative Plates are made of lead. This lead
(8-40) also combines with the sulfate radicals in the
Courtesy of John Deere Ltd
electrolyte to form lead sulfate (PbSO4). These
Note that batteries of the same voltage can reactions are illustrated in Figure 8-41.
produce different amounts of current. The
reason for this is that the amount of current a loommiciOAD
battery can produce is dependent on the num-
ber and size of its plates. The more plates H,
there are the more chemical reactions can
take place between the electrolyte and the Pb b O1Hi SO,
plates and, therefore. a greater amount of
current is produced. Thus. if two 12-volt bat- DISCHARGING
teries have a different number of plates. the (8-41) Courtesy of John Deere Ltd
one with the greater number will supply more
current. In the discharging process. then, lead
sulphate forms on both the positive and
BATTERY ELECTROLYTE negative plates making the two plates similar.
These sulphate deposits account for the loss
The electrolyte in a fully charged battery is a of cell voltage because voltage depends on
concentrated solution of sulfuric acid in the positive and negative plates being dif-
water. It has a specific gravity of about 1.270 ferent. As the battery progressively
at 27'C, which means it weighs 1.270 times discharges more lead sulphate is formed at
more than water. The solution is about 36% the plates and more water is formed in the
sulfuric acid (112S0,) and 64% water (H20). electrolyte.

Battery Water Note that although the SO, radical leaves the
electrolyte, it never leaves the battery.
The purity of water for battery use has always Therefore, never add any additional sulfuric
been a controversial subject It is a fact that acid (1-12SO4) to a battery. The extra SO, would
water with impurities hurts the life and per- only cause the battery to self discharge at a
formance of a battery. The question is does higher than normal rate. Water is the only sub-
the impure water harm it in a significant Cara in a battery that has to be replaced.
amount? The controversy can be simply
resolved by saying that you don't have to use Charging Cycle
distilled water. but it is better for the battery if
you do. The chemical reactions that take place in the
battery cell during the charging cycle are
BATTERY OPERATING CYCLES essentially the reverse of those which occur
during the discharging cycle:
A battery has two operating cycles:
1. The sulphate radical leaves the plates and
discharging cycle goes back to the electrolyte replenishing
charging cycle the strength of sulphuric acid.

124
 8:22 BA SIC ELECTRICITY

2 Oxygen from the water in the discharged the battery is properly activated, many
electrolyte joins with the lead at the manufacturers furnish a packaged electrolyte
positive plate to form lead peroxide. The for their dry-charged batteries along with in-
chemical reactions during charging are structions for activation. These instructions
illustrated in Figure 8-42. must be carefully followed.

Wet-Charged Batteries
Wet-charged batteries contain fully-charged
elements and are filled with electrolyte at the
factory. A wet-charged battery will not main-
tain its state of charge during storage, and
must be recharged periodically. During
storage, even though a battery is not in use, a
(8-42) slow reaction takes place between the elec-
Courtesy of John Deere Ltd trolyte and the plates causing the battery to
lose its charge. This reaction is called self-
THE BATTERY AND THE discharge.
CHARGING CIRCUIT
The rate at which self-discharge occurs varies
Batteries operate in a charging circuit with a directly with the temperature of the elec-
generator or alternator. The battery supplies trolyte. A fully charged battery stored at a tem-
current to circuits and becomes discharged. perature of 38°C will be almost completely
The generator or alternator sends current to discharged after a storage period of 90 days.
the battery to recharge it. Operation of the The same battery stored at 15'C will be only
charging circuit varies with the engine speed. slightly discharged after 90 days.
When the engine is shut off. the battery alone
.. supplies current to the accessory circuits. At Wet-charged batteries. therefore. should be
low speeds. both the battery and generator stored in the coolest place possible which
may supply current. At higher speeds. the doesn't allow the electrolyte to freeze. Note
that a wet-battery which is kept fully charged
generator may take over and supply enough will not freeze unless the temperature goes
current to operate the accessories and also
recharge the battery. below 60 'C. where as a discharged battery
with a specific gravity of 1.100 will freeze at
TYPES OF BATTERIES
8 'C.
There are three types of batteries: Sulfated Wet-Charged Batteries
dry-charged Wet-charged c Aeries which are stored for
long periods of time without recharging may
wet-charged
be permanently damaged by the formation of
maintenance-free hard dense lead sulfate crystals on the plates.
To prevent these crystals from forming. wet-
Dry-Charged Batteries batteries in storage should be brought to full
charge every 30 days.
A dry-charged battery contains fully-charged
elements. but it contains no electrolyte. Once
Comparison Of Wet and Dry-Chargsd
activated with electrolyte it is essentially the
Batteries
same as a wet-charged battery. A dry-charged
battery retains its full state of charge as long In terms of storage. dry-charged batteries
as moisture is not allowed to enter the cells If have a big advantage over wet-charged bat-
stored in a cool. dry place. this type of battery teries because they require less maintenance.
will not lose part of its charge on the shelf For this reason most parts supply places. have
prior to being used. stocked the dry-charged batteries. It now ap-
pears. however. that maintenance-free bat-
Activating Dry-Charged Batteries teries with their sealed-in electrolytes are
going to replace the conventional batteries.
The activation of a dry-charged battery is
and so parts suppliers won't have a choice.
usually done at the warehouse where the bat- The maintenance-free batteries. will have to
tery is purchased or in the field by a dealer. To
be maintained in storage like the conventional
make sure the correct electrolyte is used and wet type.

125
 BASIC ELECTRICITY 8:23

TEST INDICATOR
(TERMINAL LOCATIONS ARE TERMINALS
SHOWN IN FIGURE 5) TEST
INDICATOR
FINGER GRIP
HANDLES
_.......0°"--

(8-43) Courtesy ci Delco Division of

General Motors Corporation

Maintenance-Free Batteries battery level doesn't have to be checked

and problems of over or undlrfilling the
In an effort to reduce battery maintenance, cells are eliminated.
and to make batteries more dependable and
last longer, the "maintenance-free battery 2. Gases are produced during the discharge
has been developed. Indications are that and charging process The gases rise to
these new batteries will mrke the con- the top of the case, are trapped by the
ventional battery obsolete. A maintenance- liquid gas separator. cool and condense.
free battery is similar in shape to a con- then drain back to the electrolyte reser-
ventional battery but it has no filler caps. The voir. Internal pressure that may occur is
electrolyte is completely sealed in. Note the released through a small vent hole. the
terminals on the two maintenance-tree bat- flame arrestor vent, in the side of the
teries in Figure 8-43: one has stainless steel cover.
threaded terminals and the other has sealed
terminals located on the side of the battery. 3. Maintenance-free batteries have plate
groups like conventional batteries, but the
Also note on these batteries the state of groups are constructed differently.
charge indicator. To date this indicator is Another difference is that the plates are
found only on Delco batteries. The indicator is
enclosed in envelopes that act as the
a built-in hydrometer having a small green separators and also collect sediment as
the plates crumble with age (Figure 8-44).
ball that floats when the gravity of the elec-
trolyte IS 1.225 or higher. The indicator should The envelopes are bonded together and
not be used as a quick and easy way of telling permit the element to be placed on the
if the battery is good or bad, charged or bottom of the case. In contrast. the
discharged. It must be read according to con- element in a conventional battery is raised
ditions set down by the manufacturer in the case to give room for sediment to
collect and not touch the plates. Having
the element rest on the bottom of the tank
Characteristics Of Maintenance-Free allows considerably more electrolyte to
Batteries cover the plates and thus battery ef-
ficiency is improved
1. Since the electrolyte IS sealed in, the bat-
tery has a life time supply of it. Thus the

126
 8:24 BASIC ELECTRICITY

STATE-OF-CHARGE INDICATOR
HEAT-SEALED COVERS
STAINLESS STEEL TERMINALS
FINGER GRIPS
LIQUID/GAS SEPARATOR

PLATE STRAPS AND TERMINALS

EXTRUSION-FUSION INTERCELL CONNECTION

EPDXY-ANCHORED PLATE ELEMENT
SEPARATOR ENVELOPE
ELEMENT ON FLAT CASE BOTTOM

Delco Dovtsion of
General Motors Corporation
(8-44)

CAPACITY RATINGS OF BATTERIES Reserve Capacity

#4
As was mentioned earlier, the factors in- The reserve capacity rating gives 4.e number
fluencing battery capacity. i.e.. the amount of of minutes a new fully charged battery will
current a battery can produce, are the num- deliver 25 amperes at 27'C while maintaining
ber. size and thickness of the plates and the a voltage of 1.75 volts per cell. Since 25 amps
quantity and strength of the electrolyte. New is the power drain required to keep ignition,
capacity ratings for batteries were adopted in lights and other electrical accessories going.
1971 by the Society of Automotive Engineers what this rating indicates is how long the
(SAE) and the Battery Council International. vehicle will operate if the generator or alter-
nator fails. in other words, if the charging
Batteries are given two ratings: system of the machine breaks down, how
cold power rating many minutes do you have to seek help?
be reserve capacity

Cold Power Rating VARIATION IN BATTERY EFFICIENCY

OR TERMINAL VOLTAGE
Cold power rating gives the amount of power
the battery has for starting on cold days; this Battery voltage is not constant; a 12-volt bat-
rating is the number of amperes the battery at tery does not deliver 12-volts at all times.
-18 C (0 F.) can deliver over 30 seconds and Three main factors affect the terminal voltage
not fall below a voltage of 1.2 volts per cell. of a battery:
the minimum voltage required for dependable temperature
starting.
operating cycle (charging or
The cold power rating is the more important of discharging)
the two ratings because it deals with the bat- state of charge
teries main lob. starting. Many low priced bat-
teries can deliver only 200 amps: more power- Temperature
ful batteries will deliver 525 amps under the
same conditions The cold power rating of the A battery produces current by chemical reac-
battery should match the power requirements tions. by sulfuric acid acting on the positive
of the engine it has to start If an engine under and negative plates. At lower temperatures
cold conditions required 400 amps to start, ob- the chemicals don't react as fast and
viously the cheaper battery delivering only therefore the battery has a lower voltage. The
200 amps would be inadequate. effect of temperature on terminal voltage is

127
 BASIC ELECTRICITY 8:25
,i

illustrated in Figure 8-45. At 27 C a battery is State of Charge

100% efficient; it has full cranking power. At
-39 C a battery is only 30% efficient. Since The higher a battery's state of charge (up to
the engine is harder to turn over in cold tem- maximum charge). the greater is its terminal
peratures, the net effect of temperature on voltage.
Starting is that as it gets colder the battery be-
comes smaller while the engine becomes POINTS ON BATTERY USE
larger. AND REPLACEMENT
Centigrade
1. When replacing batteries, be sure to
replace the battery with one at least equal
in capacity to the original.
1011%
2. A larger battery than the original may be
needed if accessories such as an air con-
1 ditioning unit are added to the vehicle's
electrical circuit.
165%
68% 3. A high-output generator may be needed in
cases where electrical loads are ex-
cessive or where a vehicle operates
2511% mostly at idle speeds. This high-output
46% generator will help keep the battery
charged and increase its service life.
M. The cheapest battery is not always the
311% 3511%
best buy. For example, three batteries in
the same group size may vary in price. but
they also vary in cold power rating. in con-
struction and in warranty period. Divide
the price by the months of warranty and
(8-45) you may find the most expensive batteries
are really the cheapest per month of ex-
HOW COLD WEATHER AFFECTS THE BATTERY
AND THE ENGINE WHEN STARTING pected service.
Courtesy of John Deere Ltd 5. A final word on replacing batteries: one
Starling difficulties may occur during hot out of every four batteries returned for
weather after a machine has been worked and warranty has nothing wrong with it except
the engine is hot Difficult hot starts are more that it is discharged. Be sure to check
common with large. high compression whether a battery can be recharged
engines. An air conditioning unit is also a before thinking about replacing it.
contributing factor. The point here is that you
cannot use a lower capacity battery when a
machine is working in a warm climate. The PREVENTIVE MAINTENANCE ON
same size battery as the machine would have BATTERIES
in a cold climate must be used.
Visual Inspection
Operating Cycle (Charging or Discharging) A battery should be visually inspected during
the daily-walk-around check. and also in-
When a battery is being charged. its terminal spected at any time that scheduled main-
voltage increases. the amount of increase tenance is done on the battery. Points to look
depends on the charging rate. Note that for are:
regulators are required on charging systems
to control the voltage increase so that the bat- 1. Inspect the battery case for cracks and
tery is not overcharged. When a battery is leaks. A leaking battery should be
discharging. its terminal voltage decreases. replaced. Before putting in a new battery
the amount of decrease depends on the wash down the battery box with a solution
discharging rate. of water and baking soda.

128
8:26 BASIC ELECTRICITY

2 Inspect battery posts. clamps and cables Any problems found during the battery in-
for breakage, loo'ae connections. spection should be attended to immediately. If
corrosion. a battery case is damaged and leaks, the bat-
tery will have to be replaced. Before installing
3. Note whether the top of the battery is a new one, thoroughly wash the battery box
clean and dry. Dirt and electrolyte on top with a solution of baking soda and water. This
of the battery causes excessive self- will neutralize any acid that has leaked from
discharge.
the battery. Similarly. corroded battery cables
4. Nothing will damage a battery quicker should be removed from the battery and
than allowing it to jump around. 8e sure washed in a baking soda solution. When
the battery carrier is solidly mounted and reconnected they should be coated with an
in good condition and that the hold-down anti-corrosive agent such as a spray or a
firmly grips the battery. Also look for any small amount of grease. Hold-downs that are
bolts protruding into the bottom of the bat- loose or missing must be repaired. Also watch
tery box. for bolts protruding in the bottom of the bat-
tery box. Placing a thin sheet of plywood un-
5. Inspect the battery for raised cell covers der the battery is always a good idea.
or a warped case, either of which may in-
dicate the battery has been overheated or
overcharged.

DIRT ON TOP OF BATTERY

PLUGGED VENTS

CORROSION
,; 11111P
si
%IV
I
LOOSE CABLE
OR POST

NW.

CRACKS

LOW WATER LEVEL

(8-46)

129
 BASIC ELECTRICITY 8:27

Checking and Adding Water

(This information will of course not apply to
w maintenance-free batteries.)
Of the four chemicals in a conventional bat-
tery lead, lead peroxide. sulphuric acid and
water water is the one that has to be (8-47)
replenished. The usual recommended interval AUTOMATIC FILLER
for checking a battery is every 30 hours of
operation or 1,000 miles. During warm
weather, checks may be required more often.
Evidence of large amounts of condensation
on the top of the battery and low electrolyte
level can Indicate an overcharging condition.
if this problem continues to occur, have the
charging system checked.
Fill the battery with clean water, preferably
distilled water. In any case, avoid usinq water
that has a high mineral content as the mineral
will ultimately shorten the life of the battery.
Fill only to the bottom of the fill hole; any
higher will cause unnecessary spillage. Avoid Removing, Cleaning and Installing Batteries
spilling water on the battery top and use a
paper towel to dry the top when completed. When removing a battery or batteries. follow
Figure 8-47 shows two types of battery fillers. these recommendations:
1. If multiple batteries are used, make a
diagram of the circuit so that you can
correctly reconnect the batteries.
2. Disconnect the ground cable first, using a
box wrench to loosen the terminal bolts.
Use a terminal puller to remove the
cables; do not hammer on the battery
posts When installing the battery, con-
nect the ground strap last. A terminal
puller is shown in Figure 8-48.

(8-48)

TERMINAL PULLER

130
8:28 BASIC ELECTRICITY

3. Remove the battery holddowns and

carefully lift the battery out. The method of
lifting will depend on the location and size
of the battery. For conventional batteries
with lead posts, a carrying strap (Figure 8-
49) is the safest method.

STRAP CARRIER
(8-49)

Whatever the method of lifting out the bat-

tery, be careful not to drop it because the
case easily cracks. Try to keep the battery
clear of your clothing since battery acid
eats through cloth.
4. Clean the battery with a solution of water
and baking soda, then dry it. Clean the
terminals with a terminal brush or scrape
them with a knife or screwdriver. Clean
the cables in a similar fashion.
5. When installing the battery, use caution
not to over tighten the hold-down as it
could crack the case. It is a good practice
to protect the bottom of the case with a
thin piece of plywood.
6. Make sure that the cables sit down on the
posts (Figure 8-50). Coat the cables with
an anti-corrosive agent such as grease or
vaseline. Anti-corrosive sprays are also
available.

INCORRECT CORRECT

TERMINAL
CLAMP

CASE

(8-50)

131
 BASIC ELECTRICITY 8:29

BATTERY QUESTIONS 11. What provision is made within a main-

tenance-free battery to permit the
1. The current a battery will produce elements to be placed on the bottom of
depends upon chemical reactions within the case?
the battery between the sulphuric acid
and both the sponge lead in the negative 12. What claims are made of maintenance-
plate, and the: free batteries?
(a) lead sulphate in the positive plate 13. What three factors affect batteries' ter-
(b) lead acid compound in the positive minal voltage?
plate 14. What are the two ratings given to bat-
(c) lead peroxide in the positive plate teries and briefly explain each.
(d) lead zinc in the positive plate 15. Tare or False? At lower temperatures
2. Basically what does the element in a bat- battery chemicals react faster and
tery cell consist or? therefore the battery has higher voltage.

3. When does this battery element become 16. When selecting a battery, the cold power
a cell? rating should match

4. Each cell of a lead-acid battery is 17. The presence of dirt and electrolyte on
capable of producing approximately how
much voltage? top of the battery causes excessive
(a) 3 volts
18. To neutralize spilled battery electrolyte
(b) 1 volt (a necessary safety precaution) a
(c) 2.6 volts mechanic should keep on hand a quan-
(d) 2 volts tity of:
5. True or Faise? The positive post of a (a) distilled water
battery is the larger of the two. (b) baking soda
6. The electrolyte in a fully charged battery (c) sulphuric acid
has a specific gravity at 80°F. of ap- (d) vaseline
proximately:
19. Of the four essential chemicals in a lead-
(a) 1.380 acid battery which one has to be
(b) 1.160 replenished occasionally?
(c) 1.250 (a) lead
(d) 1.270 (b) lead peroxide
7. True or False? When a battery be- (c) sulphuric acid
comes discharged the two plates be- (d) water
come chemically similar thus accounting
for the loss in cell voltage. 20. When removing a battF y you should
first:
8. When a battery is discharged the elec-
trolyte has an increased percentage of. (a) disconnect the insulated terminal
cable
(a) sulphur
(b) loosen the battery hold-down
(b) sulphuric acid
(c) disconnect the grounded terminal
(c) water cable
(d) hydrogen (d) drain the electrolyte
9. Briefly state the advantage of a dry-
charged battery over a wet-charged one.
10. Is a maintenance-free battery dry or wet-
charged/

132
8:30 BASIC ELECTRICITY

21. A good practice to prevent corrosion and

bad connections when reinstalling bat-
tery cables is to:
(a) make sure they are clean and dry
(b) make sure they are properly
tightened
(c) coat them with grease or vaseline
(d) all of the above are necessary

133
 BASIC ELECTRICITY 8:31

BATTERY TESTING produce a high current flow. Yet when tested

with a hydrometer the battery could give a
A battery must supply a flow of current and good specific gravity reading. Hydrometer
maintain a voltage Tests can be carried out readings on old batteries can also be decep-
that will tell if a battery is doing its job The tive. The old battery could maintain an even
tests for conventional batteries and the tests specific gravity reading, say 1.235, but it may
for maintenance-free batteries will be not be able to produce an adequate amount of
discussed separately. Four tests are used on current.
conventional batteries:
Below are the procedures for making a
1. Hydrometer for specific gravity. specific gravity reading on a battery with a
2. Load tester capacity test. hydrometer.

3. Light load test individual cell voltage. Caution: Always have a paper towel handy
to hold over the end of the
4. Three minute last charge test. hydrometer when it is lifted from
the cell. A paper towel is better
The state of the battery must be considered than a rag because the towel will
when deciding what test to use. Questions be discarded whereas the rag is
such as these would be asked: was water ad- likely to be left around or put into
ded before testing? Is the battery charge par- an overall pocket and the acid will
tially down or is it completely dead/ Not all of quickly eat the cloth. Be very
these tests are required to fully test a battery. careful not to spatter acid on your
Usually two tests will give a fair indication of skin or worse still to get it in your
the battery's condition. eyes. If acid contacts the skin,
rinse the contacted area with run-
Hydrometer Test ning water for 10 to 15 minutes. II
A battery hydrometer (Figure 8-51) works on a acid splashes into the eyes, force
principle similar to the antifreeze-testing the lids open and flood the eyes
hydrometer discussed earlier. Electrolyte is with running water for 10 to 15
drawn into the hydrometer's sight glass and minutes. Then see a doctor at
the float in the glass rises to a level of specific once. Don't use any medication or
gravity. This level indicates the strength of the eye drops unless prescribed by a
battery's charge. Good hydrometers have a doctor.
thermometer built into them to give a tem-
perature correcting factor. Battery Specific Gravity Test:
hydrometers. it should be oointed out. will not 6 and 12 Volt Batter!
be used on the new mail -.---rice-free bat- Note: If water has been recently added to a
teries because the electrolyte in these bat- battery, a hydrometer will not give an
teries is sealed in. accurate reading of the battery's state
of charge.
SQUEEZE BULB 1. Using a hydrometer, remove enough elec-
GLASS TUBE BASE PICK-UP trolyte from one cell to allow the float to
FLOAT TUBE move freely without touching the top or
bottom. Hold the hydrometer vertically to
prevent the float from touching the sides
of the barrel.
R 45$ THERMOMETER
2. With your eye level with the float take the
float reading and record ft.
(8-51) HYDROMETER
Courtesy or John Deere Lid 3. Note the electrolyte temperature:
If the battery temperature is not at 27 "C.
Hydrometers are the most common battery add 4 points (.004) soecific gravtiy to the
tester found in shops. Although a hydrometer float reading for each 5- above 27"C, or
can give a fairly good indication of a battery's subtract 4 points (.004) specific gravity
condition, the, are not foolproof. For example, from the float reading for each 5' below
a battery could have a poor internal con- 27". Most good hydrometers have a tem-
nection between the cells making it unable to perature corrected scale.

134
 8:32 BASIC ELECTRICITY

4 Repeat the above test on all remaining 6. Determine the battery's state of charge by
cells. locating its specific gravity on the Per-
centage of Charge Table below.
5. Note the amount of variation in the cell's
specific gravities.
Unless otherwise specified, all cell Percentage of Charge Table
4 readings should be within 30 points (.030).
If cell variation exceeds this amount, an Fully charged specific gravity varies in dif-
unsatisfactory condition is indicated. Fur- ferent types of batteries. Typical values
are given below:
ther tests should be performed.
Standard Specific Specific Gravity in Specific Gravity as
State of Gravity as Used in Cells Built with Used in
Charge Temperate Climates Extra Water Capacity Tropical Climates

Fully charged 1.280 1.260 1.225

75% charged 1.250 1.230 1.195

50% charged 1.220 1.200 1.165

25% charged 1.190 1.170 1.135

Discharged 1.130 1.110 1.075

TEMPERATURE
CORRECTED
SCALE
(8-52)

TEMPERATURE CORRECTED HYDROMETER

135
 BASIC ELECTRICITY 8:33

Load Tester
A load tester gives the truest picture of a bat-
tery's condition. if the specific gravity is 1.225
or better. a load test (capacity test) can be
done on the battery. If. however. the specific
gravity is less than 1.225. then a light load test
(a test of the individual cells) will have to be
used Also. if water had to be added to the
cells at the time of testing. use the light load
test since you can't take the specific gravity
and know that it is 1.225 or better. Figure 8-53
shows a typical battery load tester or battery
starter tester

AMMETER

VOLTAGE
SELECTOR
SWITCH

w
AMMETER LEADS VOLTMETER LEADS

LOAD CONTROL
(8-53) KNOB

Courtesy of Sun Electric Corporation

136

.1-
8:34 BASIC ELECTRICITY

Typical Load Test Procedures

1. Connect the tester's ammeter and volt-
meter leads as shown in Figure 8-54A.

Courtesy of Sun Electric Corporation

2. Turn Control Knob clockwise until the Am- Light Load Or Individual Cell
meter reading is exactly three times the Voltage Test
Ampere Hour Rating of the battery. (Exam-
ple: 180 Amperes for a 6U AH battery.) A light load test is used rather than a load test
if the specific gravity of the electrolyte is less
3. Maintain the load for 15 seconds, note the than 1.225. This test is done with what are
voltmeter reading. and then turn the Con- called battery cell probes which are attachbJ
trol Knob back to OFF position. to the load tester voltmeter leads (Figure 8-
54B) with the voltmeter set on the 4 volt scale,
If the voltmeter reading was within the the voltage of each cell is tested and if a
green band, 9.6 volts for a 12 volt battery. variance of more than .1 volt between in-
or 4.8 volts for a 6 volt battery, or was dividual cells is found, the battery should be
higher, the battery has good output replaced. See the load tester instruction
capacity. Although the battery may pass manual for light load testing procedures.
the load test it may still require some
charging to bring it up to peak per-
formance.
Note: When cold, a battery has a lower
discharge capacity. If a cold bat-
tery fails to pass the capacity test,
let it stand until the battery tem-
perature reaches 27°C, and then
retest it.

STEEL
PROD
LEAD
CADMIUM CONNECTOR
PROBE

(8-54s, Courtesy of Sun Electric Corporation

137
 BASIC ELECTRICITY 8:35

Three Minute Fast Charge Test 2. Adjust the charging switch to obtain a
charge rate as close as possible to 40
The three minute fast charge test is done on a amps. for a 12 volt battery, or 75 amps. for
very low or dead battery (one that has failed a 6 volt battery.
the load test) and indicates whether the bat-
tery will accept a charge. The three minute 3. After three minutes. while the charger is
test can be done with equipment found in still operating on fast charge. observe the
most shops today a fast charger and an ac- voltmeter reading. If the reading is beyond
curate voltmeter. the green band or exceeds 15.5 volts on a
12 volt battery of 7.75 volts on a 6 volt bat-
Note that performing the three minute test on tery, the battery is sulphated or worn-out
a battery that has nearly a full charge will give and should be replaced.
an inaccurate reading. Below are a voltmeter
and a charger connected to a battery for a
three minute fast charge test.

Typical Procedures For A Three Minute Fast

Charge
1. Connect the voltmeter and the charger as
shown below.

40 161
0 **Ili**
)e
CH=
44 RED
CLIP (11=exicza
Potion
*serum

BLACK
CLIP

(8-55) Courtesy of Sun Ste:ono Corporation

138
8:36 BASIC ELECTRICITY

SUMMARY OF TESTING
CONVENTIONAL BATTERIES
1. Take the specific gravity reading and note
the result. No more than .030 points be-
tween cells is acceptable.
2. If 1.225 or better, do a Capacity or Load
test. At the end of 15 seconds. the voltage
should not be less than 9.6 volts for a 12
volt battery or 4.8 volts for a 6 volt battery.
If the battery passes these two tests. it is
considered to be satisfactory for service.
If a battery fails the load test, do a three
minute fast charge on it to see if it will
take a charge
3. If the specific gravity is less than 1.225
and there is not more than .030 volts be-
tween cells. perform a light load test. If
there is a variation of more than .1 volts
between cells, the battery is defective.
4 If the electrolyte is too low for a reading
and water is added to the cells. perform a
light load test.
5. If the battery is really low or dead. perform
a three minute fast charge test on it. If the
voltage does not exceed the maximum
limit (see fast charge instruction manual).
do a light load test to finalize the
diagnosis. If the voltage exceeds the
maximum limit in three minutes, it usually
indicates that the battery is sulphated or
old.

139
 BASIC ELECTRICITY 8:37

TESTING MAINTENANCE -FREE BATTERIES Step 2: Remove Surface Charge

Since the electrolyte is sealed into main- Connect 300-ampere load across terminals for
tenance-free batteries, obviously a specific 15 seconds to remove surface charge from the
gravity test or a light load test can't be used. A battery. If maintenance-free battery is in
load test, therefore, is the test used on main- vehicle. connect to terminals. If out of vehicle.
tenance-free batteries. Below are testing attach load clamps to adapter charging tool
procedures recommended by Delco for their as shown (Figure 8-57). For Delco 1200,
maintenance-tree batteries. remove cables. attach load alligator clamps to
contact lead pad as shown (Figure 8-58).
Step 1: Test Indicator (Figure 8-56) INSULATOR STRAP
PREVENTS TOOL SEPARATION
1. Green Dot Visible AND LOSS WHEN NOT IN USE
Proceed to Step 3. Note: On rare oc-
casions. after prolonged cranking, the
green dot may still be visible. Should this
occur. charge battery as described in
"Battery Charging Procedures" section.
then proceed to Step 2.
2. Dark Green Dot Not Visible
Charge the battery as outlined under "Bat-
tery Charging Procedures" section aad
proceed to Step 2.
On rare occasions. the test indicator may turn
sight yellow. in this instance the battery
should not be tested. Replace the battery.

ADAPTER CHARGING
TOOL ATTACHED
TO TERMINALS
(8-57) Courtesy of Delco Division of
General Motors Corporation

BATTERY CHARGE BATTERY CHARGE BATTERY CHARGE UNKNOWN,

OK, FLUID LEVEL OK: LOW, FLUID LEVEL OK: FLUID LEVEL LOW:
BATTERY TOP BATTERY TOP BATTERY TOP

-.............
4.--.............i1r...00
Darkened Indicator
WITH GREEN DOT Darkened Indicator LIGHT OR BRIGHT
NO GREEN DOT INDICATOR, NO GREEN DOT
.."---........msio---gimmilm- -----.----,----.......---
CAN BE JUMP STARTED, (8-56) DO NOT JUMP START,
TESTED OR CHARGED TEST OR CHARGE
*CHARGE MAY STILL BE SUFFICIENT TO START VEHICLE Courtesy of Delco Division
of General Motors Corporation

140
8:38 BASIC ELECTRICITY

IMMO
4111111MI

IP w"--"ag-

i 1
HEX NUT ALLIGATOR CLAMPS ALLIGATOR CLAMPS
LEAD PAD
I
HEX NUT
i
LEAD PAD (8-58)
ALLIGATOR CLAMPS CONTACTING LEAD PAD FOR TESTING AND CHARGING DELCO 1200 BATTERY

Counesy 01 Delco Division of

General Motors Corporation

Step 3: Load Test

1 Connect voltmeter and specified load across terminals.

MODEL LOAD* MODEL LOAD*

49-5 210 Amperes 85-4 130 Amperes

55-5 180 Amperes 85.5 170 Amperes
59-5 210 Amperes 87-5 210 Amperes
71-5 230 Amperes 89-5 230 Amperes
81-5 230 Amperes 1200 235 Amperes

* See -Charging and Testing Adapters' section

2. Read voltage after 15 seconds with load connected. then disconnect load.
3. If minimum voltage is 9.6* * or more, battery is good.

----
4. If minimum voltage is less than 9.3* *, replace battery.
* * This voltage is to be used for battery ambient temperatures of 70 F and above For tem-
peratures below 70 F, use the following:
(21 C)
70 F & (16 C) (10'C) 4 '0) (-1 C) ( -7'C) (-12 C) (-18'C)
Above 60 F 50 F 40 F 30'F 20'F 10'F O'F
Minimum Voltage
9.6 9.5 9.4 9.3 9.1 8.9 8.7 8.5

141
 BASIC ELECTRICITY 8:39

QUESTIONS BATTERY TESTING

1. The chemical energy within a battery can
be determined by the use of:
(a) a hydrometer
(b) a voltmeter
(c) an ammeter
(d) an ohmmeter
2. When testing the specific gravity of a
battery. the allowable variation between
cells should not exceed'
(a) .060
(b) .010
(c) .300
(d) .030

3. A typical load or capacity test of a 12-volt

battery requires that 180 ampere load be
applied for 15 seconds and that the
voltage must not fall below:
(a) 6.9volts
(b) 9.6 volts
(c) 11.1 volts
(d) 8.6 volts
4 When doing a light load or individual cell
voltage test. the allowable voltage dif-
ference between cells should not ex-
ceed:
(a) volt
1

(b) .5 volts
(c) .01 volt
td) 25 volts
5. True or False? A three minute fast
charge must only be done on a low or
dead battery and tells whether or not the
battery will accept a charge.
6. What is the recommended test for main-
tenance-free batteries?

142
8:40 BASIC ELECTRICITY

CHARGING BATTERIES CHARGING CONVENTIONAL BATTERIES

While an engine is running, the battery is Time is usually the main factor when deciding
charged by the generator. Eventually, whether to fast charge or slow charge a bat-
however. the battery charge wears down and tery. Obviously. it's better to slow charge a
if not attended to it won't have enough power battery because you get a mom thorough
to start the engine. When a battery's state of charging job (fast charging takes place only
charge is low. it should be recharged. The on the surface of the plates). However, you
recharging can be done while the bat.Jry is in don't always have the time (24 to 48 hours) to
the vehicle or it can be taken out. do a slow charge, and in such cases fast
charges have to be done.
There are a number of different battery
chargers, but they can be classified under two Slow Chargers
general types.
Constant Current Chargers
Constant Current Chargers
A slow charger can be either constant current
A constant current charger does just what its or constant voltage (constant current,
name implies, supplies a constant or set however, is most common). The constant
amount of current to the battery. The recom- current charger in Figure 8-59 is charging
mended charging rate is 1 amp per positive three 12-volt batteries connected in series.
battery plate per cell; e.g., if a battery has five
positive, plates per cell, it should be charged
at 5 amps. Most batteries that are slow
charged with a constant current charger will
take five to six amps
Constant Voltage Chargers
A constant voltage charger supplies the bat-
tery with a constant voltage during the
charging period, for example, 15 volts for a 12-
volt battery. This charger will charge the bat-
tery at a fairly high amperage when the bat-
tery is low. and then as the battery builds up
charge the amperage tapers off, almost to (8-59)
nothing as the battery becomes fully charged CONSTANT CURRENT SLOW CHARGER
Constant current are much more common Courtesy of John Deere Ltd
than constant voltage chargers.
Chargers have printed on them tne maximum
Chargers can be either (1) slow charge's. (2)
number of batteries that they can charge, e.g.,
fast charger or (3) trickle chargers. or they five 12-volt batteries (total 60 volts) and ten 6-
can be a comb:nation of these.
volt batteries (total 60 volts).
Slow chargers are used to completely
recharge a dead battery: they can take up to
48 hours. Fast chargers are used for a quick The example shown would have the voltage
boost (from 114 hour to 1 hour) and won t do control set at 36 volts (3 x 12), and the charge
as complete a job as slow chargers. Some rate control set at approximately one amp per
chargers have the dual capacity to provide positive plate per cell, usually five to six amps.
either a fast or slow charge. When there are a number of batteries of dif-
ferent sizes on the charger, average out the
Trickle chargers are used to keep a battery charge rate. On some of the new chargers,
up to full charge. they are especially good for you don't have to bother counting or
batteries that are little used or for wet charged averaging out the positive plates. These
batteries being stored chargers have a yellow, green and red band
on the charge rate indicator and recommend
the control be set to stay in the green range.

143
 BASIC ELECTRICITY 8:41

To connect a constant current charger start ( -) post of the first battery. Then take the red
with the black lead (negative) from the lead ( positive) from the charger and connect it
charger and connect it to the negative post of to the positive (t) post of the first battery. Now
the first battery Then take the red positive using good jumper cables connect up the bat-
lead from the charger and connect it to the tery's negative to negative and positive to
positive post of the last battery. Now using positive.
good jumpers. connect the batteries, positive
to negative to complete the series circuit. As with a constant current charger. check the
specific gravities of the charging batteries
Recheck all the connections by turning the twice a day and remove the batteries when
connectors slightly on the posts. Finally turn they are fully charged.
the charger on and adjust it to the correct
charge rate. Fast Chargers
The state of charge of a battery being Fast chargers will give a battery a high
charged should be checked with a charge rate for a short period of time. usually
hydrometer twice a day if possible. The total no more than an hour. They are portable
charging time wit, vary depending on the (Figure 8 .61) in contras; to slow chargers that
strength of the charge to begin with, but at the are usually mounted on a wall or sit in the
end of 48 hours batteries should be fully same position on a be nch. Portable fast-
charged If a battery becomes fully charged chargers can charge a battery while it is in
(i e . its specific gravity is 1.275 or over) before the vehicle. Generally. only one battery at a
48 hours is up. remove it. time is charged on a fast charger. Note that
many modern fast chargers have a capacity to
Constant Potential (Voltage) Chargers slow charge a battery as well.
Constant potential chargers are connected to
batteries in parallel as shown in Figure 8-60.
The maximum number of batteries a charger
can handle will be marked on the charger.

(8-61)
(8-60)
Courtesy of John Deere Ltd
Courtesy of John Deere Lid

The voltage control is set at a specified

voltage. e.g..15 volts for a 12-volt battery. The
charge rate is automatically sensed by the
charger: the rate will be high when the
discharged battery is first connected to the
charger and will gradually taper c 3 as the bat-
tery becomes fully charged.
When connecting up batteries in parallel to a
constant voltage charger. start with the black
lead (negative) and connect it to the negative

144
8:42 BASIC ELECTRICITY

POINTS TO WATCH FOR WHEN 7. Charger settings:

FAST CHARGING
Voltages:
1. Whenever a battery charged.
is (a) on a constant slow charger set the
especially last charged. never allow the voltage to match the number of volts
electrolyte to exceed 51 C (125 F). in the batteries you are charging.
Overheating. in effect overcharging. can
drastically shorten the life of a battery. (b) on a constant potential charger set
The temperature on conventional bat- the voltage for a 12-volt or 6volt
teries can be taken with the hydrometer battery(ies).
thermometer. The rubber case of main- (c) on a fast charger set the voltage for
tenance-free batteries will be hot to the a 12-volt or 6-volt battery.
touch when the electrolyte reaches 51 C.
Amperage:
2. Watch the color of the electrolyte when (a) on constant current slow charger
fast charging batteries. As a battery ages set amperage to one amp per
the electrolyte will become discolored by positive plate per cell (usually five
sediment. During a fast charge the to six amps); or if the charger has a
sediment is stirred up and could get trap color indicator set it in the green
ped between the plates. causing a short. band.
If such a short occurs lower the charge
rate. (b) on a constant potential charger
there is no current setting.
(c) on a fast charger set the amperage
SUMMARY OF GOOD PRACTICES to either a high or low setting.
WHEN CHARGING BATTERIES
8. Charging Time:
1. Before connecting conventional bat-
teries to a charger make sure: (a) When stow charging a battery do a
specific gravity check twice a day to
(a) the battery tops are clean see if the battery is fully charged.
(b) the electrolyte is up to the correct Do not go on charging a fully
level charged battery.
(c) the caps are loosened or removed to (b) Set the fast charge time 1/4 hour to
allow the gases formed during 1 hour. Watch that the battery does
charging to escape. not overheat.
2 All chargers. slow or fast. need 110 volts 9. Always turn the charger off before
alternating current supply. disconnecting it to prevent any sparks
from accidentally igniting explosive
3 Always make sure a charger is turned off hydrogen gases given off during
when connecting it to a battery. Also charging.
when charging a battery while it is in the
vehicle, turn off all electrical ac-
cessories.
4. Disconnect the battery cable before fast
charging the battery in the machine. This
is especially important with AC charging
systems where the alternator can be
damaged.
5 When cc.inectrng any charger. observe
the correct polarity negative to
negative and positive to positive. Most
chargers today are polarity protected.
6 Make sure connections are solid before
turning on the charger.

145
 BASIC ELECTRICITY 8:43

, 411'.

11 .1111.*41.-

*It- P 32
,A7,v

.,

ls;

(8-62) Sparks or flames near a battery that is being charged may ignite explosive
gases causing a dangerous explosion.
Courtesy of Delco Division of
General Motors Corporation
10. Never charge a battery in a place where
there maybe any chance of sparks, e.g..
in any area where welding or grinding is
done (Figure 8-62).

11. Check with the hydrometer thermometer

to see that the electrolyte does not ex-
ceed 51°C. On maintenance-free bat-
teries touch the battery case to see that
it is not hot.
12. Recheck the electrolyte level on com-
pletion of the charge.

146
8:44 BASIC ELECTRICITY

CHARGING MAINTENANCEFREE
BATTERIES
Maintenance-free batteries are charged with
conventional battery charging equipment.
One manufacturer's recommendations for
charging their maintenancefree batteries are
given in Figure 8-63. Note the difference in
charging times compared with conventional
batteries the slow charging rate for main-
tenance-free batteries is less than that for
conventional batteries. and vice versa the Iasi
charging rate is longer.

12 VOLT MAINTENANCEFREE BATTERY CHARGING GUIDE (Defeo)

DO NOT CHARGE A BATTERY IF THE GREEN DOT IS VISIBLE
NOTE On rare occasions following prolonged cranking. .he green dot may still be
visible Should this occur. a boc ^targe of 20 ampere-hours is recom-
mended
DO NOT CHARGE A BATTERY IF THE TEST NDICATOR IS LIGHT YELLOW.
DISREGARD IT

(Stop charging when the green dot appears or

when the maximum charge shown below is reached)

Constant Current
Battery Model Slow Charging Rate Fast Charging Rate
55-5. 85-4. 85-5 5A ft 10 Hours 20A 0 2% Hours
10A ft?.. 5 Hours 30A #i 1% Hours

49-5: 59-5 5A is 15 Hours 20A 'l 33/4 Hours

71-5. 81-5 10A '4,% Ph Hours 30A 13: 2% Hours
87-5. 89-5: 1200 40A d 2 hours
50A .@ 1% Hours

To avoid DAMAGE. the charging rate must be reduced or temporarily halted d

1 The battery case feels hot (51 C).
2 Violent gassing or spewing of electrolyte occurs.
After charging in accordance with the tables. even though the green do1 does no'
appear. the battery is still sufficiently charged for testing.

(8-63) Comesy of Delco Division of

G...erat Motors Corporation

-147
 BASIC ELECTRICITY 8:45

JUMPER CABLES
When a charger is not available, a common
practice to start a vehicle with a dead battery
is to use Jumper cables and a battery pack.

Good Practices When Jumping

1 Before connecting jumper cables be sure
all tne electrical accessorie3. lights, radio.
wipers, etc. are off.
2. Observe voltage when Jumping. Jump a 6-
volt battery with a 6-volt battery. not a 12-
volt as arcing (electricity lumping across
a gap) could occur. bringing with it the
danger of tire.
3. Observe polarity when jumping. Connect
the jumper cables negative to negative
and positive to positive (since you are just
replacing the existing power source).
Connect the cables in this order:
(a) connect one cable clamp to the
positive terminal of the dead battery
and then connect the other end to the
positive terminal of the booster bat-
tery.
(b) connect the second clamp to the
negative terminal of the dead battery
and then connect the other end to the
negative terminai of the booster bat-
tery. Wrong polarity will cause arc-
ing.
4. When removing the cables be sure to
keep tl,e clamps separated until they are
disconnected from the source. if they get
too close arcing could occur
5. Never use a fast cnarger as a booster to
start an engine.
6 Maintenance-free batteries have jumping
procedures tnat can differ from jumping a
conventional battery. Check the marufac-
turer's recommendations.
7. Use the shortest cables possible because
the longer the cables tne more the voltage
drops.
8. Maintain good clamps on the jumpers to
ensure the best possible connection with
_of
a minimum voltage drop.

148
 8:46 BASIC ELECTRICITY

QUESTIONS BATTERY CHARGING 8 Compared to a conventional battery. a

maintenance-free battery when fast
1 The recommended slow charging rate for charged requires'
a battery is one amp per positive plate
per cell If you have a 15 plate 6-volt bat- (a) a longer charge
tery, i.e.. 15 plates per cell. what would (b) a shorter charge
be the correct charge rate?
(c) about the same
(a) 15 amps
(d) a very low charge
(b) 7 amps
9 A charger should be turned
(c) 8 amps before connecting it to a battery.
(d) 45 amps
10. True or False? When boosting with jum-
2 Which does a better job of charging a per cables doubling the voltage of the
i
battery. a fast charger or a slow charger? boosted battery is permissible provided
Briefly explain why that the polarity is the same and the
cables are quickly removed after the
3 Wt. slow charging batteries on a con- boost is given.
stant current charger connect the bat-
teries in
(a) parallel
(b) series
(c) series or parallel
4 What are the two important things to
watch for when fast charging a battery?
5 Care must be taken while working near
batteries that are charging because a
spark could explode the
gases being given 011 from the charging
process
(a) nitrogen
(b) hydrogen
(c) carbon dioxide
(d) helium
6 True or False? Overcharging a battery
doesn't hurt it.
7 When fast charging a battery in a vehicle
with an AC charging system, it is a good
practice to
(a) remove the fan belt
(b) keep the charge rate low
(c) disconnect a battery cable
(d) disconnect the voltage regulator

149
 BASIC ELECTRICITY 8:47

BASIC STARTING CIRCUIT

A basic starting circuit has four parts (Figure
8-64):
The Battery supplies energy for the cir-
cuit.
2. The Starter Switch activates the circuit.
3. The Starting Motor Switch connects the
battery to the starter motor and in some
cases engages the motor drive with the
engine flywheel.
4. The Starting Motor drives the flywheel to
start the engine.

MOTOR SWITCH

p BATTERY
STARTER
SWITCH
STARTING
MOTOR
-;

w (8-64) BASIC STARTING CIRCUIT

FLYWHEEL
MI

K Courtesy 01 John Deere LW

The starting circuit converts battery electrical The current received by the solenoid moves
energy into starting motor mechanical energy the solenoid plunger and engages the pinion
to crank the engine. How cio the four basic with the flywheel (Figure 8-66)
parts c! the starling circuit work together to
start a vehicle? When the starter key is turned KEY SWITCH
on by the operator. a small amount of elec-
trical energy flows from the battery to the
solenoid and back to the battery through the
ground circuit (Figure 8-65)

SOLENOID

STARTING MOTOR
X 1361

(8-66)
Courtesy 01 John Deere Ltd

(8-65) Courtesy of Jonn Deere Ltd

150
 8:48 BASIC ELECTRICITY

The plunger also closes the switch inside the To increase the strength of the magnetic field
solenoid between the battery and starting between the pole pieces. wrap a wire over the
motor completing the circuit and allowing a poles and pass a current through it. This wire
large amount of electrical energy to flow into is called a field winding (Figs st 8-69).
the starting motor The starting motor rotate:
the pinion which in turn rotates the flywheel to
crank the engine (Figure 8-67).

tS

(8-69)
FIELD WINDING
X I.3e6
Courtesy of Jonn Deere Ltd
Now take a loop of wire and pass a current
STARTING MOTOR 1mr
through it A circular magnetic field is formed
Ft 1;e: around the wire. Note the direction of the
(8-67) STARTING CIRCUIT IN OPERATION
electromagnetic field (Figure 8-70).
3) STARTING MOTOR CRANKS ENGINE
Courtesy of John Deere Ltd

In the basic starting circuit above a solenoid

switch was used. There are other types of
starting motor switches which will be
CURRENT
discussed later. FROM
BATTERY
THE STARTING MOTOR
The starting motor cranks the engine. Per-
forming this heavy job requires a special type
MAGNE TIC Fl ELO
of electrical motor that must:
Courtesy of Jonn Deere Ltd
1. Operate for short intervals under great A hiee
overload.
2. Produce very high horsepower for its size. Placa the loop of wire in the magnet; field be-
twpon the pole pieces and pass a current
To give the principles of a starting motor a through the wire (Figure 8-71).
basic ele:tric motor is constructed below:
First start with two pole pieces. The poles set
up a magnetic field between them running in
a direction from north tr south (Fie:re 8-68).
POLE PIK'S

Courtesy of Jonn Deere Ltd

MAGNETIC "N...
FIELD

Courtesy of John Deere Ltd

X 451
 BASIC ELECTRICITY 8:49

Recall from the earlier discussion on elec- So far the loop (armature) has moved But it
tromagneticism the roinciple that a current must do more than move, it must rotate Here's
carrying wire with its surrounding magnetic where the commutator and the brushes come
field has a tendency to move from a strong to in (Figure 8-73) Attached to each end of the
a weak magnetic held Look at the field pat- loop is a split ring half, These half rings are
terns w hen the loop cuts through the the commutator Resting against these nngt
magnetic field (Figure 8-72) are two blocks of copper compound called
brushes The brushes are connected to the
*%kMirrilt?,,,INJ111,,Vir,11,1, II d battery

COMMUTATOR
SPLIT RINGS
BRUSHES

(8-73)

Current comes from the battery to the brushes

(8-72' DIRECTION OF CURRENT via the held winding. The brush on the left-
hand side passes current to a commutator half
Lefthand side of loop: The lines of force of ring and the current travels through the loop
the loop run in a circular pattern. coun- out the other commutator split ring. to the
terclockwise The polar lines of force run in a other brush and back to the battery. As the
straight-line from north to south On the un- loop begins to move each brush slides on a
derside of the loop. the loop lines of force run commutator half ring. When the loop reaches
the same way as the polar lines of force the top of its circle. the brushes will slide from
creating a strong combined force However. one half ring to the other. Thus. the current
on the top side of the loop. the loop lines of will always enter on the left side and exit on
force run counter to or against the polar lines the right. and the loop will keep getting its
of force. cancelling each other out and push upwards on the lefthand side and push
creating a weak field downwaras on the rig hthand side. The result:
the loop keeps rotating in the same direction.
Now applying the principle that the wire will (Note that this explains why the commutator
move from a Strong to a weak field. the loop is ring is split. If it wasn't split the loop would
pushed upwards get pushed first one way and then the other.
and it wouldn't rotate.)
Righthand side of loop: The opposite of the
lefthand side occurs By looking at the lines of
force you can see that a strong field is
created on top of the loop and a weak field
underneath it Thu s the loop gets a pull down-
wards
Since the loop is pushed upwards on the left-
nand side and pulled downwards on the right-
nand side. it moves This loop represents a
simple armature Note that if the direction of
the current was changed in the loop. the loop
would move in the opposite direction
152
 8:50 BASIC ELECTRICITY

An actual starting motor will have not one. but Manual Switch
a number of loops. and each loop will be at-
tached to a section of the commutator ring A manual switch (Figure 8-76) is a simple
(Figure 8.74) handoperated device that opens or closes a
circuit Everytime you flick a light switch in a
room you are operating a manual switch.

HEAVY SWITCH

BATTERY
BRUSHES

(8-74) ARMATURE FOR STARTING MOTOR STARTING -

Courtesy of John Deere Ltd MOTOR

In summary. a starting motor has pole pieces x /3??

and field windings. an armature, brushes and
(8.76) A MANUAL SWITCH
commutator. and a drive shaft to carry the
Courtesy of Jonn Deere Ltd
rotary motion to the pinion and flywheel
(Figure 8-75)
The manually operated starting switch may be
mounted where it is directly accessible to the
operator. or it may be mounted on the starting
motor and made accessible by various
BRUSHES devices such as a hand lever

Magnetic Switches
A review of electromagnetism is necessary to
understand a magnetic switch and a solenoid
switch A current carrying coil. you remember.
POLE
PIECES
Ncis ;-,, magnetic field
SHAFT he electromagnetic field is made stronger by
FIELD WINDINGS
COMMUTATOR placing a soft iron core in the coil: the core
ARMATURE 1.,. has the same poiarity as the coil If the core
(8-75) ARMATURE AND BRUSHES IN has freedom to move and is placed at one end
STARTING MOTOR of ti coil, it will also assume the polarity of
the col (Figure 8-77)
Courtesy of John Deere LW

SWITCHES FOR STARTING MOTORS

-"-:-y "\,
Starting motors must be switched on to start
an engine, but must be immediately switched
off once the engine starts Four types of start-
ing motor switches are used
S
*kf (C
"JA i joPV rose v 4N
op
rate.,
co

et, t"" IMIMMIIMM.

11Atke-- CO L
:%:%?-7/
manual switch .s,':.:;LIZAI.3..g
magnetic switch -
solenoid switch
series-parallel switch (8-
CoL7a7ie)sy of John Deere Ltd

153

aInImMiler
 BASIC ELECTRICITY 8:51

Tnerefore. the ad;acent poles of the core and STARTER CONTROL SWITCH
coil have opposite polarity. and the core will
be drawn into the center of the coil when WINDING
current flows through it As soon as the PLUNGER
current stops flowing the field collapses and
MAGNETIC
the core is free to move away from the coil. SWITCH
Tnis movement of the core in and out of the
coil is the principle of operation of the
magnetic and solenoid switches BATTERY
RETURN SPRING TERMINAL
Tne magnetic switcn is mounted on the
starting motor frame like some manual swit- MOTOR
cries It is operated by a magnetic coil that is CONTACT DISK
TERMINAL
connected to the battery through a start con-
trol 3n the starter switch
BENDIX DRIVE
STARTING MOTOR
STARTER SWITCH
1380 TO BATTERIES

(8-79) A TYPICAL MAGNCTIC SWITCH CIRCUIT

MAGNETIC Courtesy of Jonn Deere Ltd
SWITCH
Solenoid Switch
The solenoid switch (Figure 8-80) is very
X 1379
similar to a magnetic switch. but in addition to
closing the circuit. the solenoid provides a
(8-78) MAGNETIC SWITCH CIRCUIT mechanical means of shifting the starting
Courtesy of Jonn Deere Ltd motor pinion into mesh with the flywheel ring
gear.

The magnetic switch works as follows: the RETURN SPRING

switch (Figure 8-79) has many turns of a small
wire wound around a hollow core. Floating in
the core is a plunger with one end acting as a
contact between the two main switch ter-
minals. These terminals are connected in SOLENOID
series with the starting motor. Usually a small SHIFT
spring holds the plunger away from the main LEVER
terminal contacts.
When the circuit to the coil is closed. a strong
magnetic field is created in the core. causing
the plunger to overcome the spring tension
and complete the circuit between the terminai
contacts. When the core contacts the ter-
minals. the main circuit to the starting motor
is completed and the engine is turned over.
When the engine starts and the control circuit
Is opened at the starter switch. the magnetic
held collapses and the spring forces the PINION
plunger to its original position. The starting
motor circuit is open and the starting motor
stops turning A 1391
(8-80) SOLENOID SHIFT LEVER
Courtesy of Jonn Deere Ltd

154
8:62 BASIC ELECTRICITY

The solenoid switch has two coils of wire The initial plunger movement engages the
wound in the same direction (Figure 8-81) drive pinion with the flywheel ring gear. Fur-
The pull-in winding is made up of heavy wire ther movement of the plunger closes the
connected to the motor terminal of the switch contact points within the solenoid, per-
solenoid and through the motor to ground mitting a heavy flow of current from the bat-
The hold-in winding has an equal number of tery into the starting motor to crank the
turns of line owe with one end connected to engine Note that this heavy flow of current
the ground These coils are energized directly does not enter the solenoid. When the points
from the battery through the start position on within the solenoid close the heavy pull in
the starter switch winding is shorted out. Thus the only current
HOLD-IN PULL-IN CONTROL SWITCH
in the solenoid during the starting period is in
WINDING

SOL ENOID

PLUNGER
WINDING

r) the fine hold-in winding.

When the engine begins to run and the starter
switch is released. several things happen
quickly First. current through the starter
switch to the solenoid is cut off. Then a strong
SHIFT LEvER
return spring pushes out the solenoid plunger.
breaking the circuit from the battery to the
starting motor and simultaneously pulling the
pinion out of mesh with the flywheel ring gear.
r- -t MOTOR
Ik TERMINAL
Series Parallel Switch
CONTACT DISK 1
Some heavy duty engines. especially diesels.
require a high voltage to start Cold weather
and other adverse starting conditions con-
OVERRUNNING JIL
CLUTCH
tribute to the need for the high starting
STARTING MOTOR voltage.
TO BATTERY

(8-81) SOLENOID CIRCUIT A high output starting motor on a 12-volt cir-

Courtesy 0 John Deere Ltd
cuit is adequate to start some large engines.
Other heavy duty engines. however. require
When the operator turns the starter switch. starting motors that will use two 12-volt bat-
current flows to the starter solenoid Since the teries for a total of 24 volts. By using a 24-volt
solenoid coils are wound in the same direc- battery supply. these high volt motors can
tion. current flows in the same direction. produce much greater starting speeds.
creating a strong magnetic field which pulls
the plunger into the field (Figure 8-82). The problem with this high voltage circuit is
that although the 24-volts is needed for start-
MAGNETIC FIELD
ing, 12-volts is adequate for electrical ac-
KEY SWITCH
cessories once the engine is going A series-
parallel switch solves this problem. When the
two batteries are needed for starting. they are
connected in series to deliver the 24-volts to
the starting motor. Once the engine is started
the circuit is connected in parallel so that only
one battery is used for normal electrical
operations

WINDINGS

(8-82) SOLENOID PLUNGER STARTING TO MOVE

AS STARTER SWITCH IS TURNED ON
Courtesy Of John Deere Ltd

155
 BASIC ELECTRICITY 8:53

(Figure 8-83) shows a series-parallel switch STARTING MOTOR DRIVES

for a 24-volt starting circuit.
After electrical power is trar -mitted from the
REGULATOR (12-vOLT1 battery through a switch to the starting motor.
I some type of connection IS needed to put this
GENERATOR
;12 VOLT) energy to work. The last link in the starting
TO L'GHTS
circuit is the starling motor drive. The drive
AND ACCESSORIES makes it possible to use the mechanical

.AMMETER
V energy produced by the starting motor.
The starting motor armature revolves at a high
12vOLT ;BOTH BATTERIES/ 12-VOLT speed to produce turning power. Since the
BATTERY % BATTERY turning speed required to start an engine is
STARTING s
A SWITCH s
comparatively slow, the starting motor is
Nos equipped with a small drive pinion which
meshes with the teeth of the flywheel ring
gear. The result IS a gear reduction with the
armature revolving as much as twenty times
SERI S PARALL for every revolution of the flywheel. Thus the
WITCH starting motor can develop high armature
speeds and considerable power while turning
FUSE
the engine over at a lower speed. When the
engine starts it speeds up immediately and
SOLENOID may soon reach 2000 RPM. Two thousand
SWITCH RPM's at the flywheel would mean twenty
AMMETER t24 VOLT, times that much at the starting motor pinion
BAT B1
Such a terrific speed would destroy the ar-
mature. and so a method is necessary to
demesh the pinion from the flywheel once the
STARTING MOTOR (24-vOLT! engine starts. Starter drives. therefore must
(8 -83) SERIES - PARALLEL SWITCH FOR 24 -VOLT have the capacity to both mesh and demesh
STARTING MOTOR OPERATION the pinion with the flywheel ring gear.
Courtesy of Jonn Deere Ltd
Types Of Starter Drives
Operation during starting is as follows There are many different starter drives, but
As the starting switch is closed. the solenoid they all can be classified under two basic
types according to the way they are engaged
coil within the series-parallel switch is
energized creating a magnetic force which at- 1 Inertia drive
tra:ts the senes-parallel switch plunger. The
plunger closes the two main switch terminals 2 Clutch dnve
and connects the two batteries tn series with
the starting motor Inertia Drives have a pinion gear that is
weighted on one side to aid In meshing and
At the same tome. the starling motor solenoid demeshing with the flywheel A Sendix drive
circuit is completed by a set of points is an example of an inertia drive.
mechanically closed by the series-parallel
switch plunger The battery-to-starting motor Clutch Drives are shifted into mesh by
circuit is completed and the starter turns over solenoid switches Two examples of clutch
After the engine IS started and the starting drives are Overrunning and Sprag clutch
switch IS released. the two batteries become drives Note that there is a direct relationship
connected in parallel when the series-parallel between starter drives and starter switches
switch goes into a neutral position This cir- Inertia drives use straight magnetic switches.
cuit permits operation of the machine's elec- while clutch drives use solenoid switches
trical equipment at a normal system voltage of which have a shifting mechanism
12-volts A more detailed description of the
series-parallel starter switch and circuit will
be given in future training

156
8:54 BASIC ELECTRICITY

inertia Drives When the pinion becomes fully meshed. its

forward motion stops. locking the pinion to
Bendix Drive the rotating armature shaft The heavy spring
cushions the shock to the armature shaft, as
The Bendix drive uses both the acceleration the shaft starts to turn the flywheel This
of the armature and centrifugal force acting spring also acts as a cushion when cranking
on the counter weighted pinion to move the the engine and when the engine backfires
pinion into mesh with the flywheel Before the
ignition switcn is turned on. the Bendix drive When the engine starts. the flywheel rotates
is out of mesh with the flywheel ring gear faster than the armature shaft. causing the
(Figure 8-84) pinion to turn in the opposite direction on the
screw and spin itself out of mesh (Figure 8-
ARMATURE SHAFT 86) Thus the engine is prevented from driving
the starting motor at an excessive speed.
DRIVE PINICN.
am
......
Lisiiro WM

Illr4= WitOrA
r,...--%.

0
/ )1)
., SLEEVE
44, /MO
BOO
SPRING
FLYWHEEL
X 2387 _
(8-84)
BENDIX Dr.iVE ENGAGING FLYWHEEL AS
ENGINE IS CRANKED X 2.389
ota,esv Jonn O4.. .1 e Lid
(8-86) BENDIX DRIVE PINION SPINNING OUT
When the starting switch is closed and the OF MESH AFTER ENGINE STARTS
battery voltage is fed to the motor. tne ar- tuutiesy of Jonn Deere Ltd
mature shalt accelerates rapidly The pinion When spun from the flywheel the centrifugal
gear, due to centrifugal force acting on the effect of the weight on one side of the pinion,
counter-weight, runs forward on the revolving holds the pinion to the sleeve in an in-
screw sleeve until d meets or meshes with the termediate position until the starling switch Is
flywheel gear (Figure 8-85). opened and the motor armature comes to rest.
As long as the operator keeps the starting
motor switched on with the engine running.
the starting motor will free speed in the in-
_ ANION termediate position This free speeding is not
good for the armature and is the reason that
the starter switch should be released Im-
mediately after the engine has started
Certain precautions must be observed in
operating a Bendix-type starting motor If the
engine backfires with the pinion meshed with
the engine flywheel, and the starting motor is
'v; SPRING operating, a terrific stress is placed on the
ki.f188 parts The stress occurs because the motor
armature attempts to spin the drive pinion rn
(8-85) BENDix DRIVE PINION FULLY MESHED one direction while the engine. having back-
uuriesy 0, John Demo Ltd fired. turns the drive pinion in the opposite
direction This clash cf opposing forces
sometimes breaks or wraps up the Bendix
spring
Engine ignit nn timing should be checked and
corrected to overcome backfiring
157
 BASIC ELECTRICITY 8:55

Another problem with a Bendix drive can oc- Clutch Drives

cur during repeated attempts to start an
engine When the engine is coming to rest it Overrunning Clutch Drive
often rocks back. or rotates in reverse. for part
of a revolution If the operator attempts to re- The overrunning clutch drive (Figure 8-88) is
engage the drive pinion at the instant the one of the most widely used drive
engine is rocking back. the drive housing or mechanisms; it meshes and demeshes the
the Bendix spring may be damaged. drive pinion with the flywheel
To prevent such damage. the operator should The overrunning clutch uses a shift lever to
always wait at least live seconds between at- actuate the drive pinion The pinion. together
tempts to crank so that the engine stops turn- with the overrunning clutch mechanism, is
ing moved endwise along the armature shaft and
into. or out of. mesh with the flywheel. The
Variations in Bendix Drives shift lever may be operated either manually or
by a solenoid.
1 The foto -thru starter drive (Figure 8-F7)
incorporates some designs into the stan-
dard Bendix di we that overcome the
problems with the Bendix mentioned
above A folo-thru has a detent pin which SHIFT
locks the drive in the cranking position to LEVER
prevent disengagement on false starts.
This pin is thrown out by centrifugal force PINION
when the engine runs and the pinion then STOP
disengages

DRIVE SPRING DENTIL CLUTCH

yor
41_4 1"
, 11

ZM OVERRUNNING
CLUTCH
SCREWSHAFT PINION AND (8-88)
ANCHOR PLATE BARREL Courtesy 01 Joni Deere Lid
DRIVE HEAD
(8-87)
courtesy of Deice Division of
General Motors Corporation Operation of the overriding clutch is as
follows
Another protective feature of the Polo -thru
drive is the dentil clutch. a precision made The drive pinion in its neutral position is out
one way clutch which drives in one direc- of mesh and separated from the flywheel ring
tion and slips in the other Since the shaft gear When the starting switch is closed.
will slip in the non drive direction. the current flows to the solenoid. closing the
starting motor is protected Irom engine switch circuit As the solenoid switch closes.
backfire the shift lever moves the pinion into mesh and
then completes the circuit to the starting
The folo-thru is the most common type of motor. If the pinion and the flywheel teeth
inertia drive used today. meet instead of meshing. the spring-loaded
pinion rotates the width of one-half tooth and
2 Some heavy-duty cranking motors use a drops into mesh as the armature starts to
friction-clutch Bendix drive. This type of rotate
drive functions in much the same manner
as other Bendix drives. However. it uses a When the armature shaft rotates during
series of spring-loaded clutch plates. in- cranking. small rollers in the clutch become
stead of a drive spring. that slip momen- wedged aga,st the shift collar attached to
tarily during engagement to relieve shock. the pinion. This wedging action locks the

158
2

8:56 BASIC ELECTRICITY

pinion gear to the clutclp which is splined to Sprag Clutch Drive

tne armature shalt. and causes the pinion to
rotate with the shaft (Figure 8-89). The Sprag Clutch Drive (Figures 8-90 and 8-
9 r) is used primarily on larger starting motors
to carry the high torque required to turn over
ARMATURE high-compression engines. The Sprag Clutch
SHAFT
Drive is constructed and operates like the
Overrunning Clutch Drive. except that a series
of sprags replace the rollers in the clutch
assembly.

The Sprag Clutch Drive operates as follows:

Movement of the shift lever against the collar
PINION GEAR
causes the entire clutch assembly to move
along the splined shaft until the pinion teeth
engage the flywheel ring gear. If the teeth
ROLLERS
meet instead of meshing, continued
COLLAR movement of the shell and spiral splined
(8-89) sleeve causes the pinion to rotate and clear
OVERRUNN11%3 CLUTCH ORP, E ENGAGED the teeth. The compressed meshing spring
Jvfin opese Lid then forces the pinion into mesh with the ring
gear If the pinion does not clear before the
Wher, the engine starts. the flywheel spin:. the two retainer cups meet. shift lever movement
pii ion gear faster than the armature. is stopped by the retainer cups and the
re'easing the rollers ar,c1 unlocking the pinion operator must start the engagement cycle
liorn Ulf armature. releaspng the rollers and over again. The shift lever stopping prevents
unlocking the pinion from the armature shaft closure of the switch contacts to the motor
The unlocked pinion still meshed with the with the pinion not engaged. On the second
flywheel. rt,nS at flywheel speed (overruns) attempt. the pinion will engage in a normal
safety anc, freely until the switch is opened manner.
and the shift lever pulls the pinion out of PINION
mesh This fea:ure prevents the armature from
being driven at excessive speed by tne
engine

SPRAGS

SHIFT COLLAR
(8-91) Y
SHOULDER (8-90)
BAFFLE RETAINER
CUPS SPRAG CLUTCH DRIVE
CUPPED PINION
STOP Courtesy of John Deere Ltd

SPRING SPLIT WASHER

PINION
COLLAR. SLEEVE .O
AND SHELL ASSEMBLY DISASSEMBLED VIEW OF LATE TYPE
HEAVY OUTY SPRAG CLUTCH
Courtesy of Delco Onns:on of DRIVE ASSEMBLY
General Motors Corporation

159
-
 BASIC ELECTRICITY 8:57

With the pinion engaged and the switch

closed. torque is transmitted to the pinion
through the sprags. The sprags tilt slightly
and are wedged between the shell and sleeve.
When the engine starts. the ring gear drives
the clutch faster than the armature. and the
sprags tilt in the opposite direction freeing tile
sleeve and pinion and allowing them to
overrun the shell and armature. When the
switch is openea the shift lever pulls the
pinion out of mesh To avoid prolonged
overrunning, the starting switch should be
opened as soon as the engine starts.

REMOVING AND INSTALLING STARTERS

When removing and installing starter motors.
the following precaution and good work prac-
tices should be followed'
I First. remove the ground strap from the
battery Then install a 00 NOT OPERATE
TAG on the controls.
2 Tao all wires before disconnecting them.
Pieces of masking tape work well for
tagging
3 Starter motors. especially large ones. are
wavy, so be sure to support a motor when
removing Ins flange bolls
4 Check tne flywheel ring gear condition
before reinstalling the starter motor. If it is
badly worn or damaged. the ring gear
snout(' be repaired
5 Wnen installing the motor be sure to
tighten the flange bolts evenly

160
 8:58 BASIC ELECTRICITY

QUESTIONS STARTER MOTOR 7 List the two basic functions of the starter
drive
1 The starting circuit converts electrical
energy of the battery into 8 What is the first step before attempting to
.._ _ __. _. _______ _ to crank the engine' remove a starter motor?
(a) kinetic energy (a) lack the vehicle up
(b) hydraulic energy (b) check the ring gear condition
(c) pneumatic energy (c) remove the battery ground strap
(d) mechanical energy (d) remove the fan belt
2 True or False A starting motor is 9 Why is the drive pinion center weighted
designed to operate for short intervals on an inertia drive such as a Bendix?
under great overload.
10 An overrunning clutch mechanism allows
3 The principle of an electric motor is that a clutch drive pinion to safely _____ --
a current carrying conductor is placed in the starter motor armature shalt when the
a magnetic held and the interaction be- engine starts
tween the two fields causes:
11 There is a direct relationship between
... (a) currenl to flow in the field winding starter drives and starter switches. Iner-
(b) a fo -..'e to be exerted on the con- tia drives use ___ _ _____ switches.
ductor Clutch drives use .____ - switches.
(c) current to stop flowing in the con-
ductor
(d) an equal force on the conductor
4. The operation of magnetic, solenoid and
series-parallel starter switches depends
on:

friction and magnetism

(a)
(b) a core tightly wrapped around a coil
(c) movement of a magnetized core into
and out of an electromagnetic coil
(d) two bar magnets applying a force to
each other
5. What is the main difference between a
magnetic starter switch and a solenoid
starter switch?
6 A series-parallel switch is used to
(a) connect two batteries in series for
starting and in parallel for charging
OA connects four batteries in parallel
for starting and returns two of them
to series for charging and ac-
cessory loads
(cl keeps the starter from overloading
the batteries
(d) connects two batteries in parallel
for starling and in series for
charg in g

161
 BASIC ELECTRICITY 8:59

CHARGING CIRCUITS IGNITION SWITCH

A charging circuit does two lobs:

recharges the battery
-- generates current to operate electrical REGULATOR
ac eessori es

There are two kinds of charging circuits'

AMMETER
DC charging crcuits (use generators) ALTERNATOR
AC charging circuits (use alternators)

DC Charging Circuits have a generator and GROUND

regulator (Figure 8 -92).

REGULATOR
BATTERY

flaN))i 111114 (6-93) AC CHARGING CIRCUIT

VIP Courtesy of John Deere lid
g
AMMETER GENERATOR
An alternator is similar to a generator in that it
produces AC current, but it differs in the way
it changes AC to DC. Alternators use an elec-
tronic device called a diode rather than
GROUND
brushes and a commutator to change the AC
to DC.
The function of a regulator in an AC charging
BATTERY circuit is to prevent overcharging of the bat-
(8-92) tery and to limit the alternator's voltage output
DC CHARGING CIRCUIT to a safe amount. Many modern regulators are
Courtesy of John Deere Ltd made with transistors and are referred to as
solid state.
Driven by the engine, the generator makes OPERATION OF A CHARGING CIRCUIT
electrical power :n the form of alternating
current (current that moves in one direction, All charging circuits operate in three stages'
and then in the other) Through the use of a
commutator and brushes. the generator 1. During starting the battery supplies all the
changes the alternating current (AC) into current.
direct current or DC which moves in one 2. During peak operation the battery helps
direction only. the generator supply current.
The regulator does the following three ,obs" 3 During normal operation the generator
1 Opens and closes the charging circuit be- supplies all current and recharges the bat-
tween the battery and generator. tery

2 Prevents overcharging of the battery. In both AC and DC charting circuits, the bat-
tery starts the circuit when it supplies the
3 Limits the generator's output to a safe current to start the engine The engine then
amount. drives the generator (or alternator) which
produces current to take over the operation of
AC charging circuits have an alternator and a the ignition, lights and other electrical ac-
regulator (Figure 8 -93). cessories. The battery will help out during
peak operation when the electrical loads aie
too much for the generator (or alternator)

162
 8:60 BASIC ELECTRICITY

The three stages of the charging circuit are operation and function. A starting motor uses
illustrated in Figure 8-94 current to turn its armature and shaft and its
function is to produce working power. A
generator uses engine power to turn its ar-
mature and its function is to produce elec-
tricity. Figure 8-95 illustrates the parts of a
basic generator. (Note that an actual
generator has not one but many loops.)

POLES

FIELD
WINDINGS
BATTERY SUPPLYING
LOAD CURRENT

FIELD
WINDINGS
s

BATTERY CURRENT PRODUCED BY

ELECTROMAGNETIC
INDUCTION
X u.s7 (8-95)
COMPLETE PARTS OF BASIC GENERATORS
GENERATOR AND BATTERY Courtesy of John Deere Lid
SUPPLYING LOAD CURRENT
The earlier discussion of electromagnetism
showed that when a conductor was moved
through a magnetic field. a current was in-
duced in the conductor. The direction of in-
duced current depended on the direction in
which the conductor passed through the field.
Generators use this principle of elec-
tromagnetic induction to produce current.
Looking at the illustration of the basic
generator in Figure 8-96. consider the clock-
wise rotation of the loop through the magnetic
field During the first half of the revolution
(Figure 8-96f the top of Side A cuts through
GENERATOR SUPPLYING LOAD the magnetic field first. whereas the bottom of
CURRENT AND CHARGING BATTERY side 8 is first to cut the field. In this half of the
(8-94) revolution. then. the loop has current induced
Courtesy of John Deere Ltd in it that travels away from Side B towards
Side A. During the second half of the
revolution. the field cutting is reversed. The
DC CIRCUITS top of Side 8 is the leading edge. while the
bottom of Side A is leading. Thus the current
GENERATORS flows in the opposite direction. away from
The make-up of a basic generator is stmilar to Side A towards Side B The result is alter-
that of the basic starting motor previously nating current
described. Both have an armature. poles. a
field winding. brushes and a commutator.
However. there is a major difference in their
163
 BASIC ELECTRICITY 8:61

4 And so it goes, the amount of current

spiralling upwards.
Ifthis increase in current went unchecked.
the generator would burn up Thus. the need
for a regulator The regulator controls the
amount of current and voltage the generator
can produce. Besides having current and
voltage limiters. the regulator has a cutout
FIRST HALF OF SECOND HALF OF relay that closes the circuit between the
REVOLUTION REVOLUTION generator and the battery when the generator
(8-96) is running and opens it when the generator is
stopped. This relay allows the generator to
The generator must convert this AC to DC. charge the battery. but does not allow the bat-
The commutator and brushes perform the tery to discharge through the generator when
conversion. The brushes slide on. or brush. the generator is not running.
the commutator ring. Since the ring is split the
brush on the left side is always in contact with AC CIRCUITS
the side of the loop that is pushing up through Alternators
the magnetic field. and the brush on the right
side is always in contact with the *I de of the The alternator (also called an AC generator)
loop that is going down through the field. is the heart of the AC changing circuit. Alter-
Thus the current always flows in the same nators are generally more compact than
direction generators and can supply a higher current at
low engine speeds. Since in recent years
Three factors will affect the induced current there has been an increase in the use of elec
that an actual generator produces trical accessories at low or idle engine
1 The strength of the magnetic held. speeds. alternators are more common today
than generators
2 The number of wire conductors on the ar-
mature (i e . the number of loops) Basic Operation Of An Alternator
3 The speed of the armature. Whereas a generator induces current by
moving a conductor through a stationary field.
Note here. as was mentioned earlier. that the an alternator induces a current by doing the
more current a generator (or an alternator) opposite. by moving the field across a
produces. the more resistance there is against stationary conductor.
the armature Thus. the more current you draw
from a generator or alternator. the harder it is A basic alternator can be made by rotating a
to turn. This IS the reason that drive belts for bar magnet inside a single loop of wire As WS
generators and alternators must have the rotated current is I duced in the wire (Figure
proper tension so that they don't slip during 8-97)
peak demands

Need To Regulate The Generator

Looking at the diagram of a basic generator.
you can see that current produced by the
generator is also used to supply its own field
circuit. Such an arang -lent causes a
spiralling increase in the amount of current
produced The reason is as follows-
1 The more current the armature produces.
the more current is sent to the field circuit ROTATING
LOAD MAGNETIC
2 With this additional current. the magnetic CIRCUIT FIELD
field becomes stronger
(8-97)
3 With a stronger magnetic field, more
current is induced in the armature courtesy of Jonn Deese Ltd

164
8:62 BASIC ELECTRICITY

If the magnet is rotated the other way. the

current will flow in the opposite direction The
faster the magnet is turned the more current is
induced
However, an alternator made with a bar
magnet rotating inside a single loop of wire is
not practical because very little voltage and
current are produced Air is not a good trans-
mitter of magnetism. and only a few lines of
force will come out of the North pole and en-
ter the South pole Production of current is im-
proved when the loop of wire and the magnet
are placed inside an iron frame (Figure 8-98).
The iron frame provides a form to which the SLIP RINGS
loop of wire can be attached It also acts as a
conducting path for the magnetic lines of (8-99)
force. greatly increasing the number of lines ROTOR
of force between the N and S poles. With the Courtesy of Delco-Remy
increased lines of force comes more induced Dryisron of General Motors Corporation
voltage. and thus a more useful alternator
STRONG FIELD
WEAK FIELD

ROTOR

IIP\CONDUCIOR
AIR PATHHIGH IRON FRAMEL OW
RELUCTANCE RELUCTANCE
.seJld
MAGNETIC LINES OF FORCE
Courtesy of John Deere Ltd

In an alternator the rot-- tagnet is called

the rotor. and the loop and outside frank. (8-99) STATOR
assembly is called the stator. A rotor and a Courtesy 01 Delco-fierily Division of
stator from an actual alternator are shown in General Motors Corporation
Figure 8-9t, Note that the stator has not one
but many loops of wire wound in three The current induced in the stator by the rotor
separate :oils. Also note that the rotor is not a is alternating current and it must be changed
bar maprietic but pole pie :es and an elec. to AC before it can be used by the electrical
troma;netic held winding. The rotor is driven accessories An alternator uses diodes to
by the engine and the field winding is sup- change the AC current to DC A diode is an
plied current from the battery. electronic device that will allow electricity to
flow through it in one direction but not in the
other The discussion here won't go into why
the diode allows passage of electricity one
way but not the other: this information can be
found in any modern book on electricity. In
electrical diagrams the symbol for a diode is,
OF. which means that current can
flow through the arrow but not through the

165
 BASIC ELECTRICITY 8:63

vertical line. Without going into detail, the slates of charae and the demands of the elec-
diodes are located in circuits such that they trical system (up to, of course. the alternator's
send the alternating current received from the limitations).
three stator coils all in ths same direction
resulting in a DC current. To understand how There are many variations of alternator and
diodes work follow the path of the current generator regulators and these will be
through the six diodes in Figure 8-100. discussed in later courses.
Remember that the current can only flow in
the direction of the arrow through the diode.
1. From coil A through coil B and C and
back to A again
2. From B through A and C and back to B
again
3 From C through A and B and back to C
again

FIELD
TERMINAL

RECTIFIER DIODES

BATTERY
(8-100)
Courtesy 01 Jonn Deere Ltd

Need To Regulate The Alternator

Alternators like generators must have
regulation. The type of regulation, however, is
different in the two systems. Generators. as
you will recall, required a cutout between the
battery and generator. in addition to current
and voltage limiters. Since alternators use
diodes. they don't need a cutout (i.e.. current
can only go from the alternator to the battery.
it can't go the other way). Nor do they need a
current limiter because the coils are con-
structed so that the current they produce is
sell limiting What regulation alternators do
need. though, IS a voltage limiter. Voltage out-
put is controlled by limiting the amount of
current in the field circuit. By limiting the
voltage output of the alternator, the amount of
current produced IS in correct proportion to
both the demands of the battery in its various

166
8:64 BASIC ELECTRICITY

PREVENTIVE MAINTENANCE SERVICE OF

CHARGING SYSTEMS
Removing and installing generators and alter-
nators is a fairly straight forward job.
However, there are a few suggestions that will
help you do a better. safer job:
I First, remove the ground strap from the
battery.
2 Wrien multiple wires are used on the
generator, tag the wires as they are
disconnected
3. On some vehicles. several accessories
may be driven from a multiple groove
crankshaft pulley, and to replace any of
the inside drive belts you will have to
remove all the outs;de belts first. Also. on
vehicles where special equipment has
been installed or accessories relocated, it
may be necessary to remove these items
before you can replace a drive belt.
4 Generators. especially large ones. are
heavy; support a generator when
removing the mounting bolts.
5 Check the condition of the drive belt and
its sheaves and :heck the sheave align-
ment (see the section on belt maintenance
in Block 7. Engines).
6 When installing generators. position them
so that the spacers are in the right
location.
7 Check belt tension using a belt tension
gauge or the belt depression method (see
"Engines"). The most common charging
system problems are caused by worn or
improperly adjusted drive belts. Preven-
tive maintenance on generators stresses,
therefore. that belts be checked regularly
for alignment and tension.

167
 BASIC ELECTRICITY 8:65

QUESTIONS CHARGING SYSTEMS

1. During normal engine operation the
generator or alternator:
(a) helps the battery supply current
(b) supplies all current
(c) recharges the battery
(d) both (5) and (c)
2. A generator changes the alternating
current it produces to direct current by
the use of:
(a) an accumulator and brushes
(b) a commutator and windings
(c) a commutator and brushes
(d) an accumulator and diodes
3 List the three jobs the regulator must do
in a DC charging system.
4. An alternator changes AC to DC by the
use of:
(a) resistors
(o) transistors
(c) diodes
(d) thermistors
5. A regulator on an AC charging system
has one job to do:
(a) Omit the voltage to a safe value
(b) limits the current to a safe value
(c) opens and closes the charging cir-
cuit
(d) control alternator speed to control
current output
6 Briefly explain the difference in the way
that current is induced in a generator
and in an alternator
7 True or Fr.P.ze? The most common
charging system problems are caused by
worn or imprope.iy adjusted drive belts.

168
41.
8:66 BASIC ELECTRICITY

IGNITION SYSTEM
The purpose of the ignition system is to take
the low voltage of the battery and create high SPARK
voltage at the spark plugs to fire the engine. PLUGS
This purpose is accomplished by means of an
induction coil. points and a condenser. The ego

OISTRIBUTOR
ignition system must deliver the high voltage
to the right spark plug at the right time in or-
der to get maximum power from combustion.
The ignition circuit has two separate circuits
(Figure 8-101)
Primary low-voltage circuit
Secondary high-voltage circuit CONDENSOR

IGNITION SWITCH
The Primary Circuit is the oath for low-voltage
current from the battery <11

It includes these parts'

1 Ignition Switch
2 Coil Primary Winding BATTERY =in PRImARYCIRCUiT
3 Distributor Contact Points 1=I SECONDARY CIRCUIT
4 Condenser X336-5 (8-101) MAGNETIC FIELD
IGNITION CIRCUIT (BYPASS TYPE SHOWN)
Tne Secondary Circuit is the high voltage Courtesy of John Deere Ltd
path for current stepped up by the coil It in-
cludes these parts IGNITION CIRCUIT OPERATION
The ignition circuit can be naturally separated
1 Coil Secondary Winding into (1) the operations before the distributor
2 Distributor Rotor points open and (2) the operations after they
open.
3 Distributor Cap and Secondary Winding Operation Before The Distributor Points
4 Spark Plugs Open
Before the engine is started. the distributor
points are closed (Figure 8-102)
1\
DISTRIBUTOR PRIMARY PRIMARY
CAP TERMINAL TERMINAL

CONTACT
ROTOR POINTS
(CLOSED)

SPARK
PLUGS

PRIMARY
WINDING

BREAKER
CAM
COIL
(8-102)
CONDE.ISER DISTRIBUTOR OPERATION BEFORE THE DISTRIBUTOR
POINTS OPEN
GotaloSy nl Joni) 1)etfo Ltd

169
 BASIC ELECTRICITY 8:67

When the ignition switch is turned on. current The surge of induced voltage in the primary
flows from the battery into the primary win- winding is absorbed by the condenser The
dings of the coil, as shown in dark lines. From surge of induced voltage in the secondary
tne primary winding the current at low winding which. 'or reasons that will be ex-
vultage simply travels through the closed plained later. is much higher. travels to the
distributor points and back to ground The distributor cap. The rotor inside the distributor
current creates a magnetic, field around the cap turns to a spark plug terminal and directs
plummy winding and since the secondary the voltage surge to the correct plug through
wiring is wound underneath the primary. the insulated cables. At the spark plug, high
;,econdary. too. nas ,:: magnetic field around it voltage current flows down the center wire or
electrode and on reaching the tip jumps the
Operation After The Distributor Points Open gap to the plug's ground electrode As the
current jumps it creates a spark.
As the engine rotates in starting. it drives the
distributor shalt and the breaker cam. The The complete cycle of current coming into the
breaker cam opens the distributor points. and primary winding, stopping. and induced
the second phase of ignition Degins as current travelling from the secondary winding
illustrated in Figure 8-103 to the distributor cap and spark plugs hap-

SPARK
PLUG "...-
TERMINAL DISTRIBUTOR
CAP SECONDARY
WINDING

CONTACT
ROTOR POINTS
SPARK (OPEN)
PLUGS

BREAKER
CAM

COIL

(8_103) CONDENSER DISTRIBUTOR

OPERATION AFTER THE DISTRIBUTOR pens 'rpm 100 to 300 times a second depen-
POINTS OPEN ding on the speed of the engine.
, , ,,t jrrin Opere Ltd
One other point must be made about the
ignition circuit as a whole. Going back to the
first diagram in this section, notice the
As the points open. the flow of current in the
resistor on the primary circuit and also note
primary circuit is stopped instantly StDpping
the dotted line that bypasses this resistor.
this current collapses the magnetic field that Such an arrangement is called a bypass
has built up around the two windings Collaps- ignition system. When the ignition key is turn-
ing the field induces a current (discussed ed on. full battery voltage 'lows through the
more fully below) in the two coils. since there
dotted red line. resulting in a hotter spark for
is a magnetic field moving across a con- first ignition. When the ignition switch is
ductor You remember the. if a conductor is released. primary current flows through the
moved through a magnetic field (the principle solid line and resistor to the coil. In a 12-volt
of a generator) or vice versa if the magnetic system. the resistor reduces voltage by half
field is moved across the conductor (the prin- and allows the use of a 6-volt coil The smaller
ciple of the alternator) a current is induced in coil gives longer to the distributor points.
the conductor condenser. and coil because it creates less
heat.

170

t
8:68 BASIC ELECTRICITY

Having seen how current flows in an ignition The coil performs the key function in the
system the individual parts of the system will ignition circuit, it steps up battery voltage
be discussed from 6 or 12-volts to 15 to 20 thousand volts.
enabling a spark to occur at the spark plug.
Wiring In The Primary Circuit
Primary wiring is low voltage wiring. 16 or 18 Coil Operation
gauge plastic insulated. stranded copper wire. Keep in mind the electromagnetic principle of
that carries current at battery voltage through the coil. when a magnetic held crosses over a
the primary ignition circuit The connectors at conductor a voltage is trieJced in that con-
the ends of the wire are usually crimped or ductor. The faster the field travels and the
soldered on more conductors there are. the greater the in-
duced voltage.
Ignition Coil and Condenser
1 Current at battery voltage travels to the
The center of the coil (Figure 8-104) is a soft primary winding in the coil. As current
iron core The secondary winding of fine wire begins to come into the primary winding, a
is wrapped around this core. One end of the magnetic field starts to build around it.
secondary winding is connected to the high- and since the secondary winding is wrap-
tension terminal. the other end to the primary ped underneath the primary the same
winding magnetic field crosses over to the secon-
SEALING NIPPLE dary winding. As the field builds up. some
HIGH TENSION voltage is induced in the secondary win-
TERMINAL ding but not enough to send a spark
COIL CAP across the gap at the spark plug.
PRIMARY
TERMINAL 2 This greater voltage that produces the
spark is induced as follows The contact
pnints are opened and current is im-
SECONDARY mediately cut off to the primary coil. Cut-
WINDING
ting off the current causes the field to
collapse very quickly. and thus the field
PRIMARY travels back over the secondary windings
MOOING much faster than it came across. (Note
IRON
that the electromagnetic field doesn't just
CORE disappear when current is cut off: it must
LAMINATION
collapse or fall dawn much like. a brick
building would : The fast collapsing field
PORCELAIN crossing back over the many loops in the
INSULATOR
secondary winding induces a very high
(8-104) IGNITION COIL voltage that sends a surge of current up to
Courtesy 01 Jonn Deere Ltd a spark plug to jump the gap and cause
The primary winding of heavy wire is wrapped the spark needed for ignition of the fuel.
around the secondary winding. There are ap-
"4 While the high voltage is being induced in
proximately 100 times less primary loops than
the secondary winding. what is happening
secondary ones. The two ends of the primary
winding are attached to the primary terminals
in the primary winding? As the field
collapses. a voltage is self-induced in the
in the coil cap. One of these terminals is con-
primary winding as well as the secondary.
nected to the power source. the other is con-
nected to the distributor points. However. the voltage is much less than
that of the secondary because the primary
\ shell of laminated material is placed around has approximately 100 times fewer loops.
the windings and core as shown. The core. The self-induced voltage in the primary
windings. and shell are then encased in a
metal container. The container is filled with winding tries to push a spark across the
either oil or insulating material and sealed points in an attempt to keep the current
flowing And there is enough induced
with the coil cap The cap is made of a shaped
insulating material with the two primary ter- voltage to send a spark across when the
minals and one high-tension terminal molded
points first start to open and are not very
far apart Such a spark would damage the
into it.
171
 BASIC ELECTRICITY 8:69

points and decrease the rate of held HIGH-TENSION

TERMINAL
collapse. To prevent sparks at the points a COIL
PRIMARY
condenser is used. TERMINAL
PRIMARY
The condenser IS connected across the TERMINAL
points as illustrated in Figure 8-105.
DISTRIBUTOR
TO IGNITION
FOIL SWITCH

1;7
A,

DISTRIBUTOR
PRIMARY
TERMINAL

INSULATION
1111 NEGATIVE-GROUND SYSTEMS
Courtesy og Jonn Deere Ltd
CONDENSER POSITIVE-GROUND SYSTEMS
(8-106)
(8-105)
CORRECT POLARITY OF THE COIL
Instead of the induced voltage pushing Co, -esy ct JOnn Deere 110
current across the points. the current is
sent into the condenser. The condenser in On negative-ground systems. the negative
effect catches the induced voltage from primary terminal is connected to the
the primary winding. The condenser is distributor.
soon full or cnarged up and the voltage es
ready to try again to push the spark On positive-ground systems. the positive
primary terminal is connected to the
across the points. but by this time the distributor.
r,oints are open too wide for a spark to be
pushed across The delaying tactics of the Most coils have the polarity signs imprinted in
condenser prevent current from crossing the cap by each terminal.
the points and in so doing allow the field
in the coil to continue to collapse.
IGNITION DISTRIBUTOR
rt should be pointed out that contrary to
what was said above sparking is not 100% The distributor does three lobs. It.
eliminated from the points. During the first
millionth of a second that the points opens and closes the primary circuit
separate. there is a very small spark times the high voltage surges
produced across the points. It is this small
delivers current to the spark plugs
spark that accounts for some pitting and
wear on the points. Distributor Parts Can Be Put Into Three
Groups
Set vice Note On The Polarity Of The Coil
Whenever the primary leads are disconnected Primary Circuit
from the coil. observe the correct polarity Operation Timing Delivery
when reconnecting them. Wrong polarity of drive shaft drive shaft drive shaft
the coil IS not a serious problem. but can breaker cam breaker cam rotor
cautae damage over a long period of time. A breaker plate centrifugal cap
coil that is incorrectly connected to the power advance
source and the distributor will require an extra contact points contact points
4000 to 8000 volts to create the spark
Misfiring can result as the voltage required to
rump the spark gap increases. Figure 6-106
illustrates proper coil connections.

172
 8:70 BASIC ELECTRICITY

Operation Of The Distributor The primary circuit is again complete and

current flows until the next lobe opens the
As the distributor drive shaft turns. a cam lobe paints. The cycle then repeats itself.
pushes the breaker lever tubbing block. This
action opens the contact points. stopping the In this way a spark is created as each lobe of
current flow in the coil's primary circuit the cam opens the contact points. The com-
(Figure 8-107) plete cycle for each spark takes place at a
very high speed. A typical distributor is shown
in Figure 8-109.

POINTS ROTOR
OPEN
PLUG ROTOR

CAM
BREAKER
LEVER
CONDENSER

CAM LOBES COIL

BREAKER
RUBBING BLOCK
DISTRIBUTOR PLATE

(8.107)
Courtesy 01 John Deere Ltd HOUSING

The collapsing field and the resulting high- ADVANCE

voltage surge an the coil's secondary winding DRIVE
SHAFT MECHANISM
forces current into the center terminal of the
distributor cap. The distributor rotor receives
this current and delivers it to the proper spark
plug to fire the engine
(8-109) CUTAWAY OF DISTRIBUTOR
Meanwhile. the distributor cam lobe has Courtesy of Jonn Deere Ltd
moved away from the rubbing olock and
spring tension brings the points back into Distributor Parts
contact (Figure 8-108)
Drive Shaft is driven at one-half engine or
crankshaft speed by the engine camshaft. It
drives the centrifugal advance mechanism
(described later). the breaker cam. and the
rotor.
Breaker Cam is slip-mounted on the drive
POINTS shaft and pinned to the centrifugal advance.
CLOSED The cam has one lobe for each engine cylin-
der.
Breaker Plate Is a mounting for the contact
points and condenser It also has a terminal
which connects the points and condenser to
the primary circuit -
COIL
Contact Points Assembly consists of two
contact points. a breaker lever and a breaker
DISTRIBUTOR lever spring All three are mounted on a base
(8-108) which is attached to the breaker plate. The
two points are usually made of tungsten. One
Courtesy of John Deere Ltd
is foxed to the base. the other is attached to
the breaker lever and aligned with the first.

173
0

BASIC ELECTRICITY 8:71

The breaker lever is mounted on a pivot pin to the piston will be at its optimum 12° position
the assembly base The lever is made of metal at combustion (Figure 8-1t1) II the engine
and has a nylon or bakelite rubbing block speed is doubled to 2000 RPM. the distance
The breaker lever spring 6s attached to the the piston would travel is also doubled to 32
breaker lever The spririg holds the lever to degrees. and the spark. therefore. must occur
the cam after each cam lobe passes the rub- at 20 degrees before top dead center to give
bing b:,ck maximum power to the piston (Figure 8.111).
Rotor is mounted on the upper part of the
breaker cam A flat side of the rotor hub fits
on a flat side of the cam In this way the rotor
will fit in only one position. On the top of the 12
SPARK 12
rotor. a spring metal piece is in contact with 1 PAST
SPARK
PAST
the center terminal of the distributor cap A BEFORE TOC BEFORE
TDC
rigid piece completes the circuit to each T C TO C
spark plug terminal in the cap as the rotor
turns. The rotor itself is molded of a plastic
material which makes it a good insulator.
Distributor Cap is also molded of a plastic
AT 1,000 ENGINE RPM AT 2,060 ENGINE RPM
material Brass or copper contact inserts are
embedded in the cap. These contacts are SPARK TIMING OF TilE ENGINE COMBUSTION
equally spaced around the cap and lead to the (8.111)
spark plug terminals in the top of the cap. The coliesesy .11 Jonn Deere Ltd
cap is notched into the housing to prevent in-
correct installation. It has been shown that spark timing must be
adjusted to engine speed. The advance
CENTRIFUGAL ADVANCE MECHANISM mechanism makes this adjustment. The most
popular type of advance mechanism is a cen-
An advance mechanism it a device which trifugal advance. its main parts are two
takes engine speed into account and times weights. a weight base and two springs
the spark to occur while the piston is in its (Figure 8.112).
best position to be driven by the expanding
gases For the purpose of discussion, assume CENTRIFUGAL ADVANCE MECHANISM
that the engine piston must be at 12° past top
dead center for full combustion force (Figure ADVANCE
8-110). The 12° past top center stays the same EIGHT
regardless o' the engine speed.
CAM
WEIGHT
BASE
PIN
120
CONNECTING
PAST
T0C
WEIGHT
SPRING
PRIMARY
LEAD
IDLE (8-112) Courtesy of Jonn Deere Ltd

(8.110)
Cuortesy of Jonn Deere Ltd e weight base is part of the distributor drive
shaft. The springs are connected to the base.
AsSiime also that it takes 0 002 seconds to while the weights are placed on the base. The
reach the full force of combustion. and that at distributor breaker cam has two pins which
1000 revolut.ons-per-minute (RPM) the piston connect it to the springs and weights.
will travel 16 degrees during this time. The
spark at this speed. therefore. must come at
four degrees before top dead center so that

174
 8:72 BASIC ELECTRICITY

At idle speed the breaker cam is pinned to the

base and rotates with the drive shaft. The cam
lobes then open the points at a preset time
such as four degrees before top dead center.

NO ADVANCE FULL ADVANCE

(8-114) VACUUM ADVANCE MECHANISM
OPERATION OF CENTRIFUGAL ADVANCE Courtesy of Jonn Deere Ltd

(8-113) Courtesy of Jonn Deere Ltd The vacuum advance uses an air-tight
As tree engine speeds up, centrifugal force diaphragm connected to an opening in the
throws ,he weights out against spring tension carburetor by a vacuum passage. The
'Figure 8-113) When tha weights move out diaphragm is connected by linkage to the
they twist the breaker Jarn so that the cam distributor housing or the Vreascer plate.
lobes strike the breaks+ lever earlier Thus the When a vacuum at the intake manifold draws
contact points open earlier and the spark is air from the diaphragm chamber. it causes the
advanced As the engine slows down. the diaphragm to rotate the distributor breaker
springs grsdually return the breaker cam and plate in the opposite direction of drive shaft
weights to their original position rotation. The breaker lever contacts the
The centrifugal advance is calculated in a set breaker cam lobes sooner and advances the
ratio et spark advance to engine speed: at full spark.
throttle it gives complete spark advance A combination of the centrifugal and the
Cylinder conditions, however, are not as vacuum advance mechanisms gives a spark
regular as the set advance-speed ratio might advance unit which is sensitive to all speed
imply There is a lime, at part throttle for and load conditions.
example. when the cond:tior,s during com-
pression and combustion are such that more Other parts of the ignition system yet to be
1 spark advance could be used. At part throttle discussed are secondary wiring, a ballast
the amount of air taken into the engine is resistor, and spark plugs.
restricted and a vacuum can develop in the
engine inta. e manifold, allowing less fuel and SECONDARY WIRING
air into the cylinder The amount of vacuum in Secondary wiring carries the induced coil
the manifold is determined by the engine voltage (20.000 volts or more) first from the
speed and the throttle opening With less air- coil's high tension terminal to the distributor
fuel mixture entering the cylinder and with the cap and then from the outside distributor cap
mixture being slightly riches e . not as much terminals to the spark plugs. Because of the
air). the mixture will burn slower In such a hi,h voltage they carry, these wires must be
t.:tuation spark must take place sooner The heavily insulated. The insulation must be oil
centrifugal advance can't advance the spark resistant and must also be able to withstand a
any further because it is in a set speed- fair amount of heat as the wires run close to
ad'. -ince ratio The furthc- advance is ac- the manifolds.
complished by a vacuum advance mechanism
(f=igures 8-114) Until the early sixties, secondary wiring was
made of about 16 gauge copper or aluminum
wire. At that time, wiring with carbon im-
pregnated liners or cores was introduced. The
carbon impregnated core provides a
rt. 'stance path for the high voltage surges
which helps eliminate radio and television in-
terference from the ignition system.

1 75
 BASIC ELECTRICITY 8:73

Other improvements have followed. such as

graphite saturated fiberglass cores and soft TERMINAL
silicone insulation that allow the wire to
withstand more heat and generally make it
more durable.
The ends of secondary wiring that fit onto the
distributor cap. the coil tower. and the spark INSULATOR
plugs are equipped with insulating boots. The
boots either slide over the cable or are bond-
ed to It
BALLAST RESISTOR
Earlier. a bypass ignition system was men- SEALING MATERIAL
tioned. When starting. a bypass circuit takes
full voltage to the coil for a hotter spark. but
once the engine starts. battery voltage passes
through a resistor which cuts the voltage to
the coil. The decreased voltage. because it
generates less heat, gives longer life to the STEEL
points. condenser and coil. The resistor used
IS called a ballast resistor. SHELL

I
Instead of a ballast resistor. some manufac-
turers use a resistance wire which is con-
nected between the ignition switch and the
Coil. Note that there IS no bypass circuit here.
When the conductor is cold at starting. vir- -REACH-
tually full voltage is sent to the coil. but as the
ELECTRODES
conductor heats up the resistance increases
and reduces the voltage. 1,41 SPARK GAP---".
(8-115) SPARK PLUG CONSTRUCTION
SPARK PLUGS Courtesy of John Deere Lid

When the topic of electrical circuits was in- The iligh voltage surge comes in through the
troduced. it was said that no current flowed in terminal, travels down the central electrode
an open circuit In most cases this IS true. and then jumps the gap to the bottom elec-
However. if the opening in the circuit is small trode. After the complex ignition act.on that
and a strong voltage is present. the circuit you have seen at the coil and distributor.
can still be completed. Strong voltage will current jumping The gap to create a spark
force the current to jump the opening or gap seems rather simple. The spark. however. is
to complete the circuit. Such a jumping of no: just any spark. it must be of the correct in-
current occurs at the spark plug gap to com- tensity and duration to cause efliciert fuel
plete the ignition circuit combustion. Spark plugs must be carefully
constructed tr, give such a controlled spark
Spark Plug Operation Plug Construction
A spark plug (Figure 8-115) has two con- All spark plugs have basically the same parts
ductors or electrodes One is connected by as the one shown above. Variations in plugs
wire to the distributor cap and the other IS result from these parts being designed dif-
connected to ground The two electrodes are ferently. Spark plug parts are discussed
separated by a small opening or gap below.

Outer Shell
Each spark plug has a steel outer shell. The
top of the shall IS hex-shaped for tightening
the plug when installing it The lower part of

1 76
8:74 BASIC ELECTRICITY

the shell is threaded and screws into the Heat Range Of Plugs
cylinder head. The grounded electrode ex-
tends out from the lower part of the shell A The heat range of a spark plug is another im-
gasket slips over the threaded portion of the portant plug characteristic. Heat range refers
plug and rests against the flange at tne bot- to the plugs ability to transfer heat at the firing
tom of the upper part of the shell The gasket tip to the engine's cooling system. A plug's
serves two purposes, it seals the plug against ability to transfer heat is determined by the
compression loss and provides a path for the distance the heat must travel. A short in-
transfer of heat to the cooling system. Note sulator seat quickly carries heat from the core
that instead of a gasket and flat flange some leaving a cold plug A long insulator seat
plugs will use a tapered seat. allows the core to retain maximum heat and
makes a hot plug (Figure 8-116).
The distance from the flange to the end of the
plug threads is called the reach. The roach of
a spark plug is very important in plug selec-
tion A plug with too long a reach will extend
too far into the combustion area Not only will
the plug run hotter, but it is also in danger of
being hit by a piston or valve A olug witn too
COLD HOT
short a reach will run cold and cause misfiring PLUG PLUG
due to fouled electrodes
The engine's Service Martial will give the
exact spark plug soecif,cations for each
engine.

.,park Plug Insula:or

SHOPT NOSE CONE LONG NOSE CONE
The insulated core or insulator is mounted . (8-116)
the outer shell Insulators are usually made of Courtesy of John Deere Lid
such insulating materials as wr..te ceramic or
porcelain The material must withstand ex- Engine design and operating conditions will
treme heat. cooling and vibration The in decide whether a hot or a cold plug shot be
sulator is held in position and shielded Irom used.
the outer shell by an inside gasket
sealing compound Beside., olding the cen- Generally. an engine which operates at fast
ter electrode. the ins 1-Or _ a snield for the spec ,::6 or heavy loads. i.e., the engine
electrode so that ant will flow only operates hoL will require a cold plug so that
th,ough the electrode The exposed upper the heat will transfer quinkly. On the other
portion of the insulator must be kept clean to hand. an engine that usuzNly operates at low
prevent current from escaping Many plugs or idle speeds will use a hot plug. The 1.30t
have ribbed insulators to discourage dirt plug will burn off the deposits that form on a
build-up. plug's electrodes when an engine operate,. at
Sew speed' for long periods of time.
Spark Plug Electrodes
The electrodes are usually made of a metal
alloy that can withstand constant burning and
erosion The gap between the two electrodes
is of prime importance in plug operation. Tnis
gap must be set to exact engine
specifications If the gap is too narrow the
spark will be weak and fouling and rntshi ng
will result: if too wide. the gap may work vr ?II
at low speeds. but at high speeds cr het y
loads it will strain the cc:I and nat. se
misfiring. The .S4rfaces of the two electrodes
at the spar, ing point or gap should be pa: lel
and have squared corners to give the evr, ant
a better lump across the gap.

177
 BASIC ELECTRICITY 8:75

Hot and cold plugs. the two extremes, are not

the only plugs available. For more normal
engine operations, a plug that is somewhere
between hot and cold is used. In Figure 8-117
note the length of heat travel in the different
plugs. as indicated by the length of the
arrows.

ENGINE
COOLING
SYSTEM

1:OT MEDIUM HOT MEDIUM COLD COLD

(8-117)" SPARK PLUGS OF VARIOUS HEAT RANGES Courtesy or ..10,1 Deere Lid.

CAM ANGLE (DWELL) AND BASIC TIMING long resulting in burned points that make
starting difficult.
Cam Dwell
Cam angle and timing are directly related;
Cam dwell is the number of degrees during one degree of cam angle change equals one
the rotation of the cam that the points remain degree of timing change. The relationship is
closed (Figure 8-'. 8). Important because as the rubbing block on
the contact points wears. the cam angle will
POINTS POINTS POINTS increase and so throw the timing out.
OPEN CLOSED
OPEN
Cam dwell defines contact point operation in
terms :f cam rotation and closed puints.
CAM Another way to look at point operation is in
ANGLE terms of the length of the gap between the
points when they are fully open. If points are
set according to cam dwell, a dwell meter is
used; if they are set by point gap. a feeler
gauge is used. Both the cam dwell and the
POINTS
point gap should be measured to get a correct
sitting of the contal points.
Basle Timing
CAM DIRECTION Setting the cam dwell or ooint gap is the first
OF ROTATION step 'n adjusting the disti'butor. The second
(8-118) CAM ANGLE (DWELL) step is called setting the basic or initial
Courtesy (A Juan tieere Ltd liming. Basic timing is adjusting the
Cam dwell is necessary to insure complete
dist:ibutor so that the spark occurs at the
correct time to give full combustion power.
build-up of the magnetic field within the cool, The distributor ,- adjusted by loosening the
or why:' * Called Coil saturation. If coil clamp and rotating the distributor in its
saturation is not reached. the amount of in-
mounting.
duced voltage from the coil will be reduced.
Cam angle will give a low spark at high Basic timing Is set with a timing light or
stroboscope (described later) while the
Spelds and cause ;misfiring. Excess cam engine is idling and there is no influence from
angle allows the poi Its to remain closed too
the Centrifugal advance.

178
8:76 BASIC ELECTRICITY

PREVENTIVE MAINTENANCE OF SPARK PLUG SERVICING

IGNITION SYSTEMS
Spark plug service has three steps (Figure 8-
Removing And Installing Spark Pings 119)

Pull the wire from the plug by grasping the inspection

terminal, not by pulling on the wire. cleaning
After loosening the plug. but before gap adjustment
removing it. always clean the area around
the spark plug by blowing. wiping. or CHECK WIPE CLEAN
brushing (Be sure to protect your eyes.) CRACKS
Cleaning in this way will prevent dirt from
falling into the cylinder after plug removal.
3 Use a deep-well socket to remove the
spark plugs Also remove the gaskets with
the plugs (if used).
4 II the plugs are to be reused. be sure to
note whicn cylinder each came from. The
condition of the spark plug can tell you a
lot about the operation of a particular
cyclmder REPLACE
GASKET
5 When replacing spark plugs, it is best to
CLEAN
replace all of them at the same time to ELECTRODES CLEAN
take full advantage of new plug per- INSULATION
UNTIL
lormance and economy. FILE AND RE-GAP WHITE

6 When installing spark plugs with gaskets.

be cure the gaskets are in place The (8-119)
gaskets act as a seal to prevent loss of MAINTENANCE OF SPARK PLUGS
compression around the plug. Without a Courtesy 01 Jonn Deere Lid
gasket. the reach of the plug would also
change. affecting plug operation. Inspection Of Spark Plugs
7 Remember another point about gaskets In most shops the practice is to replace plugs
Most manufacturers recommend installing after a reasonable service life or if they give
new gaskets with both new and recon- trouble. Whether plugs are reused or not. all
ditioned spark plugs Always remove the failed plugs should be carefully examined, as
9Id gasiiet from the spark plug Never use their condition can tell you many things about
botn the old anti the new gaskets as plug the state of the engine.
reach would be aflected
8 Tighten It ,e spark plugs to the torque Cleaning Spark Plugs
specified 9 e service manual II a torque Although cleaning spark plugs probably won't
wrench is not available. tighten the plug be a general practice. occasionally you may
unit! you leel it seat then turn it one-half want to clean them.
three-quarter turn more (With steel
gaskets. tighten one-quarter turn after 1 A sand-blasting machine is used to
seating ) remove deposits from the insulator and
electrodes. Carefully inspect the plug af-
9 Connect the spark plug wires to the ter blasting to insure that all the sand has
proper plugs been removed. as engine damage could
Tightening spark plugs to the correct result ti any was left on the plugs.
specif cations cannot be over-emphasized 2 Do not use a power wire brush to clean
Over torquing at best can make thq plugs dif- the plugs Most plug manufacturers do not
ficult to remove and at worst can break the recommend this method.
plug off at the threads Under torqued. loose
plugs result in poor heat transfer and reduced
plug Me
179
 BASIC ELECTRICITY 8:77

3 Badly fouled plugs should be replaced It reading even if the electrode surface is
is doubtful that sand blasting can remove not flat
311 the deposits from such plugs
2. If the gap is too wide. the plug may need
4 Clean the threads with a wire hand brush replacing.
or a powered soft wire brush wheel.
3. Use a bend nq tool to adjust the gap to
5 Wet. oily plugs may require cleaning with specificati, Often the bending tool is
a petroleum solvent before abrasive part of the luge as shown. After ad-
cleaning justing. check 4,, be sure the electrode
surfaces are parallel.
6 Before gapping the electrodes. file them
with a sinzill point tile to flatten their sur- 4 Never bend the center electrode as you
face at the firing point and to square up may crack or break the insulator tip.
the edges (Figure 8-120). Squaring the
surface edges can reduce spark voltage ADJUSTING THE CONTACT POINT
requirements even more than cleaning the GAP OR CAM DWELL
plugs does.
Generally points, like plugs, are replaced after
a reasonable service life or when they give
trouble. If it is necessary to reuse contact
points because new ones are not available.
dress the contact surfaces with a fine oil
stone. Be sure to clean the points thoroughly
before installing them.
The correct way to set points is first with a
feeler gauge and then with a dwell meter. If a
dwell meter is not available extra care should
be taken with the feeler c auge settings.
ELECTRODE 1. Adjust points with a feeler gauge: With
the breaker cam posit.oned so that the
FILE rubbing block touches a cam lobe at its
highest point. adjust the points with a
Al $731
feeler gauge to manufacturer's
(8-120) specifications
FILLING THE SPARK PLUG ELECTRODES
Courtesy 0 John Deere Lid 2 Adjust points with a dwell meter: A °well
Adjusting Spark Plug Gaps meter can be part of a distributor machine
or it may be a separate portable unit. The
1 Whether a plug is new or used. alway, latter is the most likely to be found in a
check the gap before you install it (Figure heavy duty shop Following directions.
8-121) connect up the dwell meter. crank the
engine and adjust the points to the
.4
specific dwell angle.
Note:
If the cam angle reading on the meter varies
more than two degrees between lobes look for
a won; drive shaft or bushings.
It a problem is encountered in trying to obtain
0 63 mm the correct setting. check for the following
(025")
possibilities:
(8-121) improper spring tension
CHECKING THE SPARK PLUG GAP
(-ourtesy 0 John Deere Ltd
wrong contact point assembly
worn breaker cam
Use a wire spark plug gauge to check the
gap The wire gauge will give a true gap worn distributor shaft and bushing

180

: - '
8:78 BASIC ELECTRICITY

USE OF TIMING LIGHT WIRING HARNESS

Once the point gap or cam dwell has been ad Wiring for electrical accessories in vehicles is
justed. the basic or initial timing can be set bound together in trunk lines called a wiring
Basic timing is done while the engine is harness. A vehicle may have tour or five har-
idling The object of basic timing is to match ness lines supplying electricity to different
up the timing mark on the turr:ng crankshaft parts of the vehicle. Branch wires come oft
pulley (on the flywheel on some older the harness trunk and connect up to their
ensures) with a fixed mark or timing pointer specific accessories. The harness sheath can
on tile timing cover or housing. To match up be made of rubber. cloth. plastic, plastic
these marks a timiiig light (a st000scopic tubing or can simply be electrical tape wrap-
light) is used The timing light is connected to ped around the wires. Two points when
the vehicle's battery and to the number one working on a harness:
cylinder spark plug lead. Every time number
one cylinder fires. the light will flash. Directed Care must be taken when installing, a har-
at the fixed mark and the crankshaft pulley. ness not to interfere with any moving parts
the flashing light will make the pulley appear of the vehicle Install clips correctly so
to stand still, and you will be able to see how that they do not pinch the wires and cause
far the two marks are out. Or ::e you have seen short circuits.
that the timing is out. loosen the distributor 2 Individual wires can be replaced by run-
holding clamp and while sial watching the ning a new wire around the harness. Do
timing light turn the distributor one way or the not try to thread new wires through the
other to bring the two marks together (Figure harness Attach the new wires to the har-
8-122) With the marks matched up. tighten ness with tape or clips. Be sure to cut oft
the holding clamp, stop the engine and the defective wire right where it comes
remove the timing light. out the harness.

Replacing Wiring
1 Since the size of wiring is related to the
load it must carry. always replace a defec-
tive wire with the same gauge wiring as
the original. Never use undersized wiring
because it will overheat and possibly burn
through.
2 When installing additional accessories on
a vehicle. such as extra lights, and an
existing circuit is used. the circuit may
have to be re ,,ired with heavier wire to
carry the au, load.
The gauge or size of an electrical wire
depends on' r

(a) Total lengtn of the wire in the circuit.

(b) Total amperes that the wire will carry.
A4230,

(3 .122) TIMING MARKS (TYPICAL) Refer to a wire catalogue for wire size and
Courtesy of General Motors Corporation load carrying capacity.
Two points to note when setting the timing: 3 When replacing a faulty wire end. it is best
to solder the connection onto the wire.
1 Be sure the idle speed is as spec,:ied by Use only rosin core ler. 1 he other
the manufacturer. alternative is a crimp .. wire connector.
2. Moat manufacturers recommend that the Crimp-on connectilns a okay in a clean
vacuum line to the advance unit be environment. but if the ..re used in a
corrosive area the ^or.: $cliuns tend to
disconnected when setting basic timing. deteriorate. Crimp-on connectors should
Don't forget to reconnect the line after the
timing has been sc.t. be fastened with crimping pliers.

1 81
 BASIC ELECTRICITY 8:79

FUSES (e) Use of incorrect size fuses in the cir-

cuit.
From the discussion on basic electricity you
N
remember that given a set voltage source, (f) Fuse located too near a hot area
such as a battery. the amount of current is such as an engine or a heater.
governed by the amount of resistance in the (g) Vibrations near the fuse. causing the
circuit. You can see the current resistance fuse contacts to come loose.
relationship in the formula:
volts 2. If a fuse is blown by overloading the glass
amps = will be clear; if blown from a short circuit
ohms the glass will be dark.
\ As the resistance (ohms) gets greater the
current (amps) gets smaller, and vice versa. 3 If the fuse in a circuit repeatedly blows.
as the resistance gets smaller the current gets and no short circuit exists, it means that
greater. the circuit is overloaded and is not meant
to carry the loads being placed upon it.
In a vehicle all electrical circuits have a
resistor of some kind to control the amount of 4 Always place a blown fuse with one of
current flow. What would happen. though, if the same size. Never use a fuse with a
an overload or a short circuit occurred? higher amperage rating as it may cause
Current would rapidly increase to the point serious damage to the circuit it is sup-
where the wire would burn up. To protect posed to protect.
against si.ch excessive amounts of current,
fuses or circuit breakers are connected to the
circuit. When the current gets beyond a safe
level the fuse blows, breaking the circuit and
stopping the flow of current
A fuse consists of a fine wire or thin metal
strip enclosed in a glass or fire resistant piece
of tubing Most fuses used in industrial equip-
ment are of the small replaceable type as
shown in Figure 8-123.

(8-123)
Courtesy or Jowl Deere Ltd

The fuses for all the circuits in the vehicle are

located in a central fuse panel where they can
be easily replaced.

Points On Fuses
1 BLOWN FUSES ARE USUALLY CAUSED
I BY
(a) A short circuit in the electrical circuit
caused 63y defective wiring or a
defective component (lights. motor,
etc )
(b) An overk.ad in the circuit caused by
a surge of electricity passing through
the circuit.
(c) Poor contacts in the electrical circuit
(d) Overheatir g in the circuit caused by
overloads or poor contacts.
182
r
8:8C BASIC ELECTRICITY

QUESTIONS IGNITION CIRCUIT 10 The distributor is driven at

1. Briefly state the purpose of the ignition (a) crank shaft speed
syste m
(b) one-half crarie.shaft speed
2 What are the two circuits of an ignition (c) twice crankshaft speed
system. State what each circuit consists
(d) Onequarter crankshaft speed
of and what. in general terms. is the
voltage.
11. The centrifugal advance mechanism
3 What is the purpose of the primary circuit controls the spark timing by sensing
in the ignition system? engine'
4 What occurs in the ignition coil when the (a) temperature
points open? (b) power
5. Self-induced voltage in the primary win- (c) speed
ding of the coil is absorbed by the
(d) oil pressure
(a) wires
12 A is used in conjunction
(b) battery with a centrifugal advance mechanism to
(c) distributor improve spark timing.
(d) condensor 13 A ballast resistor used in the ignition
system improves the Ide of me:
6 The ignition ballast resistor in the
primary circuit' (a) cod
(a) is connected in series for cranking (b) condensor
and parallel for operation. (c) points
WI is connected to bypass for starting (4) all the above
and series for operation
14. A spark plug:
(c) is used to decrease ignition current
d'iring cranking (a) makes the spark to fire the air-fuel
(d) If.. only required for dual ignition mixture
systems. (b) increases the spark intensity
7 In the ignition coil one end of the secon- (c) controls the spark timing
dary winding is connected to the high (d) provides a gap for the spark to jump
tension terminal and the other end to the across inside the combustion cham-
ber
(a) rotor
(b) primary winding 15. What term is used for spark plug
operating temperature?
(c) condensor
(d) points (a) heat travel
(b) reach
8 How can reverse coil polarity be correc-
ted (c) the number system
(d) heat range
(a) change the battery polarity
(b) change the ignition cod 16. What determines the heat range of a
spark plug?
(c) reverse the secondary wires
(d) reverse the primary wires (a) engine horsepower
(b) number of cylinders
9 What three jobs must the distributor per-
form? (c) engine design and operating con-
ditions
(d) whether the engine is a two stoke or
four stroke

18d
 BASIC ELECTRICITY 811

17 Dwell may be defined as the number of

degrees of cam rotation when the points
are
18 As the cam angle increases the spark
timing wilt'
(a) advance
(b) retard
(c) not change

19. What two methods can be used to set the

points?
20 What are the effects of loose or under-
torqued spark plugs?
21 True or False? Generally speaking, spark
plugs should be replaced as a set
22. True or False? Badly fouled plugs should
be replaced rather than cleaning them.
23 What effect does filing the gap have on a
used spark plug's performance?
24 What is the rec(46,-.^..anded tool for
checking spark plug gap?
(a) flat feeler gauge
(b) stepped feeler gauge
(c) wire feeler gauge
(d) dial indicator
25 When adjusting the initial timing using a
timing light. tt is recommen led that the
engine be and the
be disconnected
26 The gauge oi size of e!ectrioal wiring
depends on
(a) the size of battery
(b) the total length of the wire in the cir-
cuit
(c) the total amperage that the wire will
carry
(d) both (b) and (c) are correct
27 True or False? If a fuse keeps blowing
and there is no short circuit. put in a
heavier fuse
28 To obtain the best possible connection
when replacing wire ends. they should
be
(a) crimped on
(b) pushed on
(c) soldered on
184
8:82 BASIC ELECTRICITY

ANSWERS ELECTRICITY THEORY 21. (a) to (c)

1. (b) negative to positive. (b) to (a)
2 (c) energy. (c) to (b)

3.
22. (d) red for positive. black for negative
True.
23 1. Strength of the magnetic field.
4. Voltage is the force that causes current
to flow in a conductor. 2. The speed at which the lines of force
are cut.
5. (d) ohm.
3. The number of conductors cutting
6. Voltage source. e.g.. battery across the lines of force.
Resistor. e g . light bulb 24. . . move towards -

Conductor, e.g.. copper wire 25 .. move away from

7 (a) to (b)
`41:4 to (c)
(c) to (a)

E 12
8 = 3 amperes
R 4

9 Any substance that as a goo° transmitter

of electricity.
10 A closed circuit has a resistor to control
the amount of current flowing in the Cir-
cuit In a short circuit the current takes a
short cut by passing the resistor Since
the short circuit has no resistor, current
becomes very high and will usually burn
out the conductor (or fuse :f there is
one).
11. .. direct OC
12. West a measurement of electrical
power found t elying volts times
amperes
13 Series, Parallel, SdriesParallel
14. (c) low resistance high amperage.
15. ... magnf .c field. Like poles repel.
unlike poles attract
16. Both have a magnetic field surrounding
them. The stronger the current in s con-
ductor. the stronger its magnetic field.
17. Place an iron core in the center of the
coil.
18. (d) ampere turns
-49
Electromagnetic induction
20 False Either the conductor moving
across the field or the field across the
conductor will induce a current.
165
 BASIC ELECTRICITY 8:83

ANSWERS BATTERIES
1 (c) lead peroxide in the positive plate.
2. negatlie plate group
positive plate group
separators and connecting straps
3. When it is immersed in the electrolyte
4. (d) 2-volts.
5. True.
6. (d) 1.270

7. True
8. (c) water
9. Prior to use, a dry-charged battery
retains its full state of charge provided
no moisture enters the cells. whereas a
wet charged battery requires periodic
reotwgirlg to maintain its charge
10. Wet-charged.
11. The plates are enclosed in envelopes
which act as separators.
12. They require less maintenance, are more
dependable and will last longer.
13. Temperature, battery's operating cycle,
and the state of the battery's charge.
14 Cold power rating the amount of
power or amperage that a battery will
supply for starting on cold days.
Reserve capacity the period of time
that a battery by itself (i.e., without the
generator or alternator) will supply an
adequate amount of power to operate a
vehicle's electrical circuits.
15 False.
16. . .. the power requirements of the
engine it must start.
17. ... self discharge.
18 (b) baking soda
19 (d) water
20 (c) disconnect the grounded terminal
cable
21 (d) all of the above are necessary.
186

N
 44 .

8:84 BASIC ELECTRICITY

ANSWERS BATTERY TESTING

1 (a) a hydrometer
2 (d) 030
3 (b) 9.6-volts
4 1-volt
5. True
6 A load test

187
 BASIC ELECTRICITY 8:85

ANSWERS BATTERY CHARGING

1 (b) 7 amps 7 positive plates and 8
negative plates.
2 A slow charger because it does a more
thorough job of chemically renewing the
plates.
3 (b) series.
4 1 The temperature should not exceed
15 C (125 F)
1 The electrolyte shouldn't become
cloudy with sediment.
5 (b) Hydrogen
5 False. It is damaging to batteries to
overcharge them
7 (c) disconnect a battery cable
8 (a) a longer charge
9 . off . .

10 False
8:86 BASIC ELECTRICITY

ANSWERS STARTER MOTOR

1 (d) mechanical energy.
2 True
3 (b) a force to be exerted on the con-
ductor
4 (c) movement c..f a magnetized core into
and out of an electromagnetic coil.
5 The magnetic switch completes the cir-
cuit between the oatte.y and the starter
motor. whereas the solenoid not only
completes the circuit, but also provides a
mechanical means of shifting the starter
motor pinion into mesh with the flywheel.
6 (a) connect two batteries in series for
starting and in parallel for charging.
7. 1 Transmits drive torque from the star-
ter motor to the engine flywheel
2 Provides a gear reduct:on.
8 (c) remove the battery ground strap
9. Centrifugal force acts on the coun-
terweight and causing the pinion to spin
into and out of mesh with the flywheel
10 ... overrun ...
11. ... magnetic ... solenoid ...

189
 BASIC ELECTRICITY 8:87

ANSWERS CHARGING SYSTEM

1. (b) supplies all current.
2 (e) a commutator and brusnes.
3. 1. opens and closes the charging cir-
cuits.
2. prevents overcharging of the battery.

3. limits the generator's outout to a safe

limit
4. (c) diodes
5 (a) Limit the voltage to a safe value.
6 In a generator current is induced by
moving conductors through a stationary
field.
In an alternator current is induced by
moving a held by a stationary conductor.
7. True.

190
8:88 BASIC ELECTRICITY

ANSWERS IGNITION CIRCUIT 22. True.

1 To take low voltage from the battery and 23. Filing reduces the voltage requirement to
create nigh voltage to fire the engine. send a spark across the gap.
2 Primary Circuit ignition circuit. 24. (c) wire feeler gauge.
primary winding in Coll. points and con-
denser. low voltage. ;5. ... idling .. . vacuum line to the advance
Secondary Circuit secondary winding
in coil, distribution cap and rotor and 26. (d) both (b) and (c) are correct
spark plugs; high voltage.
27. False.
3 To create and collapse a magnetic field
in the ignition coil. 28. (c) soldered on.

4 The magnetic field created by the

current flow through the primary winding
collapses across the secondary winding
inducing a high voltage in the secondary
winding.
5 (d) condenser
6. (b) is connected to bypass for starting
and series for operation.
7 (b) primary winding
8 (d) reverse the primary wires
9 1. opens and closes the primary circuit.
2 times the high voltage surges.
3 delivers the current to the spark
plugs.
10. (b) one-half crankshaft speed.
11 (c) speed
12. .. vacuum advance ...
13. (d) All of the above.
14. (d) provides a gap for the spark to jump
across inside the combustion chamber.
15. (d) heat range
16. (c) engine design and operating con-
ditions.
17 .. closed.
18. (b) retard
19. Use a dwell meter to set the cam dwell.
or a feeler gauge to set the point gap.
rhe dwell meter is the most accurate
method.
20. Poor heat transfer which will shorten
plug life.
21. True.

191
 BASIC ELECTRICITY 8:89

ELECTRICITY TASKS IGNITION SYSTEM

BATTERIES 1. Service the spark plugs on an engine.

Remove the plugs. clean, gap and rein
Preventive Maintenance On Batteries stall them. or if the plugs are not ser
viceable replace them with ones of the
1. Safely usv jumper cables to start a correct type and heat range as stated in
vehicle. the service manual. Using a torque
wrench, tighten the plugs to the torque
2. Completely service a battery: given in the service manual.
(a) Remove the battery using correct 2. If ignition testing equipment is available,
tools and safety procedures. check and adjust dwell and ignition timing
(b) Clean the battery with baking soda to the specifications stated in the service
and water and dry off the case. manual.
(c) Check the water level and add water 3. Get experience working with electrical
if low. wiring:
(d) Test the battery as accurately as you
have equipment for. If you have a bat- (a) Select correct wire sizes.
tery test meter, follow the msiter's (b) Solder wire ends using rosin core
operating instructions. solder.
(e) Charge the battuu. Get experience (c) Fuse circuits for a safe amperage
using both slow and fast chargers. draw.
(I) Install the battery ensuring that the (d) Install a fight or similar electrical
battery box and hoiddown are in component, ensuring it has good
good condition. grounding.

STARTING MOTOR AND GENERATOR

Safety
1. Practice safety by disconnecting the bat-
tery before working on any electrical com-
ponent to prevent short circuits.

Routine Maintenance Check

1. Check the condition and tension of the
generator belt(s). If necessary adjust the
tension. If the belt(s) are not serviceable
install and adjust a new one(s).
2. Check the condition of the generator
pulleys, and repair or rerlace, if
necessary. Check pulley alignment.

Service Repair
1. Remove and install a starter motor and a
generator using the correct tools and
procedures outlined in the service
manual.

192
 BLOCK

Winches
 WINCHES 9:1

TRACTOR MOUNTED WINCHES Drums on winches are large, spool-shaped,

A tractor mounted winch (Figure 9-1) is a sim- steel castings. They're driven by the winches
ple gear reduction assembly mounted at the reduction gearing (Figure 9-3). Cable (wire
rear of the machine. By using cables, these rope) is attached to the drum and is wound
winches can reel in heavy loads or hold the onto the drum's surface or lagging.
loads while they are dragged the winches
are driven either by a:
1. Live power take-off (P.T.O.) shaft (Figure
9-2) from the torque converter
2. Live P.T O. shaft tram a manual trans-
mission (not common today)
3 Hydraulic motor.

REDUCTION
GEARING

Cangani oneoll year train (9-3)

Courtesy of Carco Winch Products

Most crawler tractors have single drum win-

ches However. some special application trac-
tors will use two or more drums and each
drum will have its own controls. For example.
multiple drum winches would be uSee on a
tractor doing yarding work in logging or on a
tractor working in electrical transmission line
(9-1)
construction. The discussion in this manual
Courtesy of 1-1vSter Company
limits itself to single drum winches.

(9.2) Courtesy ol Caterpillar Tractor Company

194
9:2 WINCHES

Cable may be wound onto the drum in one of There are advantages and disadvantages in
two ways overwind or underwind Overwind both ways of winding. Overwind tilts the load
winds from the top of the drum and un- so it doesn't dig in. but when loads are heavy
derwinds from the bottom (Figure 9-4) this lilting can cause the tractor to rear. Con-
veesely. underwind gives a straight pull that
won't cause the tractor to rear but the load
will have a tendency to dig in. Unless an un-
derwind is requested. winches come from the
factory set for overwind.
I t is a major job to change from overwind to
underwind or vice versa. Internal changes to
both the winch gearing and the line position
have to be made. Also. if the machine has an
automatically applied mechanical brake. it too
requires alterations.

TRACTOR WINCH RATINGS

Tractor winches are rated according to their
WPM "line pull" and their "line speed". Line pull
IJNDERWINDING
(9-4) means the maximum amount (in kilograms or
Couriosy of !Oster Company lbs.) of pulling strength a winch can exert on
its cable. while line speed is simply the speed
at which the cable travels faster. Line speed
will vary with the tractor horsepower. the size
of the drum. and the layers of cable wrapped
around the drum (i e.. cable travels slower as
more of it wraps around the drum) Drum size
(i.e.. cable capacity) IS another factor In rating
a winch. One manufacturer's ratings or
specifications for its different winch models
are shown in Figure 9-5

OVERWINDING
(9-41
Courtesy of HySiet Company

Performance and SpecificatIons (9-5)

PSIPSM (Power Shift/Power Shift Manual)
UM SPEED ORUM

MODEL
APPROXIMATE RARE DAUM {depending on
SNIPPING WT r LINE PULL ttoMor lip) 1%" l 1 is- lr CASTE CAPACITIES
ti- 1/4" ti," l env - A
DIMENSIONS
S C

740 5113.0mm 21271b 500001) 5010 S60 rim moo 230 ft 30011 440 ft *I m 18 to 121tm
F50 111Cop. Drum 112710 r.0.000 lb 5910 150 fpm 215 11 306 fl 42011 500 ft 8 in 19 m i3Nin
0.00 SM. Drum 3264 10 80.0001b 5010 1501pm 185 0 2500 3400 476 0 1210 22 m 1314m
040 111-Cop. Drum 325410 00,000 lb 50113 150 Om 260 ft 316 tl 4200 675 ft 9 la 221n 14%in
.1 A Std. Drum 4086 lb no coo lb saw 00Ipm 166 0 200 0 270 0 MO II 13 m 24 en 12 In
4,120 iii-C.p.Onin 405610 120,00010 5010 160 fpm 225 ft 3001t 400 II 525 11 101n 24 in 140fin

NOTE Potionnanb, figures bison on Dower town of OM *now

throw Wino fine NANO will very valn to quo converter
Getout *mot is dependent on *none loud end Weed

Comm rtOSY Of CarCo Winch Pppclioc ts

195
 WINCHES 9:3

TYPES OF SINGLE-DRUM stationary. The gear positions would be

TRACTOR-MOUNTED WINCHES mechanically actuated by a shift lever after
the engine clutch had interrupted power to
There are three main types of tractor-mounted the P.T.O. shaft. Note that free spool for quick
winches wind out can be obtained by ieleasing the
1. direct drive sliding gear brake when the winch is in neutral.
2. power shift hydraulic control constant
mesh gear
3. hydraulic drive
Direct drive and power shift winches are
driven by the tractor engine through use of a
PT 0. shaft. A hydraulic drive winch is driven
by a hydraulic motor.

DIRECT DRIVE SLIDING GEAR

A simplified view of a direct drive sliding gear
winch is shown in Figure 9-6. A direct drive
winch has no clutch. Before the winch can be
shifted. the master clutch between the engine
(9-7) NEUTRAL, DIRECT DRIVE
and transmission has to be disengaged so
that power to the P.T.O. shaft is interrupted.

(9-7) FORWARD. DIRECT DRIVE

t FTOSmAFT
2 BEVEL GEAR
3 BEVEL GEAR SHAFT
4 2N0 REDUCTION PINION
S 2N0 REDUCTION GEAR
6 BRAKE SHAFT
7 INTERMEDIATE MOON
8 0NTERMEDIATE Gem
9 DRUM PINION
10 ORum GEAR
ii DAUM
12 INTERMEDIATE PINION
13 CLUTCH
m SHIFTER SHAFT
16 BRAKE WHEEL

(9-6)
Courtesy of Hyster Company

Figure 9-7 shows the power flow or gear

movement when the winch is in neutral. for- (9 -7) REVERSE. DIRECT DRIVE
ward and reverse. The shaded gears and
shafts are moving. the unshaded ones are Courtesy of HySter Company

196
9:4 WINCHES

Other points about direct e,ive win.:.hes A hydraulic pump. located either critside or in-
side tha winch supplies the pressure and flow
Lubrication is by splash. The winch to operate the clutch packs. Power shift win-
case or housing serves as the oil reser- ches have the advantage over direct drive
voir and it has drain, fill. and on level winches of being able to winch-in or winch-
plugs out while the machine is moving. Figures 9-9
Line pull power is controlled by the and 9-10 show power shift winches.
engine speed. Power shift winches have either a single or
Brakes for these winches are usually double lever control The double lever model
an external contracting bane-type has one levee for shifting into forward. reverse
located outside the gear case in a or neutra: and anotner lever to apply the
separate compartment. The band cor- brake A single lever model curies out all of
tracts around a gear shaft, thus holding these operations with one lever the brake is
the gear and stopping the drum from applied witomatically when the lever is moved
turning. The brake is a dry-type anu is from forward or reverse to neutral. and vice
controlled by a lever beside the shift veiza. the brake is released when the lever is
lever (Figure 9-8). moved from net.tral to tine of the gears. On
both models the shifting lever activates the

BRAKE
LEVER

EXTERNAL
CONTRACTING
BAND

SHIFT
LEVER
0.8)

Courtesy 01 Carco Win-h :Nactuets

hydraulic control valve which sends hydraulic
pressure to apply one of the multi-disc clutch
packs. The clutch packs then set the constant
mesh gears in a forward or reverse mode.
Generally. brakes on power winches are
POWER SHIFT WINCHES spring applied and hydraulically released The
brakes are external contracting band or multi -
A power shill winch has virtually the ;ame aisc.
drum and set of gears as a direct drive winch.
Both winches are driven by a live P.T.O shaft Power shift winches. like direct drive winches
Where they differ is in the way that the win- can free spool. Some manufacturers offer an
ches are shiftea To shift a direct drive winch optional free spool lever which operates a
the engine master clutch is disengaged and disconnect gear that allows cable to be freely
the winch s sliduig gear is mechanically shif- drawn from the drum. In the case of a single
ted. Power shift winches. on the other hand. lever power shift. the lever has a free spool
have hydraulically activated clutch packs and position where the winch is in neutral and the
constant mesh gears for shifting. Two clutch brake is not applied. Figures 9-9 and 9-10
picks are used. one forward and one reverse show power shift winches. note the clutches

197
 WINCHES 9:5
-s
The housing of both powershif. -1 direr.I
drive winches serves as an oil -ervoir
However. lubri..alion is only partly by ;,.ash.
The remainder of the lubrication (and cooling)
is carried out by pressure fed oil The oil is
pressurized from art engine dr,,en pump.

w6E

$ PIO Si-.441
2 avec GEAR '9-9)
3 01vEt GfAti ., AF 1
4 2ND Ilk oveilqp, porvuov Power Controlled
5 ?NO *It Our.1soN GE AR
8 BRAKE VoAs .
i $141EnklEOA1f eiNsOlso
8 $0416 Awl 01A: e <A AR
9 01tv$A P1000N
10 ['RUM (AAA Wax W120
:1 f ftvso
12 641E foot 0,A1E PINION
13 011. (.1.1,11CH
14 OIL BRAKE
1$ CONTROL VALVE

Courtesy of Hyster Company

SUCTION
STRAINER
RETURN FILTER
SOLID BAR
CABLE GUARD

MULTIPLE DISC
FRICTION CLUTCHES

CAST STEEL CASE

(9-101

SINGLE LEVER
CONTPOL

PRESSURE LUBRICATED
BEVEL PINION
i ...-i,
SPRING-APPLIED,
HYDRAULICALLY
RELEASED BRAKE

Courtesy of Carco Welch Products

198
9:6 WINCHES

HYDRAULIC WINCHES The sliding-gear hydraulic winch works the

same as the direct drive model described
Hydraulic winches can be installed on any earlier. The only difference is that it's driven
vehicle that has an adequate hydraulic by a hydraulic motor rather than by a P.T.O.
system They are not limited to crawlers. The shaft. The hydraulic motor is driven by a
main advantage of a hydraulic winch over hydraulic pump mounted on the engine. The
P T 0 shaft-driven power shift and direct drive planetary model shown here has two
winches is that the hydraulic winch can be planetary gear sets. one in the primary drive
mounted wherever ycu want it providing that housing and one in the final drive housing.
hydraulic lines can be connected to it. The primary drive housing contains a
Two Types of hydraulic winches. sliding gear hydraulic motor which drives trse sun gear of
and planetary. are illustrated in Figures 9-11 the primary reduction gear set The ring gear
and 9-12 and are discussed below. is held by a spring-applied brake. and output
power is transmitted by the planet carrier to a
shaft which passes through the center of the

Hyd aulic Motor \:-

reversible io 14.6.1 Solid Bar Cable Guard
provide 2 speeds t,
in each 'e;
\N. -.4-,
winch direction ,e.

Duai Controls-
separaie brake
and shift levers
for positive
control
Cast Steel Case

Manual Brake with

reversible band
Optional
Overrunning Brake
(9-11) SLIDING GEAR HYDRAULIC DRIVE WINCH
Courtesy of Carco Winch Products

PRIMARY
PLANETARY
FINAL PLANETARY
REDUCTION
REDUCTION

HYDRAULIC
GEAR
MOTOR

WINCH BARREL
(9-12) PLANETARY HYDRAULIC DRIVE WINCH
Courtesy of Gearmatic Company

199
 WINCHES 9:7

winch barrel to the sun gear of the final 1. External contracting band brakes
planetary reduction. The ring gear in the final
planetary is also held. The planet carrier is 2. Multi-disc brakes
connected directly to the winch drum by a
splined hub and thus transmits power to the EXTERNAL CONTRACTING BAND BRAKES
drum In this planetary arrangement a double External contracting band brakes are the
reduction is obtained Note that the planetary same type of brakes that are used for crawler
gear sets operate in either direction depen- steering. The band brake works in con-
ding on which way the hydraulic motor is junction with forward and reverse gears
driven giving control over the load when it is being
Two types of brakes are used on this raised or lowered. Some band brakes are
planetary winch; one brake permits a high manually applied with a separate lever.
reverse line speed and the other gives a whereas others are applied automatically.
uniform line speed in both reel-in and reel-out Automatic brakes are usually spring-applied
directions. Lubrication is by splash. as it is in and hydraulic-release. Hand applied brakes
the sliding gear hydraulic winch. are used where more accurate winch control
IS desired. In the powershift winch in Figure 9-
Hydraulic planetary winches are very common 13 the automatic band brake is shown on the
and are available in a variety of sizes and winch, while the manual brake is inset. Note
capacities. on the automatic brake the hydraulic release
cylinder and the large brake apply spring.
Winch clutches. brakes and hydraulic systems Also note the optional heavy duty brake lust to
are described below. the left of the large gear driving the drum.
Some winch models offer dual braking for ad-
WINCH BRAKES ded safety and load control. This second band
There are two main types of winch brakes: brake is lever applied.
Optional Heavy
Otsty Brake

Multiple Disci
Friction Clutches

Optional
Automatic
Blair*

Stow Speed
Gears
J-120-PSO
OPTIONAL HEAVY
DUTY BRAKE
SYSTEM

(9-13) STANDARD MANUAL BRAKE SYSTEM

Courtesy of Carco winch Producis
 9:8 WINCHES

AUTOMATIC BRAKE OPERATION The brake wheel is held stationary by a brake

band that is applied with a lever. The hub is
AUTOMATIC BRAKE ON splined to a driven shaft. and the hub and
POWERSHIFT WINCHES pawl assembly rotate around the inside of the
The brake is applied in neutral position
brake wheel ratchet ring. When cable i5
(Figure 9-14) When the control lever is moved reeled in. the panel slides over the ratchet
away frc -.eutral. eithe to reel-in or reel-out ring When the control is moved from reel-in
to neutral. the pawl engages with the nearest
position. oil pressure 83 led to the brake
ratchet tooth and locks the. hub to the brake
release cylinder to release the brake At the
same time oil is sent to the clutch packs to wheel automatically stopping any further feed
out
engage the clutch. Moving the control back to
neutral simultaneously releases the clutch If cable reel-out or free spool is desired the
and dumps oil from the brake release cylinder band brake is released by the brake lever.
allowing the brakes to be spring applied The When the band is released. the brake wheel
brake itself can either be a contracting band will revolve with the engaged pawl assembly
or multi disc and the cable will feed out.
This automatic brake can be used for un-
NEUTRAL-0° derwind or overwind. Overwinding is stamped
on one side of the brake assembly. and un-
0. derwinding on the other side (Figure 9-16).

(9-14)
COureSty of Carco Winch Products

AUTOMATIC BRAKES ON DIRECT

DRIVE WINCHES
One manufacturer of wincheS. Hyster. has an
over-running brake referred to as automatic.
This brake is offered as an option to the stan-
dard bralce band. Its operation is shown in
Figure 9-15 and described below.
PAWL BRAKE WHEEL
ASSEMBLY iS HELD STATIONARY
BY BRAKE BAND
DIRECTION
OF REEL-8N BRAKE WHEEL
RATCHET RING

V, WI

COWieSy 0/ Hyster Contonv

RATCHET HUB AND PAWL
ASSEMBLY ARE The assembly must be installed on the brake
REEL
SIDE VIEW DRIVEN BY THE shaft so that the desired wind faces outward.
(9-15) BRAKE SHAFT Also. the brake wheel must match the wind.
Courtesy of Hyster Company

201
 WINCHES 9:9

MULTI-DISC BRAKES
Some models of winches are now usinc an oil
cooled multi-disc brake similar to that in
Figure 9-17. This disc brake is spring-applied
by the belleville spring and hydraulically
released When the tract )r is stopped. or the
winch control is in neutral, spring pressure
applies the brake by squeezing the splinded
discs of the pack together against a pressure
plate. When the control is moved to reel-in
(forward) or reel-out (reverse). oil pressure is
applied to the piston and releases the brakes.

FRICTION DISC.
(11 RECYD1 PISTON
PRESSURE
HOUSING
PLATE
CAGE

PUSH ROD

THRUST
RING

COOLING SEPARATOR PLATE

OIL LINE (10 RED.D)

PISTON
COVER

HUB

BELLEVILLE
SPRING

PRESSURE INLET
FITTING

COOLING OIL
OUTLET
(4 PLACES)

COurlosV 00 HYSter Company

(9-17)

202
910 WINCHES

POWER SHIFT CLUTCHES Besides lubricating the gears, oil in the winch
housing also acts as a hydraulic fluid to apply
Clutch packs used in powershift winches are the clutch packs. Winch oil is usually the
similar to those used in powershift trans- same type as that used in the tractor's trans-
missions and in crawler steering clutches mission. 011 pressure for the winch is usually
The packs are muitidisc made up of exter- supplied by an engine driven pump (Figure 9-
nally splined steel discs alternating with in- 19). Hoses connect the pump with the winch.
ternally splined. lined discs (Figure 9-18) The When the engine is running. the pump cir-
size of the pack its diameter and thickness, is culates pressurized oil through the control
dependent on the size of the winch Clutch system to apply the clutches and release the
packs for forward and reverse are usually brake and also to lubricate the winch. Note
identical on larger winches. but on smaller that the winch housing acts as a radiator to
winches the packs for the two gears can vary cool the oil as well as acting as the oil reser-
in size Winch clutch packs are hydraulically voir
applied and spring released

CLUTCH DISCS

(9-19)

CLUTCH
PISTON

BELLEvILLE
SPRINGS

HYDRAULIC PUMP
DRIVEN OFF THE ENGINE PTO

(9-18)
Colatesy of Hyster Company

Connnsy of Hyste( Company

203
 WINCHES 9:11

Figure 9-20 shows a winch hydraulic system.

Note the suction and pressure filters which
protect the pump. control valve, clutches and
the rest of the system from any contaminants
in the Oli Also note the relief valve which
regulates oil pressure in the system
(9-20)

REVERSE
FORWARD
PUMP PRESSURE
PRESSURE
*NO COOLING
ANO COOLING
OIL LINE
TO PRESSURE OIL UNE
GAUGE

SUCTION
Frk TER

PRESSURE
FILTER

CONTROL
VALVE

REVERSE
BRAKE CLUTCH
COOLING 'Wm HANOI
OIL LINE
DUMP
OIL
VALVE FORWARD
BRAKE
ASSEMBLY
iLEP T HANOI

Courtesy of Hyster Company

A recent change in winch design by one

manufacturer includes the hydraulic pump as
part of the winch unit. The pump IP located in-
11(
side the winch housing and IS eriven by the
PTO shaft (Figure 9-21).

(9-21)

VALVE
PUMP

FILTER

SUCTION
:, SCREEN

Courtesy of Hysier Company

204
9:12 WINCHES

The advantage of a winch with a self-

contained hydraulic pump is that it eliminates
the need for hydraulic lines between the trac-
tor and the winch thus greatly simplifying
removal and installation procedures
(especially on machines using other back-end
equipment such as a ripper) The only lines
from the winch to the tractor are a control
cable and a gauge pressure line Eliminating
the hydraulic lines means that there is no
chance (or a suction hose leak and much less
chance of contaminating the oil when
removing and mstalltng the winch

WINCH OPTIONS
A high capacity drum and a lairlead (Figure 9-
22) are two examples of options offered for
winches A bolt-on fainead permits the cable
to be reeled-in at an angle without damaging
the cable.

(9-22) High-capacity drum

Courtesy 01 Carco Winch Products

(9-22) Three - roller fairtead

Courtesy of Coico Winch Products

205
 WINCHES 9:13

QUESTIONS TRACTOR MOUNTED

WINCHES
1 List the three methods used to drive trac- 12 On a powershift winch equipped with a
tor mounted winches single lever conVol. the brake will be:
2 Cable may be wound on a drum in one of (a) Spring-applied and spring-released.
two ways and spring-
(b) Hydraulic-applied
(a) Left or right. rr leased.
(b) right or loose (c) Spring-applied and hydraulic-
released.
(c) Forward or backward
(d) Hydraulic-applied and hydraulic-
(d) Overwind of underwind.
released.
3. True or False? Overwind lifts the load so 13 On a direct drive winch with an
that it does not dig in. but on a heavy automatic ratchet and pawl brake. the
load this lifting can cause the tractor to operator may. without releasing the
rear brake.
4 Winches are normally shipped from the reel -in.
(a)
factory set for
(b) reel-out
5 Tractor winches are rated by the do neither.
(c)
(a) Line speed.
14 Besides housing the components and ac-
(b) Size of drum ting as the oil reservoir, what other im-
(c) Line pull in (Kilograms or lbs.). portant function does the winch housing
perform?
(d) (a). (b) and (c) are all correct.
15. What is the function of a fairlead?
6 List the three common types of tractor
winches 16. What are the two main hydraulic com-
ponents that are needed to drive a
7 To shift gears on a sliding gear. tractor hydraulic winch?
mounted winch the
(a) Engine must be slowed down
(b) Tractor's master clutch must be
disengaged.
(c) Tractor must be moving.
(d) Transmission must be in gear.
8. How are gears shifted in a powershift
winch/
9 Both sliding gear and powershift win-
ches depend mainly on a
system for lubrication.
10 What is the main advantage of a
hydraulic winch over a mechanical drive
winch?
11 The Iwo common types of fakes used
on winches are
(a) Hydraulic and air.
(b) Disc and shoe
(c) Band and multi-disc
(d) Band and shoe.

206
9:14 WINCHES

PREVENTIVE MAINTENANCE SERVICE Following is an example of a Preventive Main-

OF TRACTOR MOUNTED WINCHES tenance Table (Hyster Company) for both a
direct drive and a power controlled winch.
SCHEDULED MAINTENANCE CHECKS The table has two schedules. an hourly
schedule and a daily-weekly-monthly
The location of the winch often hinders its schedule. If the winch is operated more than
maintenance. being situated by itself at the eight hours a day the hourly schedule should
back of the tractor. it tends to get forgotten A be followed. If the winch operates eight hours
winch. like any other gear component, or fess a day the daily-weekly-monthly
requires periodic inspection of the unit and oil schedule should be used. The alphabetical
levet checks and oil changes Scheduled oil letters in the table refer to letters in Figures 9-
changes are necessary because after a winch 23 following the table.
has worked a complete shift. its housing is
warm. and when the machine is shut down the
housing is surrounded by cool. night air. This
cool air causes condensation to form in the
housing thereby contaminating the oil. If this
water-contaminated oil is not changed at
regular intervals. damage such as premature
bearing failure or faulty hydraulic control will
Occur.

SAFEGUARD MAINTENANCE AND SERVICE INSPECTION SCHEDULE

SCHEDULE (Hour/Period)

8/ 501 5001 1000/ 2000/

ITEM dy wk 3 mo 6 mo 1 yr QUAN TYPE I PROCEDURE

Oil Level .,/ C 18 Gals SAE 90 MIL-L- Check winch on at level

(Direct Drive) H 210513. for tem. plug 0 on right side of
A peratures above winch Add oil as
N +10°F SAE 10, required at plug E,
G M1L-L-2104B. or Drain oil at plug and°.
E MIL-L-45199 NOTE When checking
Series 3, for tem- winch oil level on win-
peratures +10°F ches mounted on power-
and lower shift tractors slop engine
to obtain correct reading
For winches mounted on
Oil Levet ../ C 20 Gals Automatic Trans- direct drive tractors.
(Power H mission Fluid disengage tractor master
Controlled) A "DEXRON*, for clutch to obtain correct
N temperatures reading
G above -10°F
E SAE 5W. MIL-L- CAUTION. If winch is
2104B. or MIL-L- new or overhauled drain
45199 Series 3, after 50 hours of
for temperatures operation. then flush
10°F and lower refill. replace pressure
fitter element and service
suction filter
-.
Brake and
Transmission
/ Variable Water and or oil Remove plugOand dram
any accumulation of
Compartments water or oil in brake corn.
(Direct Drove/ kartment Replace plug
V). Loosen plug 0 and
drain any accumulation
of water in a heavy film of

207
 WINCHES 9:15

SAFEGUARD MAINTENANCE AND SERVICE INSPECTION SCHEDULE

SCHEDULE (Hour Period)

8' 50 500; 1000' 2000/

ITEM dy wk 3 mo 6 mo 1 yr (WAN TYPE PROCEDURE

Automatic S Mobil Oil high temperature grease

Brake E (Mobil -temp on ratchet ring. pawl
(Optional R Grease #1) assembly. and hub DO
Direct Drive V
Shell Oil NOT completely fill
Only) (Cont I automatic brake assem-
(Derma Grease 1)
0 bly with grease or at-
E Standard Oil tempt to grease bake
(Chevron Indus- through the vent plug.
trial Greases
CAUTION Always install
Texaco (Ther- Oil seals so that vs of
matex EP #1) both seals are pointing
Union 011 inward
(Strona HT-1)
Sun Oil (Suna-
plex 991 EP)
BP Australia
(Energrease
HTB2)

Cable Guide Multi-purpose Lubricate two grease

Rolls Grease fittings()
tOptiOnan
.
Fair lead .. Multi-purpose Lubricate six grease
(Optional) Grease fittings O.

Swiveling Mu Ili-Purpose LubrocM one grease

Drawbar Grease fitting (4).
(Optionaio

Pressure C One Refer to Paris Replace with Hyster az

Filter (Power H Manual proved filter element IS.
Controlled A Coat 0-ring and backup
Only) N ring with multi-purpose
G grease to ensure a leak
E proof seal between frIter
and case

Bevel Gear J Refer to Parts Pry lockwasher tangs

Shaft Locknut Manual of neces- away from IOCknut flats
sary to replace and rettghten locknut to
lockwasher 200 ft-lbs torque Bend
lockwasher tangs over
locknut flats transmission
 9:16 WINCHES

SAFEGUARD MAINTENANCE AND SERVICE INSPECTION SCHEDULE

1

SCHEDULE (Hour:Periodl

8' 50 500' 1000 2000.

ITEM dy wk 3 mo6 mo t yr OUAN TYPE PROCEDURE

Brake and compartment Tighten

Transmission p lug 0 when oil appears.
Compartments
(Direct Drive)
(Cont)

Handling Gear ,' Few SAE 30 Lubricate fulcrum pin

drops connections and other
moving parts at end of
each eight hour shift
Suction Filter S One Peter to Parts Remove suction filter e
(Power Con- E Manual clean thoroughly. and
trolled Only) R reinstall
J
V
CAUTION If winch is new
I
or overhauled. remove
C
Suction filter @after first
E 50 hours Of operition.
clean thoroughly and
reinstall
CAUTION Suction
manifold cover gasket
must be in good con
dition toprevent air
leaks Replace with
Hyster approved gasket

Suction Hose Check both ends of suc

C lamps ton hose to see that hose
(Power Con- clamps are TIGHT
trolled Only) Retighten hose clamps as
necessary

Control Cables N.
Check both ends of each
cable housing to see that
they are securely an
chored Retighten set
screw Uboll. or bracket
bolt as applicable Check
winch end of power con-
trol cable for condition of
roll pin anchor

Automatic S High tempera- Remove automatic brake

Brake E hire grease as assembly° Disassemble
(Optional Fl follows and clean automatic
Direct Drive v Atlantic Rich- brake assembly corn-
0,14 held (Thermo- ponems Pack the two
C grease bearings with a high tem-
perature grease

209
 WINCHES 9:17

Service Instructions (9-23)

7 4.442i
4:00,
4

OIL LEVEL PLUG 0 FILL PLUG

TRANSMISSION
DRAIN PLUG

BRAKE COMPARTMENT
DRAIN PLUG

Courtesy 01 Hyster Company

'210
 WINCHES

Figure (9-24) shows the two filters and their

locations on one model of winch. When
replacing loiters. be sure to clean the
housings thoroughly and install new seal
rings Also check for leaks after start up

Service Instructions

CU

0.RING
BACK-UP RING
FILTER ELEMENT
FILTER CASE-

SUCTION FILTER PRESSURE FILTER

(9.24) SUCTION AND PRESSURE FILTERS, POWER CONTROLLED WINCH

Counftsy of Ilystef Company

211
 WINCHES 9:19

WINCH ADJUSTMENTS 2 Loosen cable rod-end jam nut

DIRECT DRIVE WINCHES 3 Adjust the control cable at the winch con-
trol housing-end until dimension C is ob-
Direct drive winches require periodic (1) tained (distance between the cable-end
tightening of the brake to compensate for nor- and the centerline of the rod-end pin).
mal running wear, and (2) minor adjustments
to the control linkages These adjustments 4 Tighten the jam nut
can be made quickly Below are examples of 5 Push the Brake Handlever to the lull
typical brake and linkage adjustment release position.
procedures
6 Adjust the push-pull cable at the Brake
Hand lever end until dimension D is ob-
tained Tighten jam nut.

W396

(9-25) BRAKE BAND ADJUSTMENT

DIAGRAM DIRECT DRIVE WINCH A= 2-518" 6=15/16 1/8" 0=4.3/4"
couriesy of HyStet Company
19-26} ADJUSTMENT OF BRAKE LINKAGE
To adjust the brake band. proceed as follows DIRECT DRIVE WINCH
(Figure 9-25) Courtesy of Hysier Company
1 Remove the small brake cover from the POWER SHIFT WINCH ADJUSTMENT
loft-hand side of the winch
Power controlled winches require ii) ad-
2 Push the brake handlever to its full justments on mechanical parts such as band
release position brakes (note multi-disc oil controlled brakes
don't need adjusting) and (2) pressure checks
3 Loosen jam nut A and adjustments on the hydraulic system
4 Turn adjusting link B until there is ap- Check service manuals for checks and ad-
proximately 1 32-inch clearance between justments or. individual powershift winches
the brake Land and brake wheel or until Figure 9-27 gives an example of the pressure
there is just enough clearance to prevent checks called for by one manufacturer. These
*brake drag' checks wouid be done with the hydraulic test
5 Tighten jam nut A box described earlier to test crawler brake
and clutch hydraulic controls. If the pressure
6 Replace the brake cover at any point is not within the allowable limits.
the service manual will list the likely causes
and stale what service repairs would have to
To adjust the positioning of the Brake Hand- be done to correct the problem. Always make
lever. proceed as follows (Figure 9-26) these pressure tests to locate the probelm
1 Adjust the brake band. before removing a winch. Its quite likely the
winch may not have to come off.

2.12

,/
9:20 WINCHES

Service instructions
. -
PRESSURE, PSI
PRESSURE BRAKE
PDRT
FORWARD NEUTRAL REVERSE OFF
A 220 (± 101 35 MAX. 220 (-110) 220 f± 5)

8 2201± 10) 2,5 2.5 2.5

C 2.5 2,5 220 (±10) 2.5

D 220 (± 10) 2.5 220 (I 10) 220 (± 101

E 15.30 10.13 15-30 15-30

HYDRAULIC
PUMP PRESSURE
FILTER

CLUTCH

CONTROL 0 BRAKE PRESSURE

PRESSURE LINE

SUCTION MANIFOLD VALVE

WITH SUCTION LINE
FILTER

CONTROL-0-,
CABLE
Ur. FOOT
VALVE
COOLING OIL REVERSE
RELIEF VALVE OIL CLUTCH

FORWARD
OIL CLUTCH
CLUTCH
PRESSURE LINE
OIL
BRAKE
W 3 32c

(9-27) HYDRAULIC SYSTEM PRESSURE CHECKS Come-15v d Hyster Company

REMOVAL AND INSTALLATION OF

TRACTOR MOUNTED WINCHES in winch removal. for example. b )(ore un-
bolting the winch clean the winch and the
To remove a tractor mounted winch follow the rear of the tractor to prevent dirt from entering
step by step procedures outlined in the ser- the winch housing or the tractor transmission
vice manual. Because of their weight. safety is case Another clean work practice is to cover
a main concern when removing winches. The the opening in the rear of the tractor alter
average winch will require a lifting device removing the winch and PTO shalt Typical
with a minimum capacity of 3000 lbs. (1360.8 removal procedures for a Powershift Winch
kg) Cleanliness is also an important concern are given in Figure 9-28.

213
 WINCHES 9:21

Note that removal of the winch's pump from 7 /8 -IN UNC 3000 lbs.
the tractor requires a separate set of x 2 1/2-IN (1360.8 kg)
procedures that will be found in the service (63.50 mm) , MINIMUM
manual CAPSCREWS
(2 RECrp).4
Warning: If winch is to be disassembled the
cable must be removed. Use ex-
treme care wnen removing the
cable-end ferrule from thy drum At4
When the cable lock is resooved.
the cable may spring out with ex-
treme force.

VIEW FROM TOP OF WINCH

INTAKE MANIFOLD STEP 3. Connect lifting device to winch.
Winch will be balanced when connected
as shown.

SUCTION

-*****..
STEP 4. Drain the oil horn the winch.
r.-
SUCTION
PUMP MANIFOLD / COVER
psFsuRe
LINE
CONTROL
CABLE-----, I
GAUGE VI
PRESSURE
LINE

STEP I Remove suction hose from intake

manifold Disconnect pump pressure
line Disconnect gauge pressure ima

CONTROL
VALVE
CONTROL
CABLE PIN
4 RED /
(OUTSIDE)
CAPS CREW
MOUNTING
PAD
4
CABLE STEP 5. Remove suction manifold and cover
BRACKET/ Remove the eight nuts and lockwashers
attaching winch to mounting pad.
ROLL PIN
NOTE When removing the eight nuts. loosen
all nuts slightly. then pry winch away
from mounting pad. Loosen all nuts
STEP 2 Remove access cover plate Remove cot- again and pry winch again. Continue
ter pin and detach blade end of control this sequence until winch can be
cable from control valve spool clevis removed.
Remove capscrew holding cable bracket
to housing. and pull out control cable It
necessary to remove cable bracket,
remove roll pin. Courtesy of Hyster Company

(9-28)

214
 9:22 WINCHES

QUESTIONS MAINTENANCE AND REPAIR Winch installation procedures will be found in

OF TRACTOR MOUNTED WINCHES the service manual. Having installed the
winch and reconnected all the fittings. check
1 True or False/ Because of the heavy the following prior to operating the winch.
weight of winches. safety is a main con-
cern when removing them. 1 No leakage.
Nar 2 Whet is the main source of oil con- 2 Proper oil levels.
tamination on tractor mounted winches/
3 All mounting nuts are tightened to
3 If a winch is operated for less than eight specifications.
hours a day. what maintenance schedule
is recommended?
4 All covers are securely installed.

(a) Hourly maintenance schedule 5 All hydraulic hoses are properly routed to
prevent chafing.
(b) Daily. weekly. monthly schedule
6 The hydraulic pump is primed The pump
(c) Once a year checks are enough
should have been primed during in-
(d) Maintenance only when required stallation by filling the suction hose with
hydraulic oil.
4 Referring to the section taken from a ser-
vice manual on winch maintenance, find HOIST WINCHES FOR CRANES,
the interval at which the suction filter EXCAVATORS AND YARDERS
should be serviced
The history of cable operated machines goes
S True or False Winch band brakes require back a long time. Steam driven, partial swing
no periodic adjustments. shovels were made over 140 years ago.
During the years steam changed to diesel or
6 True or False Multi-disc brakes require electric, the partial swing became a full 360
no periodic adjustment. swing. and new versions of cable machines
7 What instrument is used to test the appeared such as a dragline. a clamshell, a
hydraulic controls on a power shift winch/ hoe.
Until about 1950 nearly all excavator shovels
powered their buckets by cable winding on
and off drums Today cable-drum systems on
excavators have all but disappeared having
been replaced by hydraulically operated
buckets Cable operation. however. is still
widely used for cranes, draglines. clamshells
(Figure 9-30) logging yarders and loaders. and
large electric mine shovels Cable machines
are divided into three main sections (Figure 9-
29)

1 lower works (can be crawler mounted or

truck mounted)
2 upper works (the revolving unit)
3 front end (the attachments)
An even simpler division is to speak of (1) the
basic machine and (2) the convertibility The
basic machine is the lower and upper works.
The convertibility is the front end and is so
named because front ends are convertible
depending on the type of work it is to do a
basic machine can have a crane. a clamshell.
a shovel a dragline mounted to it Note that
not all cable machines are convertible Large
mining shovels. for example. are made for
only one lob and have a permanently mounted
Courtesy 01 EtucyrusEne Co
(9-29) 01 Canada Ltd front end

215
 WINCHES 9:23

Crawler Machine

(9-30)
Courtesy of BucyrusErie Co
of Canada Lid

216
9:24 WINCHES

HOIST WINCHES
Tractor mounted winches. as discussed
earlier. run independently of the main tractor
operations, a single drum is mounted at the
back of the tractor and is used when needed.
On the other hand. hoist winches for cranes,
excavators and yarders are an integral part of
the machine's working machinery. They are
mounted on the upper works and are used to
operate the machines digging, lifting.
shoveling implement (Figure 9-31). Multiple
winches are used on hoist systems. the num-
ber. size and arrangement of the winches
dependent on the make. size and rigging of
the machine

(9-31) Courtesy of BucyrusEno Co.

of Canada Ltd.

217
 WINCHES 9:25

CABLE OPERATION The main line and the haul back lines each
have their own drums and are attached at the
There are a number of cable circuits on a carriage. The main line drum is larger be-
hoist winch system and the cable in each cir- cause it does the heavy work. Logs are at-
cuit is always tight In any given circuit one tached to the carnage by choker cables. and
end of cable is attached to a drurr. while the the main line pulls in the logs on the skyline.
other end is threaded or reeved over a number The logs are released at their desired location
of sheaves and Then :s either (1) fastened to a near the yarder. and the haul back line pulls
part of the working implement (2) returned to the carriage back out again on the skyline to
the drum and fastened at a different location pick up more logs.
of the drum or (3) fastened to a fixed point on
the machine. Through the actions of clutches
and brakes. cable is reeled on and off the
drums to control the movement of the bucket.
boom. load. etc.

CABLE OPERATIONS ON
LOGGING YARDERS
Earlier. it was said that cable was always tight
in hoist winch systems. One exception to this
rule is a logging yarder (Figure 9-32) Yarders
use much larger drums and considerably
more cable than shovels or cranes. and the
cable runs a lot looser.
There are numerous ways yarders can be
rigged. one way is shown in Figure 9-33. Apart
from all the guy lines. this yarder cable system
basically consists of three lines (1) a
stationary line (skyline) on which the carriage iw

runs (2) a line (main line) and (3) a (9

haul-back line The haul-back Irne runs on
sheave blocks that are attached to stumps (,,, 0 . .1.114 Ltd

(9-33)

218
9:26 WINCHES

BASIC WINCH ASSEMBLY

There are a number of differences in hoist
winches such as size. ways of mounting and
activating mechanisms. A common hoist
winch arrangement is Shown in Figure r1-34:
this winch is convertible and can be rigged for
an excavator, hoe. crane, dragline or a clam- FRONT DRUM
she II

SWING PROPEL
CLUTCH GEAR

SWING - PROPEL
CLUTCHES
CLUTCH
and BRAKE

HOR SWING
PROPEL SHAFT

O
1111 I
mt
REAR DRUM

llriil
III
DRUM SHAFT GEAR
TRANS. rr
SHAFT lure CHAIN DRIVE
;; (LOWERING)
iiiIr

arr
CLUTCH & BRAKE
11::1
(LOWERING)
111 1; I.
CHAIN
DRIVE

BOOM HOIST DRUM

CLUTCH
(RAISING)

GEAR DRIVE POWER UNIT

(RAISING)

MULTIPLE STRAND
CHAIN DRIVE (9-34) Courtesy 01 BucyrusEr* Co
01 Canada Ltd

219
 WINCHES 9:27

This basic hoist winch arrangement consists

of two main drum shaft units, one front and
one rear. plus a small hoist drum further to the
rear. The drums are not in line but are parallel.
Mounted crossways near the centre of the
revolving platform. the drums are positioned
to give balance to the whole assembly. The
main drum shaft units are supported by
bearings that rest in precision bored supports
in the machinery deck. Older machines used
bronze or babbitt bearings but modern
machines use anti-friction bearings. The
bearings and supports ensure perfect shaft
alignment and gear fit. Figures 9-35 and 9-36 HOIST DRUM f..:-.2iv;SLY
show two examples of drum shafts resting in
bearing saddles. In Figure 9-35 caps are used
to retain the shalt assembly in place; in Figure
9-36 the upper half of the gear case forms the
bearing cap

INTERMEDIATE HOIST
PINION SHAFT

BEARING
SADDLES

Courtesy of S Maddi Lid (9-35)

HOIST BRAKE

HOIST BRAKE SHAFT

(9-36)

Courtesy of Harnischfeger Corporation mil

220
9:28 WINCHES

DRUM OPERATION
As is seen in Figure 9-37. drums are mounted
on bearings over the drum shafts. and thus a
drum shaft can rotate without turning the
drum. The internal expanding clutch assembly
is attached by a clutch shaft to tte drum shaft.
When the clutch is engaged. the drum shaft
drives the drum: when the clutch is
disengaged the drum shaft and clutch rotate
freely inside the drum An external con-
tracting bard brake encircles the drum.

BRAKE

DRUM

CLUTCH
WIRE ROPE

DRIVER
- OR CLUTCH
BEARING SHAFT

PITCH DIA

SHAFT' 1324

.W.11L71:C73
FIRST WRAP

0-37)
Courtesy of Bucyrus -Erie Co
01 Canada Ltd.

221
 WINCHES 9:29

WINCH POWER TRAIN Engaging a drum clutch will cause the shaft
and drum to turn as a unit, thereby reeling in
Figure 9-38 illustrates a winch power train
The power unit droves the transfer shaft and the cable attached to the drum Releasing the
gears by a drive chain (multiple strand) The clutch puts the arum in a free state and any
small gear on the transfer shaft (dotted lines pull on the cable will turn the drum and cable
A
will be reeled out. The cable and drum can be
behind the large transfer gear) is meshed
the large gear on the rear drum shaft which in stopped and held by the band brake
turn is meshed with the large gear on the front The brake just mentioned works independent
drum shalt When the power unit is running. of the clutch Some winch br4ices on the other
all the parts shown are turning Note that with hand, operate in conjunctibOwith the clutch
this gear arrangement. the front and rear drum When the clutch is engaged the brake
shalt rotations are opoosite automatically releases and. vice versa. when
the clutch is disengaged the brake is applied

FRONT ORUM REAR DRUM

SHAFT GEAR SHAFT GEAR

TRANSFER SHAFT DRIVE CHAIN

and GEARS

(9-38)

222
9:30 WINCHES

A variation on the basic hoist winch assembly

discussed above is to add an additional clutch
to each of the front and rear drum shafts POWER LOWERING
(Figure 9.39). These clutches allow a toad to BOTH DRUMS
be lowered under power.
POWER LOWERING
CLUTCH
(REAR DRUM)
FRONT DRUM

SWING PROPEL
CLUTCH GEAR

SWINGPROPEL
CLUTCHES

HOR. SWING
PROPEL SHAFT

POWER LOWERING
CLUTCH
REAR DRUM
mr (FRONT DRUM)
DRUM SHAFT GEAR
TRANS.
SHAFT
CHAIN DRIVE
(LOWERING)

& BRAKE
CHAIN LOWERING
DRIVE

r...--BOOM HOIST DRUM

CLUTCH ,M11111N
(RAISING)

GEAR DRIVE
(RAISING) POWER UNIT

MULTIPLE STRAND
CHAIN DRIVE
(9-39) Courtesy Of Bucyrus-Erse Co
of Canada Ltd

223
 WINCHES 9:31

Each of the power lowering clutches has a DRUMS AND DRUM LAGGING
sprocket attached to it. This sprocket is con-
nected by a drive chain to a sprocket on the Drums are made in various diameters. line
opposite hoist drum. Notice what happens capacities. and shapes to suit the work a
when a load is lowered under power from the machine must do A yarder drum (Figure 9-40)
front drum: for example. has a high capacity drum be-
cause it uses a lot of cable
1 Remember from the description on winch
power flow that the two drum shafts turn in
opposite directions.
2 When the load is to be lowered from the
front drum. the drum's main clutch is
disengaged. leaving the drum free to
rotate in either direction. Of course. the
drum will be braked until everything is set
for the load to be lowered.
3 Attached to the rear drum shaft. the power
lower clutch for the front drum is
engaged. thus engaging the drive chain
and causing the rear drum shalt to drive
the front drum
4. Since the rear drum shaft turns in a direc-
tion opposite to the front. the front drum
will unwind or lower the load under power.
This procedure would work in reverse to lower
a load from the rear drum.
9:32 WINCHES

The drum working surface or the surface on

which the cable winds is called the drum
lagging Lagging is made in split halves
which are bolted to the drum frame There are
two main types of lagging, grooved lagging
and smooth tapered lagging. Thickness is an
important characteristic in lagging. Because
it increases the drum diameter. a thicker
ti 6°0 00
0 0

0
0
lagging will give faster line speed but the line
will run with less power. On the other hand. a 0 0 0
thinner lagging will give more line power but 0 0
slower line speed. Since lagging is bolted on.
it is convertible. the type of lagging and its SPLIT LAGGING WITH GROOVES
thickness may be changed to suit the par-
ticular tront-end attachment mounted to the (9 -41)
machine Figure 9-41 illustrates types of
tagging.

Y---r.

i
i-_,-_,G 1
I
1.1
'
f

SMOOTH TAPERED LAGGING

POWER LOAD F:c:st CLUTCH SWING CLUTCH
I
LOWERING CLUTCH AND BRAKE Courtesy of Bucyrus -Ene Co.
(9 -41) of Canada Ltd
GROOVED LAGGING

Grooved lagging guides the cable into place Controlled Load Lowering:
and prevents the cable from flattening
Smooth tapered lagging works in the Hoisting Smooth Lagging
following way the cable is anchored to the Lowering Smooth Lagging
small diameter end As the cable is reeled in Following are instructions for installing
each wrap slides on the smooth surface lagging Lagging installation is relatively sim-
towards the narrow diameter end until snug ple provided you observe the following items
against the previous wrap Thus the cable
winds evenly on the drum The types of 1 Clean the boiled surfaces of both the
lagging by different front ends are listed drum and the lagging to remove burrs.
below rust and paint If the mating surfaces are
not luite flat. lightening the bolts will
Magnet Work: result in warping the drum slightly This
Hoisting - Grooved Lagging will produce unequal braking and brake
Pull In Smooth Lagging lining wear
Dragline: 2 Be sure to line up the lagging with the
lubrication fittings so the drum bearings
Hoisting Grooved Lagging may be serviced easily when necessary
Pull In Grooved Lagging
3 Torque the bolts in a cross pattern
Hook and Clamshell:
Holding Smooth Lagging
Closing -- Smooth Lagging
225
 WINCHES 9:33

HOIST WINCH CLUTCHES

BRAKES AND CONTROLS
CLUTCH SHOE
BASIC HOIST WINCH BRAKE
The external contracting band brake has been
used for many years on horst winches and is
still used today. The band is wrapped around
the outside of the brake drum (like a steering
clutch brake) and has lining riveted to its in-
side lace Smaller bands are one piece:
generally. larger bands are two or more sec-
tions bolted together to form the circle. The
sections make the large bands easier to
remove and install. The ends of the bands
have eyes to connect the bands to their ac-
tuating mechanism The complete band brake
and control assembly is attached to the main
frame on the machine. The band brake in
AIR CYLINDER
Figure 9-42 is spring-applied and sir-released.
(APPLY CLUTCH)
(9-43)
BRAKE
Courtesy of Bucyrus-Ene Co
BAND
of Canada Ltd

In a hoist winch the clutch shues and ac-

tuating mechanism are mounted to the clutch
assembly. The clutch assembly is splined or
keyed to the drum shaft and revolves with it.
(9-42) The friction surface that the clutch acts
Courtesy of Bucyrus-Ene Co against is the inside of the brake drum. Clutch
of Canada Ltd shoes have lining material riveted to their
outer surface. The shoes are mounted on the
Various types of controls have been used with clutch assembly so that they pivot at one end
band brakes manual linkage. hydraulic. and move toward the friction surface at the
spring apply air release.* and full air Air other end. Actuation for the shoes is by
controlled is most common today. hydraulic or air cylinders. Once the cylinders
have expanded the shoes the clutch joins the
BASIC HOIST WINCH CLUTCH drum shaft with the cable drum and the Iwo
rotate together
Like the band brake. the expanding shoe
clutch (Figure 9-43) has been used for many Besides expanding shoe clutches. hoist win-
years on hoist winches This clutch works ches use external contracting band clutches
similar to the wheel brake principle of a shoe Contracting band clutches are applied where
contacting a drum The difference. though. is the winch band brake would normally be
that with a brake the shoe must stop the drum. positioned and so the brake has to be moved
whereas with a clutch the shce must join itself to another location These clutches are
by friction to the drum to drive it hydraulic or air actuated
 9:34 WINCHES

Demands for clutches and brakes which will

withstand heavier loads and will require less
maintenance have brought advances in the
basic band brake and expanding or con-
tracting shoe clutch Three examples of these
new clutches are
1 Expanding air tube, multi-disc clutches.
Witchita Clutches (Figure 9-44) as one
common type of these clutches called. FAWICK AIR CLUTCH
are frequently used on logging yarders.
When air is applied to the air tube the
discs and pressure plates are squeezed
together to provide the drive. Not shown in
Figure 9-44 is the drum which surrounds
the clutch assembly. The drum is the
driven member and the hub which is
keyed to a shaft is the drive. A witchita
clutch setup is similar to a steering clutch
used on a crawler.

EXPANDING
AIR TUBES

FRICTION
DISCS

mo

- Courtesy of Fawick Co

-**
v. 4 ,4":$40
3. Magnetic clutches are used where elec-
tric power is available such as on an elec-
41-
sr
tric mining shovel They are called
Magnelorque Clutches (Figure 9-46).

a+ 19,
of
(9-44) WITCHITA AIR CLUTCH Witchila
ca"ne" Company OUTER MEMBER 1,411ER MEMBER
Expanding air tube brakes are also made.
Instead of the one or two discs on air clut-
ches. expanding air tube brakes have a CLUTCH-0.
number of discs SHAFT

2 Air tube clutches used in conjunction with

a contracting band clutch. The air tube PINION
and band assembly surround the drum SLEEVE
When air is applied to the air tubes. the
band shoes are forced towards the drum.
joining the two and providing a drive. (9.46) A SIMPLIFIED VIEW OF
THE MAGNETOROUE
Courtesy of Harnischfeger Corporation Pam

227
I A
 WINCHES 9:35

The clutch shaft and outer magnetorque

member are driven by the main motor.
Since the inner magnetorque member is
separated from the outer member by
bearings. the driven outer magnetorque
can turn without causing the inner mem-
ber to rotate. Only when the inner and
outer members of the magnetorque are
coupled together magnetically, do both
members turn. When the operator places
the hoist controller in the ON position. the
outer driven member coils ate energized.
thus creating a strong magnetic field
which couples the driven outer member to
the inner member. When the inner
magnetorque unit turns. the pinion sleeve
doves the hoist drum
Magnetorque characteristics are such
that a slight slip between the inner and
outer members will cause a large increase
in the amount of torque delivered by the
magnetorque. (9-47) AIR CONTROLS

The repair of a magnetorque unit requires. Counesy of SucyrusEne Co.

in most cases. that the entire unit and of Canada Ltd.
clutch shaft be removed
Two types of valves are used on air controls.
Graduated valves are used where variable
CAB CONTROLS touch control is desired and poppet valves
FOR CLUTCHES AND BRAKES where the response must be fast and im-
mediate
Examples of mechanical and air cab controls
for hoist winch clutches and brakes are HOIST WINCHES ON
shown in Figure 9.47 HYDRAULIC CRANES
Hydraulic hoist winches are used on modern
hydraulic cranes. The power train to operate
the winches is as follows: the crane engine
drives hydraulic pump(s). the pumps generate
the flow and pressure to operate hydraulic
motor(s). and the motors drive the hoist win-
ches. By eliminating the mechanical gear
train, drive and control mechanisms these
hydraulic winches have greatly simplified the
winch assemblies and deck machinery of
mechanical hoist winches. Hydraulic winches
take less space. have simpler controls. and
require fewer adjustments.
Cepending on the manufacturer. hydraulic
hoist winch controls may be direct control or
pilot control. However. the trend on hydraulic
cranes and on other hydraulic machines is
towards pilot controlled valving.

(9-47) MECHANICAL CONTROLS

Courtesy of SucyrusEne Co
of Canada Ltd

( 228
9 :3b WINCHES

Figure 9-48 shows a simplified view of the

main hoist drum on a hydraulic crane Not
shown. but also usually found on the crane.
are auxiliary winches (1 or more) for sup-
plementary hoisting

MAIN HOIST CIRCUIT

MAIN HOIST
CONTROL LEVER

MAIN HOIST
CONTROL LINKAGE

r
CONTROL
VALVES---ta..
I
i
i
L._ 1 r _I

ur
en
COUNTERBALANCE < 9
cr
VALVE i
FREE FALL
CLUTCH CYLINDER HYDRAULIC
MOTOR

FRO PUMP MAIN

HOIST

AUTOMATIC BRAKE
RELEASE CYLINDER

FREE FALL AUTOMATIC BRAKE

VALVE MECHANICAL
BRAKE BAND

(9-48)
Courtesy of BucyrusErse Co
0 Canada Ltd

229
 WINCHES 9:37

QUESTIONS HOIST WINCHES 8. How would the drums on a logging yar-

der differ from those used on a crane or
1 Referrmg to a cable machine. briefly shovel?
state what is meant by
9. What are the two common types of drum
(a) the basic machine lagging?
(b) the convertibility
10. Increasing the thickness of the lagging
2 In contrast with tractor mounted win- increases the drum diameter and causes
ches. the cables on shovel hoist win- the line speed to
ches
(a) decrease.
(a) are smaller
(b) increase.
(b) run tight at all times.
(c) stay the same.
(c) run within a number of closed cir-
cuits 11. True or False? In controlled load raising
and lowering. smooth drum lagging is
(d) are larger used
(e) both (b) and (c) are right.
12. What is the advantage of making large
3 Compared to a cable on a shovel or a brake bands in multiple pieces rather
crane. logging yarder cable is than in one piece?
(a) shorter and runs tighter 13. The most common method for applying
(b) longer and runs looser. hoist winch brakes on today's machines
is by
(c) shorter and runs looser.
(d) longer and runs tighter
14 Give two methods used to apply shoe or
band clutches on winches
4 list three basic ways in which hoist win-
ches differ 15. What advantage do multi-disc expanding
air tube clutches and brakes have over
5 Power to drive a hoist drum is trans- the older designed expanding shoe and
mitted from the drum shaft to the drum contracting band ones.
by
16 The drive and driven members on a
(a) a clutch. machine using magnatorque clutches
(b) a brake
are coupled together by
(c) a combmatior. clutch and brake. (a) friction.
(d) gears (b) heat.
6 What prevents a drum from free wheeling (C) mechanical force.
when the drive is disconnected? (d) magnetic field

(a) clutch brake 17. True or False? Magnetorque clutch

(b) clutch
characteristics are such that a slight in-
crease in slip between the drive and
(c) brake driven members will cause a large
(d) mechanical lock decrease in the torque delivered by the
magnetorque.
7 When power lowering is desired for a
front hoist drum. the power lowering 18. What are the advantages of a
clutch would be mounted on the hydraulically driven hoist winch over a
mechanical hoist winch/
(a) rear drum shaft.
(b) front drum shaft
(c) main drive shalt.
(d) hnrozontal propel shaft
e
/

230
9:38 WINCHES

REMOVAL AND INSTALLATION OF CRANE procedures on specific machines.

EXCAVATOR AND YARDER
HOIST WINCHES ADJUSTMENT ON CONTRACTING
BAND CLUTCH
Removal and installation of a hoist winch is a
relatively straight forward )0b. On most
machines the winch is generally mounted so
that drum shaft assemblies come out as a unit,
as seen in Figure 9-49.

DRAG CLUTCH BOOM HOIST SWING CLUTCH

AND BRAK! BRAKE
19-49)
Courtesy of BucyrusEne Co
of Canada Ltd.
SOME POINTS WHEN REMOVING
AND INSTALLING HOIST
WINCH COMPONENTS
(9-50)
1 Before attempting to remove a drum shaft Adjustment of contracting band clutches is
assembly. place the working implement recommended for smoother application and
controlled by the drum shaft in a safely less maintenance to the air chamber assem-
lowered position and remove the cable bly. To make the adjustment. disengage the
from the drum clutch so that no air is left in the chambers.
2 Tag all hydraulic or air lines that are Then adjust the setscrew (Figure 9-50) to ob-
removed lam a 1/32" clearance. all around. between
the clutch surface and the lining.
3 When the bearing caps and related ac-
cessories have been removed. attach CLUTCH BAND LINERS
slings so that they provide a safe. even
and balanced lift to the shaft assembly. Clutch band liners wear more rapidly on the
fixed end than on the moving end.
SCHEDULED MAINTENANCE CHECKS, -AMERICAN- clutch bands are made with
ADJUSTMENTS AND LUBRICATION both ends alike so that after a period of
ON HOIST WINCHES operation in one position. they may be rever-
sed to give additional service life.
Like most clutches and brakes. hoist winch
clutches and brakes require periodic ad- The clutch band liners should be examined
justment to compensate for normal running periodically for wear. and they shoulu be
wear A clutch slipping under load or a brake renewed before they become thin enough to
not holding the drum indicates that ad- permit the rivets to contact the clutch surface
justments are needed. Tremendous strain is and c,..se scoring. When Innings have to be
applied to these clutches and brakes and renewed. care must be exercised in their in-
allowing slippage to go unchecked will soon stallation to ensure that they are tightly and
lead to the parts failing. smoothly riveted to the band. and that the
bands are liot bent out of shape. After
Typical adjusting procedures are given below. replacing the bands. they must be checked for
one for a contracting band clutch and one for "out-of-round- and 81 necessary. hammered
a contracting band brake Always refer to the back to shape to secure good contact at all
service or operator's manual for the adjusting points.

231
 WINCHES 9:38

EXAMPLE
ADJUSTMENT OF CONTRACTING
BAND BRAKE
(American Hoist and Derrick Co.)

MAIN HOIST BRAKE ADJUSTMENT

BRAKES ARE SHOWN IN

RELEASED POSITION

REACH
ROD

\, ,
1 8" (318 mm) .,..6

(9.51) Courtesy of American Hoist and Derrick Co

1 With new or newly relined band set gap on 7 Adjust lifter spring -E- so that It has am-
metal portion of band at point "B" to 1- ple lifting force to disengage band when
1/2" (381 cm) brake IS released, but be very careful that
the spring IS not lightened to the point
2 Disconnect spring loaded air brakes by where there is no recoil left in It.
removing pin "G" from clevis "L"
8. Test with load and make final and all
3 Adjust pedal to operators preference by future adjustments at split "B".
extending or retracting reach rod. General
setting is so the full line pull may be held 9 Adjust the devises "L" on the brake
in the last notch of the pedal latch chamber rods until they can be connected
to the brake pedal linkage. The hoist
4 Set lifter "A" at dead end with brake set brake pedal and brake valve (on lever
030" ( 762 mm) clearance. stand) must be released (air in brake).
5 Make sure that guide "C" is free of both Allow 1/8" (3 18 mm) clearance between
band and guide bars on band. the back of brake chamber and the nut
and washers on the brake chamber rod.
6 Set 1:Itsr "D" at live end with brake set to
060" (1 524 mm) clearance.

232
9:40 WINCHES

LUBRICATION FOR HOIST WINCHES

Lubrication for hoist winches will be found in
service manuals. The more mechanical the
hoist machinery the more lubrication points it
will have Most of the bearings for deck
machinery, operating levers. shafts. bell
cranks. etc . have grease fittings tapped direc-
tly into the bearings Location of these fittings
as w II as other points on the deck machinery
that require lubrication will be shown in the
manual on lube carts. A chart may show in-
dividual drum shafts or it may show a com-
Mete deck plan. Some charts also include the
type of lubricant and lubrication interval
Examples of lube charts are shown in Figure
9-52 and 9.53

MAIN & AUXILIARY HOIST DRUM ASSEMBLY

TO LURE
THIS
FITTING.
SHAFT & DRUM BEARINGS
REMOVE
USE ITEM #2-6 MONTHS
FRONT I:
CLUTCH
GUARD

THESE FITTINGS ARE

REACHED THROUGH
HOLES IN LAGGINGS

(9-52)

Courtesy of Amencan Hoist

and Derrick Co

233
 WINCHES 9:41

BOOM HOIST CLUTCH SHAFT ASSEMBLY

LUBRICATION

BOOM CLUTCH
BEARING
ITEM #2 SHAFT BEARINGS
6 MONTHS ITEM #2 DAILY

Courtesy of American Hoist

and Derrick Co
(9-52)

MAIN HOIST CLUTCH ASSEMBLY THIRD DRUM CLUTCH ASSEMBLY

CLUTCH LEVER PINS

ITEM #8 WEEKLY
Courtesy of American Hoist
and Derrsck Co
(9-52)

234
 9:42 WINCHES

EXCAVATOR LUBRICATION (HOIST MACHINERY

LUBE POINTS ARE STARRED (* })

THE LUBRICATION RECOMMENDED

IS BASED ON OPERATION OF THE
MACHINE EIGHT HOURS EACH DAY,
LUBRICATE MOTORS AND FIVE DAYS PER WEEK LUBRICATION
GENERATORS ACCORDING SCHEDULES SHOULD BE ADJUSTED ON
HOIST GEAR CASE
TO INSTRUCTIONS ON 80 GALLONS THIS BASIS.
MOTOR OR GENERATOR. GO
SYMBOLS
MPG - MULTIPURPOSE GREASE
HOIST DRUM SEALS GO GEAR OIL
MAGNETORQUE 2 POINTS SWING GEAR GL - GEAR LUBRICANT
SEALS MO MOTOR OIL
EVERY 200 HOURS CASE RH
2 POINTS MPG 40 GALLONS 10 - INSULATING OIL
EVERY 200 HOURS GO
MPG

WORM SHAFT SEAL

i POINT EVERY 200 HOURS
MPG
COUPLINGS
2000 HOURS
MPG

40 HOUkS
RACK
PINIONS
GL

AIR COMPRESSOR
CHECK EVERY 40 HOURS DIPPER TRIP
DRAIN AND REFILL I POINT - DRUM BEARING
EVERY 1000 HOURS (SEE MOTOR NAMEPLATE)
MO 1 POINT - RING GEAR
SWING GEAR EVERY 120 HOURS
CASE LH MPG
MAIN OIL CONTACTORS 40 GALLONS
CHECK EVERY 1000 HOURS GO
45 GALLONS
10

(9 :>3)
Courtesy of Harnischfeger Corporation P&H

235
 WINCHES 9:43

QUESTIONS MAINTENANCE OF
HOIST WINCHES
1 What is the first step that must be done
before removing a hoist winch drum and
shaft assembly?
2 An indication that adjustments to the
clutch and brakes on a hoist winch are
required is that the winch
(a) operates slowly.
(b) applies and releases with difficulty.
(c) will not release
(d) slips under load.
3. A typical adjustment procedure for a shoe
clutch requires that the adjustment be
made so that the clearance between the
shoes and the drum is approximately:
(a) 1/4"
(b) 1/32"
(c) 1/64"
(d) 1/8"
4. True or False? Hoist winch assemblies
should be lubricated on a "whenever
required'. basis
5. Referring to the excavator lubrication
chart (Figure 9-53). find at what interval
the hoist drum seals are grea...ed and what
type of grease is used.

236
9:44 WINCHES

WIRE ROPE
Wire rope comes in a number of diameters.
cross sectional constructions and strengths It
has many uses in the heavy duly mechanical
field. a few of which are shown in Figure 9-54
and 9-55.

(9-54) CRANE OR CLAMSHELL

BOOM PENDANTS Th4

BOOM LINE
HOLDING LINE

CLDSING LINE

r
., ,
,A
.... TAG LINE

BOOM LINETh
HOIST LINE
CROWD LINE
17

RETRACT LIN
TRIP LINE
''Apr
.1/1
t
eg -

(9-54) POWER ;HOVEL (EXCAVATOR)

237
 WINCHES 9:45

DRAGLINE

BOOM PENDANTS

Courtesy of Marlin and Black

(9-54) Wire Ropes Ltd

4 PART BRIDLE SLING

WIRE ROPE
SLING

Length
of
Sling
(SL)

(9-54)

Courtesy of Martin and Black

Wire Ropes Lid

238
WINCHES

LOGGING

(9.55) Courtesy of S Madill Lld

 WINCHES 9:47

The parts of a wire rope are the wire, the

strand. and the core (Figure 9-56).

(9-56)
CORE WIRE STRAND

The cross section of a common six strand wire Courtesy of Marten and Black
rope is shown in Figure 9-57. Wire Ropes Ltd

(9-57)
Courtesy o1 hilatten and Black
Wire Ropes Ltd

MEASURING A WIRE ROPE

The diameter of a wire rope is identical to that
of a circle which would surround the rope. To
gauge a rope be sure that the faces of the
calipers are in contact with the crowns of two
opposite strands and not in contact with four
strands (Figure 9-58). To be certain that the
calipers are in the correct position rotate
them around the rope: the greatest
measurement is the correct size.
Nato: After a rope has been in use it is INCORRECT
sometimes possible to get two
"correct" readings of its size that vary (9-58)
considerably. Differer t readings can
occur when the rope has lost its shape
due to crushing or when there is
corrosion or core damage at in- Courtesy of Marten and Black
termittent points along the rope. Were Ropes Ltd

240
9:48 WINCHES

CORES WIRES
The core in a wire rope is the central section Wire on a wire rope varies in its diameter and
around which the strands are laid. Cores can the type of steel d is made of The steel will
be made of fiber or steel. range from having great strength to having
less strength but more durability or resistance
Fiber Core to fatigue. Note that it Is wrong to think that
Fiber cores can be made of vegetable the rope with the strongest steel is
fibers such as manila. lute or sisal. necessarily going to be the best for every lob
although increasing use Is being made of For example on a given lob. a rope made with
manmade fibers. Polypropylene. for exam- a ductile flexible steel may out perform and
ple. offers the advantage of better out last a rope made of a steel with a higher
resistance to rotting. drying out and other breaking strength.
forms of deterioration than natural fibers. When corrosive conditions warrant rope
The main function of a fiber core is to protection over and above normal lubrication.
cushion the steel strands during wire Is galvanized.
operation. Also because the core is
usually impregnated with lubricant before STRANDS
manufacture. it acts as an internal CHARACTERISTICS OF STRANDS
lubricator during the operation of the
rope. Fiber core are the most flexible wire t Strands are classified by the number of
ropes. strands on a rope and the number of wires
per strand
2. Steel Cores
NO. OF WIRES PER
A steel core is usually a small separate or CLASSIFICATION STRANDS STRAND
independent wire rope referred to as an 6 7 6 7
IWRC An IWRC normally has a core and 6 19 6 16 to 26
six strands (Figure 9-59). A wire strand 6 37 27 to
can also be used as a steel core on fairly 8- 19 It, to 26
non flexible rope. such as guy wires
(Figure 9-59)

A steel core adds strength (7,4%

minimum) and provides resistance to
crushing. Additional strength is not the
only reason for specifying a steel core.
Where a steel core is required excessive
heal in the operation of a rope could
cause charring of the fiber. An IWRC is
also essential (or maximum performance
on such applications as shovel hoist lines.
draglines. etc.

19 wire Wend 6x25

IWRC
(9-59)

Courtesy ot Marpn and oink

wire Ropes Ltd
241
 WINCHES 9:49

2 The wires on a strand have different cross

sectional patterns. three of the most com-
mon are shown in Figure 9-60.

SEALE CONSTRUCTION
One layer of wires is laid over an equal number of smaller wires. with the
same length and direction of lay. The wires in the outer layer are supported
in the valleys between the wires of the inner layers

,11il

FILLER CONSTRUCTION
In this construction. the outer wires are supported by half their number of
1
main inner wires with an equal number of small filler wires.

WARRINGTON SEALE
A strand construction in which one laver of wires is composed of alternat-
ing large and small wires. The length of lay and number of wires in each
layer. are equal.

In larger Size wire ropes. more than one of the above basic constructions may be integrated in a
single strand.
(9-60) Courtesy of Marlin and Black
Wire Ropes Ltd
3 Most wire rope today is preformed. that is.
each wire and strand is preset to the exact
helical shape it will take in the finished
rope A preformed rope won't unravel
when cut Preformed wire rope is more
flexible. lasts longer. and is easier to
splice (F1; 3-61)

242
9:50 WINCHES

BALANCED PREFORMED NON-PREFORMED

rl
Courtesy of Martrn and Black
Wire Ropes 1.1d
(9-61)

4. Lays of Wire Rope

(Martin and Black Manual). The term "lay"
has two meanings in reference to wire
rope.

(a) When used to describe the direction

of rotation of wires the term is usually
applied to two basic lays: (9-62)
Regular Lay is applied where the
wires turn in the opposite direction to REGULAR LAY LANGS LAY
that of the strands in the rope. The Courtesy of Marton and Black
outer wires of the strands are parallel Wire Ropes Lid
to the rope axis (Figure 9-62).
The advantages and disadvantages
In Langs Lay, the wires in each are.
strand are laid in the same direction
as the strands of the rope (Figure 9- Regular Lay: Greater resistance to
62) The outer wires of the strands are crushing on drums than Langs Lay; it
at an angle to the rope axis and much should always be used on a single
Kiger lengths of the individual wires part Isle. or when one end is free to
are e, posed rotate.

243
 WINCHES 9:51

Lange Lay: More flexible and offers being good maintenance policy. periodic
greater resistance to abrasion than inspection of all wire rope in critical lifting
Regular Lay ropes. Only applications service is required by government
where both ends are fixed are regulations. and records of the inspection
suitable for Langs Lay rope. it should must be kept. Wire rope should be
not be used with a swivel terminal. replaced when a qualified inspector feels
Langs Lay cable is used on power it can no longer safely do the job it was in-
shovels and draglines and for mine tended to do.
hoisting.
Points on Inspecting Wire Rope
Right or left lay is determined by the
direction in which the strands are (a) When checking wire rope. the rope
laid in the rope The strands in a left should not be in motion or should not
lay rope (Figure 9-63) run to the left be supporting a load: it should have
from the top to the bottom (which no stress on it.
ever way you look at the rope). (b) All rope used in vertical lifting ser-
Strands in a right lay rope (Figure 9- vice should be checked and each
63) run to the right from top to bot- rope must be considered separately.
tom The vast majority of ropes are
right-regular lay. (c) Inspections should be done weekly.
(d) There are certain points along any
given rope which should receive
more attention than others. since
some areas will usually be subjected
to greater internal stresses. or to
Right Lay greater external forces and hazards.
(9-63) Although different types of cable ap-
plications will have different critical
points (Figure 9-64) some common
ones are:
Pick-up Points These are sections
Left Lay of rope which are repeatedly placed
under stress when the intitial load is
applied. Examples are the sections of
rope in contact with sheaves.
(b) The term lay is also used as a rope End Attachments Al each end of
measurement. One rope lay is the the rope. two things must be in-
length along the rope which one spected. the fitting that is attached to
strand takes to make one complete the rope. or to which the rope is at-
spiral around the core. tached. and the condition of the rope
itself where it enters the attachment.

(9-63) Courtesy of Leschen Wire Rope Co

Abuse Points Frequently. ropes
are subjected to abnormal scuffing
WIRE ROPE INSPECTION and scraping such as where the rope
contacts cross-members of a room.
Eventually all wire rope deteriorates to a Look for bright or shiny spots on the
point where it is no longer serviceable or rope.
safe. Regular inspections. therefore. are
necessary to ensure that the rope :s in ac-
ceptable working condition. Besides

244
9:52 WINCHES

(9-64) CABLE CRITICAL POINTS

5 An inspection of wire rope should include EXTERNAL ROPE DAMAGE

checks for the conditions below (Figure 9- OR ABUSE
6r.). If any of these conditions are found.
the strength of the rope is in question and Rope Abuse Kinking. drum crushing, bird
the possibility of replacing it should be caged and trapped rope are shown in Figure 9-
considered. 65.

An "OPEN KINK An "OPEN KINK" after straightening fume

misplaced wires and strands}
(9-65) Courtesy of Marten and Black
Wire Ropes Ltd

245
 WINCHES 9:53

A rope with snagged wires resulting from "DRUM A BIRD CAGE which haS been forced through a
CRUSHING" tight sheave
(9-65) Courtesy of aotatun and Black (9-65)
Wire Rope Ltd

One manufacturer recommends that any

broken wires at the dead end of a cable
should be cause for cutting off a section.
preferrably at least three feet beyond the
broken wires Refasten or re-socket the rope.
A rope that has been 'TRAPPED after lumping Also check for:
oft a sheave
1. The core showing through more than one
pair of strands.
Corrosion look for serious corrosion in the
rope 2 Evidence of improper lubrication of the
rope Evidence of the rope overheating or
End Point of Cable Check (1) for broken coming in contact with an electrical cir-
wires where the rope is attached to the fixture cuit.
(Figure 9-66) and (2) that the fixture is firmly
attached to the rope or that the rope is firmly 3. The amount of wear on outer wires. The
secured to the drum. Operating Engineer's Manual recom-
mends that wire rope should be replaced
when the wires in the crown of the strand
are worn to lees than 60% of their original
diameter (Figure 9-67).

ti

--1.41
(9-67) Rope whiCh has been worn due to ABRASION
(Note even wear around the strands).
Courtesy of Martin and Black
(9-66) Wire Ropes Ltd

246
 9:54 WINCHES

DIAMETER MEASUREMENT AND BROKEN Note that flexing a rope can often reveal
WIRE COUNT broken wires that may not be visible when the
rope is straight (Figure 9-69)
Reduction in Rope Diameter: Measure the
rope diameter and compare the reading with
the Original diameter. A marked decrease can
indicate a serious weakening of the rope
Broken Wire Count: Broken wires are
probably the most common sign of rope
deterioration because it's normal for running
,t`
rope to break wires near the end of its ser-
viceable life. Two broken wire counts are
made over one lay length of rope.
1 Count the number of broken wires In one
rope lay length on the worst section of (9.69)
rope It is important that the worst section
Courtesy of Martin and Black
be used for the count because that is the Wire Ropes L1C
weakest section of rope Note that this
count totals the broken wires in all the
strands in the one lay length.
2 Count the number of broken wires in one
strand in the lay length. Again. the worst
strand or the strand with the most broken
wires should be counted.
The number of broken wires permitted per
lay or per strand per lay is specified ac-
cording to the rope size. For example. the
Operating Engineer's Manual. using a
count for total broken strands per lay.
recommends that rope should be replaced
when
(a) three broken wires are found in one
0 lay of 6 x 7 wire rope
(b) six broken wires are found in one lay
of 6 x 19 wire rope.
LOOKING FOn BROKEN WIRES
A close search should be made for broken
wires (Figure 9-68) With a sharp awl, pick and
probe between wires and strands lifting any
wires which appear loose or move ex-
cessively.

(9-68) BROKEN WIRES

Courtesy of Martin and Black
Wire Ropes Lid
247

- ---.-
 WINCHES 9:55

Records of inspections, as mentioned earlier. must be kept An example of a Rope In,pection record
sheet is given below Diameter Loss and the number of wire breaks would be recorded and com-
pared to allowa'...ie tolerances

Rope Condition

No. of
No. of wire
Rope Date of wire breaks
descrip- Inspec- Nom breaks In one
lion tion & dia, in. Loss in one strand
(hoist, Date of Inspec- (when Current of rope of one
swing Instal- tor's new) dia, dia, in. lay lay Date of
line, etc.) lation Initials Col 1 In. Col 2 Cot 3 Col 4 Removal

INSPEC. DRUMS AND SHEAVES LUBRICATING WIRE ROPE

The general condition of drums and sheaves Wire rope has moving parts. Each time a rope
should also be checked A thorough checking bends over a sheave or straightens from a
of sheaves involves checking each sheave slack position. many strands move or slide
with a groove gauge The drum should be ob- against each other. Therefore to prevent rope
served in operation to check the drum wind wires from wearing lubrication is rh. essary.
An equally important reason for lubricating
In summary a recommended order of rope is to prevent the wires from corroding.
procedures for carrying out a wire rope in- Wire rope should not be allowed to rust: rusty
spection is rope is dangerous as there is no known
I Measure diameter. Record. method of inspecting it to determine its
rema .zing strength.
2 Count broken wires (a) in one lay. (b) in
one strand in one lay. Record No set rule can be given concerning the
frequency of lubrication The frequency will
3 Check rope end points depend on the conditions to which the rope is
4 inspect the rope end to end for external subjected The severity of the duty and the
damage and abuse. Try to find the cause degree of corrosiveness will have to serve as
an .ndex in determining the need for
of damage and see if it can be prevented
from happening again. lubrication Proper luhricant should be used
The lubricant should be thin enough to
5 Inspect le sheaves and drums penetrate the strands to the core. but not so
thin that it will run off the rope. The best
lubricant is a fairly thick, semi-plastic type.
which is applied hot. in a thinned condition.
This type of lubricant will penetrate while hot
and then cool to form a plastic filler and
coating. which will resist the penetration of
water

248
9:56 WRICHES

Three methods of applying lubricant to wire

rope are illustrated in Figure 9-70. Each has
its advdrilages. and no single method is
recommended in preference to the others The
most convenient method should be used
LUBRICANT (9-70)

SPLIT BOX METHOD

SPLIT BOX METHOD-funnel shaped

tax fitted with burlap or wiper at outlet
end.

BURLAP Counesy of HarniShteger Corporation P.51-1

WRAPPER

POUR.ON METHOD
14,
THE POURON METHOD-oil should be
hot, yet adhesive. Always hold the
wiping swab behold the sheave.

AM.

BATH METHOD

BATH METHOD-for applying heavier-

bodied lubricant at high temperature.
' Gas burners or steam heat may be used
to maintain temperature of lubricant.
Rope should rim through slowly.

CUTTING WIRE ROPE ficient. On non-preformed wire ropes less than

7/8 inch in diameter. two seizings on each
When wire rope is to be cut. swings should side are recommended. On non-preformed
be placed on each side of the cut line to wire ropes over 7/8 inch in diameter. three
prevent underlaying of the strands. A seizing seizings are recommended.
IS shown in Figure 9-71. The se:zing on the left
is loose to show how it's wrapped On the Three basic methods are recommended for
right is the tightened seizing cutting wire rope:
1. Abrasive cutting tools. A suitable abrasive
ROPE WOULD BE CUT HERE cutting machine will cut cable.
2. Shearing tools. Wire cutters can be used
to cut through smaller ropes. while special
blade-action tools and a hammer are used
for larger sizes.
3. Flame. Welding equipment can be used to
(9-71) burn cuts through wire rope. Flame cut-
ting isn't recommended if the wire strands
need to be free after the cut as the torch
On preformed wire rope. one seizing on each tends to weld the strands together.
side of the cut is usually considered to be suf-

249
 WINCHES 9:57

STORING WIRE ROPE REELS Another type of clamp is the Double Saddle or
Fist Grip clamp (Figure 9-74). These clamps
Wire rope reels should be stored in a covered are better than U-bolts because they can't be
area if possible and on pallets or timbers Installed incorrectly (i.e., they are the same on
both ends) and they cause less damage to the
CLAMPS AND SHEAVES wire rope. Also, a fist grip loop requires less
rope turnback than a U-bolt loop and con-
WIRE ROPE CLAMPS sequently fewer clamps are needed. In spite
Clamps are used to of the advantages of Double Saddle clamps.
U-bolts still seem to be the most common
Form a loop in a rope in order to attach clamp used, perhaps because they are
the rope to a fixture (Figure 9-72). cheaper and more readily available.

CLAMPS
METAL EYE

(9-72)
Courtesy of Marton and Black
Wire Ropes Lid

2. Form loops to attach two ropes together.

The metal eyes are connected together.
The U-Boll in Figure 9-73 is a very common
type of clamp used with wire rope. Properly at-
tached U-Bolts are fairly efficient clamps: im-
properly attached they are unsafe.

(9-74) DOUBLE SADDLE CLAMP

Courtesy of Crosby Group

Division 01 American HolSO and Derrick Co

(9-73) U-BOLT
Courtesy of Crosby Group
Division of American Float and Derrick

250
9:58 WINCHES

SHEAVES II you need to match a sheave to a rope first

A sheave (pronounced shiv) is a wheel with a
measure the sheave with a groove gauge
(Figure 9-77) Knowing the sheave size you
grooved circumference around which a rope can check with a rope manufacturing com-
turns A clothesline pulley is a sheave.
Sheaves used on heavy duty machines are pany the rope size suitable for it.
made of steel and either turn on or with an
axle Tnese sheaves have either a bronze
sleeve bearing or anti-friction bearings and
generally have grease fitting(s) that must be
lubricated (Figure 9-75).

7//7. I V/74

(9-75)
(9 -77) GROOVE
SHEAVE CROSS SECTION
GAUGE
Courtesy of Martin and Black
Wire Ropes Ltd
Courtesy 0 Marton and Black
Wire Rope Lid

The groove on a sheave is made to fit a par-

ticular size rope One of the major causes of
premature rope failure is having sheaves and
ropes incorrectly matched. A groove that is
too small will pinch and distort a rope.
wearing or damaging one or both rope sides
Too large a groove gives the rope no lateral
support which can cause the rope to flatten
and the wires and strands to be displaced
(Figure 9-76)

Courtesy of Malin and Black

Wore Ropes Ltd
GROOVE GROOVE TOO GROOVE TOO
CORRECT (9 -76) LARGE SMALL

251
 WINCHES 9:59

Bending over sheaves is a factor that affects

wire rope life. As the rope bends over a
sheave or winds on and off a winch drum.
especially under load, it is subjected to added
3-
stress. The less bend the rope IS forced to
make the less strain imposed on the rope. The
"Diameter- of the sheave, therefore. is also
important to rope operation. Wire rope life in-
creases as the ratio of sheave diameter to
rope diameter increases A chart is given in
Figure 9-78 showing the minimum sheave
diameter size to rope diameter size
(9-78)

MINIMUM DIAMETERS:
A Sheave or Drum of too small diameter will hasten "fatigue" in any wire
rope. The following table gives recommended minimum sheave tread
diameters:
,..
For 6 x 7 construction 42 x rope diameter
For 6 x 25 Flattened Strand construction 36 x rope diameter
i: For 18 x 7 construction 34 x rope diameter
is For 6 x 19 Seale 30 x rope diameter
,.
For 6 x 21 Filler 28 x rope diameter
For 6 x 25 Filler 25 x rope diameter
=O
(13

(a For 6 x 26 construction 26 x rope diameter

For 6 x 31 construction 24 x rope diameter
For 6 x 36 construction 22 x rope diameter
For 8 x 19 Seale 21 x rope diameter
For 6 x 41 construction 20 x rope diameter
For 6 x 43
. 21 x rope diameter
For 8 x 25 " 18 x rope diameter

Courtesy of Marton and Slack

Wore Ropes Ltd
Figure 9-79 illustrates sheave applications on
a power shovel.

SHEAVES

BOOM LINE
HOIST LINE

SHEAVES

RETRACT LINE
TRIP LINE
'"
.
$
A
1 o
. t.
S

Err
Courtesy of Bucyrus -Ene Co
(9.79) of Canada lid

252
9:60 WINCHES

Multiple sheaves are used on some machines Part 1 of the illustration shows the beginning
to gain mechanical advantage Increasing the of a kink At this stage. no harm will be done if
number of lines and sheaves reduces the the loop is immediately thrown out to prevent
speed of the load being Idled but increases further kinking.
the amount of load that can be lifted. The
shovel in Figure 9-30 has a two part line to the Part 2 of the illustration shows the effect of
bucket giving d a mechanical advantage of the application of a load to a kinked line. The
two In other words. the bucket can lift twice rope has been seriously strained and is no
as much as it could with one line to it longer safe for maximum service.
Part 3 shows the condition of the rope after
REMOVING AND INSTALLING WIRE ROPE the kink has been straightened out. Strands
and wires are out of position. This creates
TAKING WIRE FROM A COIL unequal tension and strain and will cause ex-
When unreeling wire rope. it is important that cessive additional wear on the damaged
the coil or reel rotate as the rope unwinds. If areas.
the coil or reel does not rotate. the wire will be Figure 9-81 shows the correct methods for
twisted as it is uncoiled. and kinking will unreeling ropes from coils or reels.
result
Kinking is caused by the rope taking a spiral
shape as the result of unnatural twist in the
rope Figure 9-80 shows the progressive
stages of a kink. and the end result

1
WRONG WAY RIGHT WAY

55==z7ssz WRONG WAY RIGHT WAY

3 WHEN UNREELING OR UNCOILING WIRE ROPE
DO NOT ALLOW ROPE TO FORM A LOOP IF
LOOPS ARE FORMED KINKING WILL RESULT
(9-80) KINKING OF WIRE ROPE
(9-81) UNREELING WIRE ROPE
Courtesy of Harnischfeger Corporation P&H

Another acceptable method of reeling rope off

a reel is to place a shaft through the center of
the reel and support the shaft so the reel can
revolve as the rope is pullei off. If this method
Is used. the reel should not be allowed to
revolve so rapidly that it throws rope oil reel
the rope off slowly.

253
 WINCHES 9:61

REWINDING ROPE
When unwinding rope from its storage reel to
another reel or a drum. the rope must be
reeved from the top of one reel to the top of
the other. It is also acceptable for a.) un-
derwind to reel from the bottom of one reel to
the bottom of the other reel or drum. By
following either of these procedures. you will
avoid twisting the rope (Figure 9-82).

RIGHT

WRONG Courtesy of Martin and Black

were Ropes Ltd
(9-82)

WINDING ROPE ON A DRUM

On grooved drums the cable will be laid in the
correct position by the grooves. but on
smooth faced drums. such as on a tractor
mounted winch. attention must be given to
getting an even lay on the first layer. When in-
stalling a new line on a tractor mounted
winch. attach the line to the drum in the over-
wind or underwind position. whichever the
winch is set up for (most mounted winches are
set for overwind). Then attach the other end to
a firm tail-hold and winch the machine back-
wards to load the drum. Watch that the first
layer winds tight and snug. It the first layer is
wound correctly. the rest of the cable should
wind evenly on the drum. Caution: Keep
hands clear of winding cable.

254
9:62 WINCHES

Figure 9-83 illustrates the correct way to at-

tach left and right lay rope to a drum that has
provision for attaching the cable to either side
and that can be overwound or underwound.
Note the point of view is from behind the
drum.

PROPER WIND '3 FOR PROPER WINDING FOR

RIGHT L LEFT LAY
(Use right r,...rod) (Use left hand)

OVERWIND UNDERWIND OVERWIND UNDERWIND

Left to Right Right to Left Right to Left Lett to Right
(9-83) Courtesy of Martin and Black
Wire Ropes Ltd

ATTACHING U-BOLTS
U-Bolts must be attached in the right numbers
and in the right sequence to the correct side
of the cable.
A
THE RIGHT WAY

B
THE WRONG WAY

I.! 1111111

(9-84)
Courtesy of Martin and Black
Wire Ropes Ltd
In Figure 9-84. A the right way. the saddle of
all the clips bears on the five part of the rope
and the U-bolt bears on the dead part. When
the U-bolt bears on the live side as in Figure
9.84, B the wrong way. there is a possibility of
the rope being kinked or deformed
255
 WINCHES 9:63

The table in Figure 9-85 shows the correct

number of clips to be used for each size of
rope with the proper spacing between them.

SPACING CENTER
DIAMETER OF ROPE NUMBER OF CLIPS
TO CENTER

2 23.4"
2 23/4"
2 3"
2 33/4"
3 VA"
vii4" 3 4"
3 4"
4
4W'
4
4 6"
5
7"
5 7PAr
6
1'2 6 9"
91,4
6
6 10%"
2" 7 12"

Alter the wad is appised to the rope. lessen the tension and retighten the clips This will compensate for
the natural diameter reduction of the rope under load
(9-85) Courtesy of Martin and Black
The cable clamps should be put on in a set Wire Ropes Ltd
sequence Alter selecttng the number of
clamps according to the rope size and
figuring out how long the dead end of the
rope must be 10 give correct spacing between
the clamps. attach the damps in the following
order (Figure 9-85)
Step I Attach the clip that is farthest from
the eye Tighten it to the recom-
mended torque.
Step 2 Attach the Clip that is closest to the
eye Firm it. but do not tighten.
Step 3 Attach all other Clips. equally
spaced. between the first two Clips.
Firm, but do not tighten them.
Step 4 Apply tension to the rope at the eye
and tighten all clips that haven't
been tightened. The torque on the
clips should be checked after the
rope has been operated Courtesy of Martin and Black
(9-85) Wire Ropes Lid

ATTACH ATTACH ATTACH

SECOND THIRD FIRST

256
9:64 WINCHES

ATTACHING DOUBLE SADDLE CLIPS

(FIST GRIP CLIPS)
Since double saddle clips are the same on
both ends they can't be put on incorrectly.
Fewer of these clips are needed than U- bolts;
check the manufacturers recommendation for
LINE
the number of bolts per cable size. The LOCATIONS
sequence of attaching the clips would be the
same as for U-bolts. DRUM

REEVING WIRE ROPE

Reeving means installing or rigging wire rope
to a machine attaching the rope to the
drum, passing rope over sheaves, and
generally arranging the cable into its
operating circuit. Figure 9-86 shows the
reeving on a large mining shovel. Since this
particular machine has a fixed boom angle
and a power operated crowd, it has only the
hoist drum circuit to reeve.
Courtesy .31 Harnischfeger Corporation pm

))*
TWO BOOM
CABLE (2) POINT SHEAVES
HOIST DRUM CENTER DRUM
CABLE ANCHORS
SIDE CABLE
EQUALIZER ANCHORS
SHEAVES

% i\dCABLE(1)

LOWER
SHEAVE
WW UPPER
SHEAVE

(9-86) HOIST REEVING DIAGRAM

(9-87)
This cable system uses two cables of identical
length and size The cables are attached one
to either side of the drum. Each cable is
passed over the boom point sheaves. down
around the lower or bucket sheave. back over
another boom point sheave, returning to the
hoist drum near its center. Cable is therefore
attached in four places to the drum. and when
the line is winding. the two cables can appear
to be four Figure 9-87 shows the locations
where the cable is attached to the drum. and
the anchors by which it is attached. Note the
lour bets of grooves the line runs in: the two
cables on the outside wind towards the inside
whereas the two central lines wind towards
the outside.

257
 WINCHES 9:65

The cable system described above would be

used on such a shovel as the one n Figure 9-
88 Note that in this side view, only one boom
point sheave can be seen and only one of the
four drumlines is visible.

Courtesy of Harnischfeger Corporation P&H

BOOM POINT
(9-88)

An example of reeving for a boom is shown in

Figure 9.89 41-----BOOM
NOTE THIS PENDANT LENGTH TO SUIT
CENTER SECTION OF BOOM

PENDANT YOKE

ROPE (9-89)
ANCHOR

A-FRAME
SHEAVES Courtesy of Bucyrus -Erne Co
of Canada Ltd
 9:66 WINCHES

THE REEVING OF TACKLE BLOCKS

Tackle blocks give mechanical advant ge'
the more lines the blocks have the greater the
load that can be lifted with the same pulling
force. Note the reeving patterns on the sets of
tackle blocks in Figure 9-90.

SHACKLE
BLOCK

HOOK
BLOCK

1 PART 2 PARTS 3 PARTS 4 PARTS S PARTS

OF LINE OF LINE OF LINE OF LINE OF LINE

(9-90) Courtesy of Marlin and Black

Wire Ropes Ltd

It is good practice to use a shackle block as

the upper one of a pair and a hook block as
the lower one A shackle IS much stronger
.s.a;. a hook of the same size and the strain on
Ile upper block Is much greater than the
10%41 one. The lower block supports only the
goat- Ai/hems the upper block carries the load
as well as the hoisting strain. Also a hook is
more convenient on the lower block because
it can more readily be attached to or detached
from the load. Note that when reeving a set of
blocks where the rope leads from a block that
has more than two sheaves, attach the rope to
one of the center sheaves so that the hoisting
strain IS placed on the center of the block.
259
 WINCHES 9:67

SELECTING TACKLE BLOCKS EXAMPLE PROBLEM

A problem can arise in the shop or field in The load you want to lift is 72.480 lbs . and the
deciding what number of line Tackle Block to single line pull of the hoistdrum is 8000 lbs.
use When you know the weight of the load to The tackle sheaves you will use have bronze
be lifted and the line pull of the winch or hoist bushings.
drum that will do the pulling, the following
chart (Figure 9-91) will give you the number of Step 1: Find the ratio of load weight to line
line parts of the Tackle Block to use:
- 72480
load weight = = 9.06 ratio
lPlune pull 8000
Ratio for Ratio for
Number Bronze Anti-Friction
of Parts Bushed Bearing
Step
Step 2: Look up the ratio. or the one closest
of Line Sheaves Sheaves to it. either in the Bronze Bushed
Sheave column or the anti-friction
1 .96 .98
bearing sheave column. When you
2 1.87 1.94 find the ratio. look over on the same
3 2.75 2.88 line to the first column which gives
4 3.59 3.81 you the Number of Parts of line to
use. In this case the 9.06 is closest to
5 4.39 471
the 9.11. and so a tackle block with
6 5.16 5.60 12 line parts is needed.
7 5.90 6.47
8 6.60 7.32
9 7.27 8.16
10 7.91 8.98
11 8.52 9.79
12 9.11 10.6
13 9.68 11.4
14 10.2 12.1

15 10.7 12.9
16 11.2 13.6
17 11.7 14.3
18 12.2 15.0
19 12.6 157
20 13.0 16.4
21 13.4 17.0
22 13.8 173
23 14.2 18.3
24 14.5 18.9

(9-91)

Courtesy 01 Martin and stack

Wire Ropes 1 +/

260
 4
9:68 WINCHES

QUESTIONS WIRE ROPE 14 Wire rope inspections should be done:

1 Wire rope is made of three basic parts (a) daily.
What are they? (b) weekly.
2 When measuring the diameter of wire (c) monthly
rope. is the caliper placed on the crowns
(d) yearly.
of two opposite strands or in contact with
four opposite strands?
The frequency of lubrication of wire rope
3 As cable gets thicker. less of it can be depends on
wound on a drum. Using the table on
page 2 find the difference in feet be- (a) its size.
tween the amount of 5/8" cable that can (b) length.
be wound on a F-50 Hi-cap drum and the (c) severity of duty and corrosive con-
amount of 1" cable. ditions.
4 Give two functions that a fiber core will (d) weather conditions.
provide in a wire rope
16. What are cable clamps used for?
5 What are the advantages of steel core in
a wre rope) 17. True or False? A sheave groove that is
too large is better than one that is too
6 True or False') The rope with the small.
strongest steel Is the best for every job
Briefly support your answer 18 Briefly explain how the diameter of a
sheave affects wire rope life.
7 he figure 6 x 7 used to classify strands
in a wire rope means 19 When installing a new line on a tractor
winch drum.
(a) there are 42 wires per strand.
(a) hold onto the line and guide it onto
(b) there are 6 wires per strand and 7
the drum when operating the winch.
strands in the rope.
(b) use your foot to guide the line onto
(c) there are 6 strands in the rope and 7 the drum when operating the winch.
wires per strand.
(c) tail hold the line to a stump or tree
(d) there are 42 wires ir. the complete and wind the line onto the drum
rope iricludirg the core while pulling the tractor backwards.
8 When wire rope is preformed. it means (d) the line will spool automatically
that each wire arrl strand is preset to an when it is wound on.
exact shape
20 Correctly hstalled cable clamps should
9 List at least two advantages of preformed be arranged so that the:
wire rope
(a) clamp saddles are all on the live end
10 In one of its mech. js the term "lay of the line.
describes the direction of rotation of
wires in a rope What are the two basic (b) clamp saddles are all on the dead
lays and briefly describe the difference end ol the line.
between them Give an example where (c) clamp saddles are alternated be-
each is used tween the live c..d dead ends ol the
line.
11 The term lay- also rpplies to the direc-
tion of rotation 01 the strands in a rope (d) it doesn't matter.
Which is the most common. left lay or
right lay')
vi/h-t is the mrst common sign of wire
a deterioration?
rue or False? When inspecting a wire
4. ope. it should be supporting a load?

261
 WINCHES 9:69

21. When forming an eye on the end of a

1/2" piece of cable, the minimum number
of U-bolt clamps that can be used is:
(a) 2
(b) 3
(c) 4
(d) 5

22. When reeving tackle blocks. increasing

the number of line parts over sheaves:
(a) increases the mechanical ad-
vantage.
(b) decreases the mechanical ad-
vantage
(c) no change in mechanical ad-
vantage: just decreases the lifting
speed
(d) no change in mechanical ad-
vantage: lust increases the lifting
speed.

262
9:70 WINCHES

ANSWERS TRACTOR MOUNTED ANSWERS MAINTENANCE AND REPAIR

WINCHES OF TRACTOR MOUNTED WINCHES
1 Live P.T 0 from a torque converter. 1. True.
Live P.T.O. through a manual trans- 2 Condensation.
mission.
Hydraulic motor. 3. (b) Daily. weekly. monthly schedule.

2 (d) Overwind or underwind 4. 500 hours or 3 months

3 True. 5. False.

4 Overwind 6. True.

5 (d) (a). (b) and (c) are all correct. 7. Hydraulic ,est box.

6 Sliding gear
Power shift.
Hydraulic
7 (b) Tractor's master clutch must be
disengaged
8 By hydraulically applied clutch packs
9 Splash.
10 A hydraulic winch can be mounted in
most cases. in whatever location its
required. provided that hydraulic hoes
can be connected to power it.
11 (c) Band and multi-disc
12 (c) Spring applied and hydraulic
released
13 (a) Reel in
14 The housing acts as a cooler to cool the
hydraulic oil
15 Provides a guide for the cable. allowing
the cable to be reeled in at an angle
without being damaged.
16 A hydraulic pump and a hydraulic motor.

263
 WINCHES 9:71

ANSWERS HOIST WINCHES ANSWERS MAINTENANCE OF

HOIST WINCHES
1. The basic machine refers to the lower
and upper works. 1. Ensure that the working implement con-
The convertibility refers to various trolled by the drum she:* is in a safely
removable front ends which enable the lowered position and tension is off the
machine to do dilierent types of work. cable.

2. (e) Both (b) and (c) are right. 2. (d) Slips under load.

3 (b) Longer and runs looser. 3. (b) 1/32"

4. (1) Size. 4. False. They require regular, scheduled

lubrication.
(2) Ways of mounting.
(3) Activating mechanisms
5. Every 200 hours with multi-purpose
grease.
5 (a) A clutch
6 Brake
7. (a) Rear drum shaft.
8 The yarder drums have much larger
capacity.
9. (1) 3rooved.
(2) &tooth tapered.
10 (b) Increase
11 True
12. The multiple pieces are easier to remove
and install.
13 Air
14. (1) Hydraulic
(2) Air
15. They are stronger clutches and brakes
and can withstand heavier loads and
higher heal under increased machine
horsepower
16 Magnetic field.
17 False
18. The hydraulic winch.
(1) lakes less space.
(2) has simpler controls.
(3) requires fewer adjustments.

264
9:72 WINCHES

ANSWERS WIRE ROPE 16 To form a loop in a wire rope in order to

wire
attach the rope to a fixture.
strand 17 False
core 18 The less bend the wire rope is forced to
make the less strain will be imposed on
2 On the crowns of two opposite strands the rope. With less strain a rope will last
3 600 ft for the 518" cable and 215 ft. for longer
the 1" cable: so the difference is 600 19 (c) Tail hold the line to a stump or tree
215 -... 385 ft
and wind the line onto the drum while
4 A fiber core: pulling the tractor backwards.
(1) provides a cushion for the steel 20 (a) Clamp saddles are all on the live
strands end of the line
(2) Acts as an internal lubricator. 21 (b) 3.
5 A steel core: 22 (a) Increases the mechanical ad-
vantage.
11) Adds strength.
(2) Provides resistance to crushing.
(3) Gives heat protection
6 False. A rope with a ductile. flexible steel
may out-last a rope made of a steel with
a higher breaking strength
7. (c) There are 6 strands in the rope and
7 wires per strand.
8 Helical.
9. Preformed wire rope
(1) Won't unravel when cut.
(2) Is more flexible.
(3) Lasts longer.
(4) Is easier to splice.

10 Regular Lay wires in the strands la;

parallel to the rope.
Lang's lay wires in each strand lay in
the same direction as the strands of the
rope.
Regular lay general purpose rope.
Lang's lay applications where both
ends are fixed such as a hoist cable on a
shovel
11 Right lay.
12. Broken wires.
13 False
14. (b) Weekly.
15 (c) Severity of duty and corrosive con-
ditions.

265
 WINCHES 9:73

TASKS WINCHES, HOISTS (b) Attach the cable to the correct side
AND CABLES of the drum for either an over or an
under wind.
TRACTOR MOUNTED WINCHES
(c) Attach the other end of the cable to a
SCHEDULED MAINTENANCE secure tail hold and load the drum by
winching the crawler backwards.
1. Change the oil and filters and do minor
adjustments as outlined in the service 3. Make an eye on a piece of 1/2" (12 mm)
manual cable. using a thimble and wire rope cable
clamps of correct size. number and
SERVICE REPAIR placement to meet W.C.B. safety stan-
dards.
1 Remove and install a crawler winch
assembly using the correct tools. lifting
equipment. rigging equipment and safety
procedures outlined in the service
manual

CRANE AND SHOVEL HOIST WINCHES

SCHEDULED MAINTENANCE
1 Consulting the service manual. lubricate.
do minor clutch and;or brake adjustments.
inspect air lines or hydraulic lines and
make any minor repairs or replace any
damaged fines

SERVICE REPAIR
1 Remove and install a hoist winch from a
sho,lel or crane using the correct tools.
lifting equipment. rigging and safety prac-
tices outlined in the service manual. Rein-
stall the cable when complete.

CABLES, CLAMPS AND SHEAVES

SCHEDULED MAINTENANCE
1 Under the assistance of a journeyman.
make a cable inspection on both standing
and running cable such as would be found
on a shove! or crane. Write a report to in-
clude the measurements necessary to
check the cable and note any signs of
failure (See sec 54 18 W.C.B. Regulations
Paragraph 23 Wire Rope Rejection
criteria )

SERVICE REPAIR
1 Demonstrate correct care. handling and
storage of cable
2 Install a new drum cable on a crawler
mounted winch.
(a) Select the correct cable size and
length.

266