THE NECESSITY OF A

P L AT E A U E D
C Y L I N D E R WA L L F I N I S H

BRUSH RESEARCH MANUFACTURING CO., INC


 A “BRM-STATE-OF-THE-ART” ON CYLINDER-WALL FINISHING
A treatise beginning on page 4 of this booklet. A “Should-read”

DIRECTED TO
The Decision Makers of
National Standards Environmental Agencies, Energy Conservation Gps., Original Equipment Manufacturers of Reciprocating
Engines, Hydraulics, Pneumatics and Rebuilders of the above equipment.

STRESSING
The Importance of a Plateaued-Finish on any metal-rubbing-surface.

PLATEAUED-FINISH
Mass production methods in the past normally consisted of boring, then finishing to size using a rigid hone. The peaky finish
left by the rigid hone then had to be abraided down by piston rings which also had to have a peaky finish in what is known
as seating-in or breaking-in process. By the time the peaks had been worn down off the cylinder wall and also from the rings
we then had an engine or a hydraulic cylinder that was much less efficient than if the cylinder and rings had this
plateaued finish to begin with.

HOW MAY A PLATEAUED FINISH BE DEVELOPED BEFOREHAND?

This desirable plateau may be developed on a cylinder wall by the use of a resilient-based hone with a gentle pressure on the
walls that removes very little metal, but does remove the peaks from the surface instead of leaving it to be worn off by the
piston rings.

FLEX-HONE PROCESS
This is the name given to plateauing of the cylinder wall surface by the use of patented Flex-Hone. It is a resilient based
hone that is self centering, self aligning to the bore, and self compensating for wear. Available in different abrasive
grain sizes, it can produce almost any desired finish.

WHAT ARE THE ADVANTAGES?

Besides speeding up or in some cases eliminating the “breaking-in” process, the normal cut-torn and folded metal finish left
by the rigid hone is eliminated resulting in higher efficiencies. Two engine tests are included in this report which show the
types of advantages that might be expected – SAVINGS OF OIL, LOWERING OF BLOW-BY into the atmosphere,
eliminating some of the wear factor of piston rings and cylinder walls, and to some extent, eliminating the “green-engine”
that requires for example heavier-than-needed starters. And very important, the elimination of some of the major
causes leading to scuffing and probable engine failure.

WHAT ARE OTHER ADVANTAGES?

The same advantages of a plateaued finish are of equal importance in hydraulics and pneumatics to prolong the life of the
piston seals and give better sealing characteristics. Cross hole ports are also deburred and radiused. Longer life,
better performance and greater safety in operation.

ON THE NEXT PAGE – SEE THE ADVANTAGES IN SUMMARIZED FORM

Details on the following pages. See KC Report and VW test runs.

 © Copyright March, 2006 by Brush Research Manufacturing Co., Inc. Printed in USA
 AN EXPERIMENT TO EVALUATE THE EFFECTS OF A PLATEAUED FINISH
Using a standard VW engine as a test base for 4 controlled test runs using different types of cylinder wall finishes for results comparison. Tests were
conducted for Brush Research by and under the supervision of Larry Dawson, President of German Engine Exchange Inc., 15247 Nubia Street, Baldwin Park,
California, Larry Dawson Certifies the results as listed.

SUMMARIZED, THE TEST RESULTS ARE:

ENGINE TEST: (DETAILS FOLLOW FOR CLOSER STUDY)
BLOW-BY AT END OF TEST FINAL COMPRESSION READING
WATER PRESSEURE (4 CYLINDER AVERAGE)

“A” OEM FINISH 38” 150 PSI

“B” SUNNEN FINISH 31” ------18% LESS 155 PSI___3% HIGHER

“C” FLEX-HONED 12” ------68% LESS 161 PSI___7% HIGHER

“D” FLEX-HONED 15” ------60% LESS 161 PSI___7% HIGHER

OIL CONSUMPTION RING GAP INCREASE

ADDED DURING TEST (AVERAGE OF 8 RINGS)

“A” 24 FL. OZ. .0042”

“B” 20 FL. OZ. ------17% LESS .0043”___2% MORE

“C” 16 FL. OZ. ------33% LESS .0029”___31% LESS

“D” 8 FL. OZ. ------67% LESS .0016”___62% LESS

FUEL METAL TRACE ppm

DILUTION TIN IRON COPPER CHROMIUM ALUMINUM

“A” 2.8% 5 200 74 1 31

“B” 1.6% 5 180 67 1 30

“C” 1.3% <5 130 54 <1 27

“D” 1.2% 5 160 55 <1 35

NEW OIL 0% <5 <1 <1 <1 <1

CASE OF A DETROIT DIESEL ENGINE CONSUMING EXCESSIVE OIL WITH NEW IMPORTED LINERS
Imported replacement diesel liners, as received by and international US company, with a CLA finish ranging from 73 to 116 AA were stated to have con-
sumed 14 quarts of oil during a standardized test run. At the end of the test a “slobbering” effect was also observed.

It was reported that domestic made liners would normally consume 3 quarts of oil during similar tests.

Flex-Honing four of the imported liners reduced the finish to 39-42 CLA with plateaued areas. Test running with the opposing band of four liners, which were
standard domestic liners with a finish of 55-56 CLA, the oil consumption was reduced to 2 quarts. If all liners had been Flex-Honed the oil usage would
undoubtedly have been even lower.

Details and profiles of the test run on pages 15 thru 19.


 THE VERY CRITICAL ASPECT OF CYLINDER WALL FINISH:
PREAMBLE One of the major developments in the mass production of engines 15 or
Since the Flex-Hone was first conceived and introduced in 1968 our 20 years ago was the development of the diamond hone. This enabled
company has been almost totally involved with the problem of cylinder manufacturing to bore their blocks or liners within .001 to .002 of an inch
wall finishing and not only have we read and studied most articles and and then to use the diamond hone to remove the rest of the material to a
papers written on the subject but have worked with engine manufacturing controlled size. The diamond hone is too hard, it is too sharp, and the great
engineers throughout the world, not only on a direct basis but also through pressure required against the cylinder wall it leaves an extremely peaky
our exclusive distributors in all major countries of the world. A listing of the finish with cut, torn, and folded metal. Valuable graphite flakes are often
major engine manufacturers who have approved the Flex Hone process for either removed from the surface of the cylinder or is smeared over with
their service organizations appears on the inside cover of our Catalog and metal. The cross hatch grooves are inconsistent with some too deep or too
attests to the experimentation work that has been done. About three years fine, leaving a very undesirable surface-finish on which the rings must ride.
ago we produced a gold covered booklet on cylinder boring, honing and wall
finishing which was an observation on some of the common practices in this ENGINE FAILURE
field and in which we endeavored to explain the Flex-Hone and how it oper- Engine failure can be classified as any engine that suddenly starts to con-
ated. This gold book has since been translated into 15 languages and has sume large quantities of oil and has a large amount of blow-by. It usually
been widely circulated by many companies to all of their service dealers, and requires immediate attention or there is a possibility of piston seizure that
is used in many schools and technical colleges as a text and a reference on might even tear the liner apart. Many people drive nearly new automobiles
the subject. It is written in simple and easy to understand language and in that will consume up to 1 quart of oil every 500 miles and they may take
this booklet we wish to go one step further and try to present in brief form it in for a claim on warranty or may continue to drive it and condemn the
not only some of our opinions but highlights of what has already been writ- manufacturer for a bad engine.
ten on the subject by engineers in the United States and Western Europe. In
the early beginnings our campaigns on cylinder wall finishing were primarily MAJOR CAUSES OF ENGINE FAILURE
to introduce and sell the Flex-Hone. Now it has become a crusade to raise One of the leading factors in scuffing or what may be described in Europe as
engineering standards, to improve an engineered mechanism, to produce a scalds, burn-traces or burn marks. Scuffing is an English term that means
better product for the consumer and also in a small way to save energy and dragging your heels. When a piston ring drags on a cylinder wall surface
to reduce pollution. with an absence of oil film until the heat builds up to such a point that there
is a welding process that develops between the rings and the cylinder wall
A BRIEF HISTORY ON INTERNAL HONING then we will have a condition of metal transfer which is also called scuffing.
After World War II there was a tremendous demand for all sorts of consumer There are many underlying causes for scuffing and although we are going to
and durable goods and in particular engines—automobile, earth moving enumerate many of them, the one that we wish to consider at this point is
equipment and farm equipment. Excessive demand and competition for scuffing that may be caused by an unacceptable cylinder wall finish.
price, for less weight and more horse power demanded high performance
production method. FINISH
No surface is completely smooth and all surfaces have certain amounts of
Since Ramsbottom invented the piston ring in 1854 major developments roughness. Upon being magnified these surfaces will appear as peaks and
didn’t really begin until 1937 instituted by Castlemen. In 1957 and 1959 valleys along the axis on which they are measured. Also there are possibly
additional developments were made on the piston rings but it was not until repeating surface configurations which are known as lay. As on the ocean,
1969 through 1973 that investigations were begun to any great extent not only do we have a wind wave pattern but we also have the regularity
in cylinder wall finishing and the mating surfaces of the rings to the walls. if the ocean’s swells which is a conformation or a pattern that is repeated
Many large research projects have been going on since that time often or may be intermittently repeated. In the profiles that are shown later in
with greatly conflicting opinions depending upon the direction which each this report I would like you to be aware if the fact that the surface height
company took in their research. The controversy still continues and the as shown on the profile is magnified 2,000 times but that the length of
piston ring manufacturers not having any control over the honing processes the profile is magnified only 50 times. At the bottom of this paragraph we
attempt to design rings that will accommodate surface finishes produced by will show you the standard profile with the magnification and in the second
their major customers. One type of recommended wall finish is evolving and frame how this would appear if it was extended only 500 times the vertical
becoming accepted and that is the recommendation for a plateaued finish. instead of 2,000. In the third frame how it would appear at 200 times
However, some of the major manufacturers of liners, although they concede the vertical and in the fourth or bottom frame how it would appear at 50
that they should have a plateaued finish in their products, maintain that times the vertical and, therefore, equalized with the extension of 40 times
developing a plateaued finish is difficult and very expensive. the horizontal. While you are studying these comparisons we would also


like to indicate a simple method of arriving at the percentage of plateau. In One of our large major railroads who use the Flex-Hone® uses only a sur-
the top frame is a cast iron brake cylinder which was honed with a 180 grit face-analyzer which employs a skid and a meter. The shop superintendent
silicon carbide Flex-Hone which represents a plateaued area of approximately says that as long as their meter reads 35 AA, this was good enough for him.
65.3%. There are other more accurate and complicated ways of determin- He has no idea how that profile does appear and whether or not he has any
ing this plateau but the method that we have used is something that you plateaued surface. Also amazing is the lack of care in many large compa-
can determine yourself from your own profiles and obtain a relatively ac- nies in taking the profile of their engine liners or their cylinders. Their meters
curate figure. Plateau is the tabletop or the flat areas on which the rings are might be subjected to all the vibrations of the machine shop. We would like
required to ride or the bearing surface for the ring against the cylinder wall. to show you below how our particular machine was affected by auto traffic
In the second frame you will see that the profile that is shown there does when situated in the back of our shop with the machine mounted on a table
represent approximately .17 inches (4.232 mm) of actual surface. What saw with three rubber mats cushioning the table from the concrete floor. We
I find absolutely amazing is the lack of consciousness and concern of the also show the same machine situated on a desk in the office where a small
importance of proper surface profile on the part of some large companies. coin was dropped from a height of 3 inches onto the desk. The analyzer


 should be placed on a large slab of granite in a vibration proof area and the At the bottom of this paragraph you will see two surface finishes that, when
stylus reader completely separated from the chart recorder in order to avoid read on the direct re-out AA meter, will give you basically the same reading.
picking up resonance. But the profilometer will indicate that one is a very peaked unacceptable
finish and that the other is an acceptable plateaued finish. The plateaued
One large manufacturer of liners in the United States prefers to use only the finish will accept the piston rings on a wider more stable bearing surface and
fax-film in order to study the surface finish of their liners. From this they try will eliminate the necessity for the rings to wear off all of the peaks in its
to determine the depth of the finish and the amount of plateau. The fax- “bedding-in” process. There no longer is any need or any reason to provide
films should be used in conjunction with profiles and no firm opinions should or to allow this bedding-in process as a standard 2,000 miles running-in,
be held based upon methods that are peculiar to that company. which punishes the rings.

THE PLATEAUED FINISH

VARIANCES OF PRESSURE ON A BEARING SURFACE DUE TO
FINISH
Whether we are considering surface finish on the piston ring or the cylinder
wall or for that matter the main bearings of an engine, we do have two
pieces of metal in contact, working under pressure. As neither of these
two surfaces is completely smooth we must first realize that we will have a
contacting surfaces up to 5,000 pounds per square inch.
certain amount of interlocking.
This is based upon the knowledge that the pressure on the surface is the
We would first like to bring to your attention the differences in the bearing
load divided by the projected bearing area. This additional load caused by a
pressure on a different percentages of plateau on one square inch or one
peaky finish is going to have a lot to do with what happens when these two
square centimeter of two contacting surfaces. In the first illustration we do
metal surfaces start rubbing together.
have in theory two completely flat surfaces and on the top of number 1
let us assume that we have 500 pounds of pressure so that we have 500
A diesel engine in a small boat proceeding at 15 knots is going to have pis-
pounds per square inch pressure on the lower surface.
ton rings that exceed speeds of 30 miles per hour within their stroke. They
are going to stop and start an average of 4,000 times a minute, and during
If we have for example an 80% plateaued area then we will have a surface
an hour of running time are going to be dragged across the cylinder surface
pressure of 625 pounds per square inch. With a 40% plateau the 500
a distance of about 19 miles. A mental realization of this will emphasize
pounds pressure will now increase to 1.250 pounds per square inch.
the importance of the surface finish that is needed on a cylinder wall when
you think of the punishment that the piston ring is going to be subjected to
With a 10% plateaued area, such as we would find in an extremely peaked
in the first hour of running on a cylinder that may have a peaked finish.
surface, then the bearing area is 1/10 which increases the pressure of the
500 lbs. sq. in. 500 lbs. sq. in. 500 lbs. sq. in. 500 lbs. sq. in.

100% 80% 40% 10%

CONTACT Approx. plateau area Approx. plateau area Approx. plateau area
500 lbs. sq. in. 625 lbs. sq. in. 1250 lbs. sq. in. 5000 lbs. sq. in. pressure

THE EFFECT OF THIS BEARING AREA PRESSURE ON LUBRICATING air that has been sucked into the cylinder on its down-stroke and compresses
OIL it to a ratio of either 8 to 1 or 22 to 1 or any range in between. This pres-
The secret of course is lubricating oil and a condition that is going to permit sure gradually builds up not only on the top of the piston but also on the top
a film between the two metals so that there is no metal to metal contact. of the piston ring and the pressure gets down in behind the ring and forces it
In theory 1/10 of a micron of oil lubrication or film between two rubbing outward to the cylinder. On a diesel the compression of these gases builds
surfaces will prevent them from touching. One major oil company expert up heat until it reaches an ignition point and we have a resulting heat flame
has stated that all you need is oil one molecule thick. Oil on a standard ½” that in the combustion era is probably as hot, if not hotter than an oxyacety-
ball bearing one molecule think and enlarged to the size of the earth would lene torch. This instant heat, of course, expands the top of the cylinder head
only mean oil up to the depth of your waist. However, the viscosity of the and piston, and the top ring and also the top part of the liner. At this point
oil has been found to be very important and we now realize that we have we have some distortion prior to the downward movement of the piston. If
a lot of other factors that have to be considered. Some of these factors are the ring is not mated or seated to the cylinder wall the greatest blow-by is
the blow-by that removes the oil from between the top ring and the piston going to be at this initial point of contact or lack of contact. Any blow-by is
wall, the pressure of the ring against the wall which squeezes the oil from going to escape past the top ring, past the junction of the split in the ring
the surface and heat that destroys it. There must be a film of oil between (or at the horns) and the pressure is going to continue down to the second
these two rubbing surfaces if we are going to prevent metal to metal contact compression ring. The action there is going to be the same as with the first,
because the moment we do have this contact then we are going to have a where the pressure is going to get in behind the ring and force it out to the
condition which will lead to excessive heat and possible temporary welding surface. There is a second danger at this point that we might suffer ring-col-
of one surface to another. lapse of the first ring and oil carbonization might build up between the ring
and its groove which will prevent its future function and ring breakage will
There is solid friction and fluid friction and there are three major features result. Sometimes there is so much blow-by on the first ring, that the major
to determine the amount of each. Solid friction is the load or the amount part of the pressure is on the second ring as we quite often see scuffing
of pressure that is placed upon the metal whether it be a ring or a bearing. starting to develop at the second ring before we see scuffing on the first
Three factors in order of importance are first, the contact area which supports one. If these hot blow-by gases escape between the ring and the cylinder
the load; second, the speed at which it travels; and third, the viscosity of wall, then at this point any oil film that might be there is going to be burned
the oil itself. Contact area, speed and lubrication. Consider the fact that oil off. When we talk about the use of the Flex-Hone we always say to be sure
is going to be squeezed out either by the pressure of the ring against the bring the Flex-Hone out of the cylinder while it is still rotating, because we
cylinder wall or the pressure of the connecting rod against the bearing. In want to produce a uniform cross-hatch finish completely throughout the en-
order to have full film lubrication the oil must be replaced faster than what tire length of the cylinder and particularly at the top of the ring travel. This
it is squeezed out. If the speed is too great or the area is too small for advice then becomes more apparent to you because of the utmost necessity
the load, then solid friction with accelerated wear is going to be the result. of trying to have a plateaued finish at the top of the ring travel to eliminate
When an engine is started up from a standing stop we are going to pass as much as possible the initial blow-by with the destroying of whatever oil
through three phases of lubrication. This period of time is going to last from film might be there. The pressure of the ring to the cylinder wall is going
the time you start the engine until you see the oil pressure gauge reach its to have a squeeze action on whatever lubrication might have been placed
proper operating pressure. We will probably start off by having almost metal there by the upward travel of the piston before its power stroke and by the
to metal contact with very little or no lubrication. Then we will have a thin connecting rod splashing or otherwise depositing oil on the cylinder wall
film – a boundary or border-like lubrication. Then a thick film or a full film itself. On its downward stroke the oil rings are going to scrape the oil back
lubrication. It is very important, therefore, to have a surface that is capable into the oil reservoir in the pan. The cylinder wall is cooled by the oil as the
of being wetted out of a surface that is going to maintain and hold a thin oil becomes a heat-sink. It is also going to be cooled in a wet sleeve by the
film of oil either when the engine is in operation or after it has stopped and water circulating around portions of the liner. The block itself is also going to
is standing still. With a porous surface as you might find in some chrome be cooled by the oil going down through the oil galleries. The piston and the
cylinders or in some chrome rings, the oil will drain from the porosity ring which are much hotter than the cylinder wall, are going to be cooled by
whereas if you have a proper cross hatch finish with the proper valleys for the cylinder wall itself on its downward stroke and by the taking in of new
oil retention the oil may remain wetted out on that surface. Viscosities of air. We see that we have rapid expansion and contraction of the piston and
oils are an extremely important consideration at this point depending upon the rings and actually the liner itself. One of the major causes of scuffing,
compression ratios, clearances, types of rings and cylinder wall surfaces, particularly in the early running-in stages, is his initial lack of seating on a
engine types, lubrications, heat of the engines, etc. peaked finish which might be alleviated greatly by having a plateaued finish.
All of this is extremely important on a new engine where a plateau might
help eliminate or alleviate the start of the troubles. A peaky finish will give
BLOW-BY
us less contact area for the rings themselves, thus greatly increasing the load
A piston on its upstroke really acts like an air compressor. It takes all of the
or the pressure. Because of the lessening of this contact area we have the


 possibility of great blow-by thus destroying the oil film with greatly increased PISTON RING TYPES
temperatures. This results in the rings themselves heating to a point Rings of all types have been experimented with and tested in order to give
whereby thy might melt the peaked metal off the cylinder wall and weld the optimum contact area to the cylinder wall, to prevent the rings from
it to the ring. At this point we have scuffing. Be sure to study the engine sticking, and allowing them to operate freely within the ring grooves and to
tests on the effects of finish. have the proper outward pressure caused by the expanding gasses in the
power stroke. Many different shapes and surface finishes and surface treat-
The rings themselves often have to do the final honing job and remove by ments have been developed mainly in order to accommodate a particular
abrasion all the peaks from the surface of the cylinder wall. In doing this engine manufacturer to overcome blow-by, excessive heat, elimination of oil
the metal is worn away, imbedding away, imbedding particles of this metal film, smearing of the metal and the resulting scuffing. One car manufacturer
into the cylinder wall and sometimes into the ring. If you have chrome is now working with a piston ring manufacturer to develop a ring design
rings, the chrome laminate is sometimes removed from the ring face itself. that would reduce the outward ring pressure to 50% or less in order to
The heat reaches such a temperature that instead of the metal being worn reduce the problems that we have been discussing. Along with ring design
down in a normal abraded fashion by the rings, it is smeared in a plastic different component expansions must be taken into consideration. As for an
formation against the cylinder wall. This is evident in some of the cylinder example when using aluminum pistons in a cast iron block, it is important to
wall surfaces that you see after a failure during a running-in process. This determine the proper cold clearance between pistons and bore. Perhaps, as
plastic deformation or smearing of the metal down a cylinder wall removes an ex- ample, the cold clearance should be .005 inches in order to insure a
all of the necessary cross hatch that is needed to hold a film of oil. The rigid reliable hot clearance of .0007 for minimum blow-by. Rings in their upwards
hone often covers up in its smearing and plowing action the very important and downwards travel tend to become worn off and have a barrel-shaped
graphite particles that are part of the cylinder wall surface. These graphite surface so a popular ring today is one that is made in that configuration
particles besides being a lubricant themselves will also hold large amounts of in an attempt to prevent this initial wear on the ring, and its subsequent
lubrication and the Flex- Hone will cut the surface finish clear and expose the damage to the cylinder walls. Rings are chromed, they are treated with
graphite particles. We used to say during our very early advertising, ‘’will molybdenum, the cylinder walls themselves are chemically treated by Nitrid-
allow the walls to breathe.” This breathing or opening up of the surface per- ing and other hardness treatments and cylinder walls are chromed. So far
mits oil retention and lubrication. Otherwise this plastic deformation of the all of these are still in the great stage of experimentation and development
cylinder wall metal and the changing of the micro sub-structure to an inferior and many new innovations will continue to be introduced as the years go by.
status is compounded and additional scuffing is an inevitable result. In the midst of all this activity and research work that is going on with ring
development and cylinder wall preparation, I believe that the Flex-Hone has
OTHER CONTRIBUTING FACTORS TO SCUFFING arrived at just the right time. As a plateau developing tool, the Flex-Hone is
In the early days of selling to the small engine rebuilder we used to get the something that there is an immediate great need of.
comment that the Flex-Hone was great for the ‘’Hard Spots’’ or the ‘’Hot
Spots’’ What did they mean? On an originally finished cylinder wall there ADDITIONAL PROBLEMS CAUSED BY SCUFFING
might be a spot where dirt or imbedded metal (such as the torn and folded There is general agreement that scuffing is a running-in problem. The dam-
metal from heavy rigid honing) which would cause a greater spot resistance aged surfaces have quite often been associated with the appearance of a
to the rings. This area would have greater heat build-up from the increased white layer. This white layer is noticeable in both steels and cast irons and
friction and the metal would expand at this point forming a ‘’bump.’’ this white layer usually forms not only during the running-in but generally
Sometimes these bumps got abraded off and sometimes they just continued increases in coverage over the surface prior to the formation of an oxide
to get bigger, thus being just another cause of scuffing. Excessive heating which seems to take place towards the end of the running-in process. This
caused this Hard Spot which originally was a Hot Spot, which was originally white layer has been studied and although the researchers do not know
debris imbedded into the wall or a fault in the finish. Some of these spots exactly how it forms, it seems to be a Carbide structure. Almost always this
may be eliminated by proper original honing methods as they are difficult to white layer didn’t form immediately, but was proceeded by a plastic flow of
analyze after they have developed. the surface, which deforms the subsurface structure, and causes hardening
and other transformations of the metal structure itself. This hardened surface
When a surface is not too rough and there is a large contact area which will layer usually oxidizes, and after wear would eventually disappear off the
hold the necessary film of oil there is always some wear that takes place surface. This white layer also appeared on piston rings, and the heat affected
between the rings and the cylinder wall. In developing a mating surface, microstructure would extend in depth up to about 10 microns with about
there is a mild abrasion which at some point may cause heat build-up to a 10 microns on the cylinder wall. The white layer, as we stated, seemed to
point where there may be some initial minor scuffing. If the rings bed down be a carbide in a very small crystal size which seemed to be a product of
or seat during this initial period, then this initial scuffing may not be too seri- the deformation of the metal together with high friction temperatures. It is
ous, and may completely disappear, and providing no great damage is done, usually produced under unlubricated conditions with very high temperatures.
the scuffing may even heal itself. It is very hard and brittle and eventually will fall from the surface to form an


abrasive-wear debris, and to be the result of and not the cause of scuffing. Let’s go back to diamond honing which we agreed is an excellent means of
Graphite which is present in cast iron in different forms reduces the cuff bringing a bore to its proper size, but it is an operation that must be very
science of friction and actually to quite an even, resists scuffing in and after carefully controlled. It must be a suitable honing procedure, stones must be
the oxide film is formed these graphite particles also form areas which will straight and dressed or it’s going to produce totally unsuitable surfaces. Fol-
retain and hold oil. low this, however, with a secondary honing method that is going to remove
the peaks and establish a plateaued finish, the Flex-Hone may correct a lot
SOLUTION of the problems that we have just discussed and which contribute to piston
There are many, many reasons for engine failure, break- down, scuffing, or ring scuffing and engine failure. Many piston rings have been made with
for the local breakdown of oil film, and almost any engineer can give you up hardened rough surfaces in order to do the final honing, and perhaps if a
to 50 reasons that may be Contributing factors. This is mentioned because plateaued finish yare developed these very hard and abrasive surfaces might
we don’t want you to get the idea that we feel that everything is going not be necessary, as they might also contribute to the harm. We will show
to depend upon cylinder wall finish because it does not. One of the prime at the bottom of this paragraph a profile of a molybdenum ring in its new
causes, of course, is poor surface finish of the bore. Then we have many state. We have included in this booklet the Korody-Colyer test report and
other causes such as the wrong design of rings, over- heating, distortion our own four stage engine test-runs. The profile of the ring that was used
of the rings, the pistons, the top of the cylinder; incorrect use of oil, or the after 10 hours of running, (below) shows what happens to a ring when it
wrong viscosity of the oil; improper fuel mixtures, carbonizing or sticking of is subjected to this severe running-in process of bedding down on a peaked
the rings themselves; ring collapse or breakage; improper cooling or water surface. So it is altogether possible that a different type of ring may be more
distribution In the cylinder block; incorrect oil galleries which also should aid suitable on a Flex-Hone plateaued finish than the ring best suited for the
in the cooling; improper oiling from the connecting rod itself into the cylinder ‘’unacceptable finish’’ which is all too common today. Standard cast iron
wall: incorrect fuel, valve clearances, fuel mixtures. Any or all of these may rings have been found to be excellent with a scuff resistance somewhere
be at fault. The one thing that the Flex-Hone can do and that is possibly to between the chromium and the molybdenum and it might be interesting for
assist in one of these areas, which is to improve a poor surface finish that you to measure the before-and-after ring gap difference between operations
might be the major initial contributing fault. over an equivalent number of mites when running on an unacceptable finish
versus an acceptable plateaued finish.

PROFILES ABOVE: On the left is the surface of a new Moly coated ring. On the right is the profile of a new AM top ring after 10 hours of running-in on a very peaky rigid hone finish as
reported in the K-C Report (pg 15). Build-up in the center is probably carbon deposit. Wear-factor did plateau the ring as it originally had a thread patterned surface.

NEW BORING IMPROVEMENTS

Kwik-Way of 500 57th St., Marion, Iowa USA for several years have endorsed the Flex-Hone as a finishing tool to their boring bar without the necessity
of using a rigid hone to bring the bore to a required size. The KW boring bar can bore to .0005’’ or less with a low CLA surface enabling the use of the
Flex-Hone to produce the desired plateaued finish. In Germany the KW boring bar and the FH are presented as a team. Van Norman Machine Co. of 3640
Main St., of Springfield Mass. have recently conducted some experiments with us and intend presenting to the owners of Van Norman Machines, tools and
recommendations to also bore to size and Flex-Hone finish. We feel sure that soon all manufacturers of boring equipment will follow suit.

SUMMARY perature by reducing the load on the piston ring and those sections of the
What we believe the engine manufacturers really want is to have the bore at the point of contact. Greater area contact between the ring and the
lowest possible temperature between the interface of the ring and the bore, plateaued finish is going to lower the blow-by. Valley type finish is going to
lowered blow-by and a defect-free bore surface which is going to retain a help retain the lubricant which is needed for rapid ring seating and resistance
lubricant. Lowering the ring-bore interface temperature is going to be helped or elimination of scuffing. A cross hatch finish is also going to help spread
by reducing the amount of friction, or the metal that the ring has to remove the oil sideways on the up and down strike of the piston instead if forcing it
in its bedding-in process, and by a plateaued finish to also help to eliminate up into the combustion chamber. Scuffing is gross surface damage caused
that wear and to give a larger bearing surface which In itself will reduce tem- by local welds between the sliding surfaces, and we feel that our Flex-Hone
plateaued finish is going to help prevent this initial form of seizure.

 AN EXPERIMENT TO EVALUATE THE EFFECTS OF A PLATEAUED FINISH
Using a standard VW engine as a test base for 4 controlled test runs using “D” engine was run with a Kolbschmidt cylinder set except that the
different types of cylinder wall finishes for results comparison. Tests were cylinders had been Flex-Honed for 30 seconds with a GBD 3-
conducted for Brush Research by and under the supervision of Larry Dawson, 1/2’/ 180 grit SC FLEX-HONE. Stock O.E.M. piston rings and
President of German Engine Exchange Inc., pistons were run as received from the factory. New bearing and
15247 Nubia Street, Baldwin Park, California. Larry Dawson Certifies the valves were replaced and valve seats resurfaced as were all above
results as listed. engines.
The VW engine was the same for all test runs changing only matched sets
of cylinders, pistons, piston rings, piston pins, new bearings, intake and Cylinder wall finish profiles were taken before and after each test using a
exhaust valves and engine oil. The same crankcase, crankshaft, connecting Gould Surfanalyzer. The Surfanalyzer uses a .0001/’ radius diamond tip
rods, cylinder heads, camshaft and running accessories (carburetor, mani- stylus with a system accuracy of +- 1 % full scale readings and records flat-
folds, cooling fan, etc.) were rerun in each test run to duplicate test base for ness of +-1 micro-inch per 14 inch of travel. The tests were run on a Stuska
a fair comparison of the various cylinder wall finishes. Dynometer for a 24 hour period under a scheduled sequence of various RPM
“A” engine was assembled using new O.E.M. Kolbenschmidt cylinder and BHP load conditions. Measurements were taken for comparison at the
assembly set exactly as received from the factory in Germany. end of 7 time intervals during each test run. The measurements consisted of
‘’B’’ engine was assembled using another matched set of Kolbschmidt blow-by, compression, oil addition, oil pressure and cylinder head tempera-
assemblies except that the cylinder wall surface had been ture.
refinished with a Sunnen hone Model LBB-171O using
AN-200 (150 grit size) honing stones. Stock O.E.M. The basic test engine had a sealed crankcase system from which the pres-
rings were assembled after honing. New bearings and valves were sure build up from blow-by was measured using a water manometer. The 7
replaced and the valve seats resurfaced. readings were averaged for each test run to give an overall comparison of
“C” engine assembled similar to above engines except that 2 cylinders each run plus the final blow-by measurement gives a ring seating compari-
were Flex-Honed with 120 grit SC and 2 cylinders with 180 grit son at the end of 24 hours of running in.
SC. Bearings were also Flex-Honed to develop a cross-hatched
plateaued finish. Piston rings were modified on some
of the cylinders. No. 1 cylinder used a previously-run ring set that
had been plateaued through 24 hours of running wear. No. 2 cyl-
inder was run with a Hastings piston ring set which had
been slightly lapped on the leading edges. No. 3 cylinder had a
standard O.E.M. ring set. No. 4 cylinder used an O.E.M. ring set
that had been lapped by Brush Research to remove the peaks and
plateau the ring surface.

BLOW-BY: measured in inches-of-water pressure build-up in crankcase.

ENGINE TEST AVERAGE OF 7 READINGS TAKEN DURING TEST RUN READINGS AT END OF TEST RUN
“A” OEM FINISH 35” H20 38” H2O
“B” SUNNEN FINISH 39” ------11% more 31” ------18% more
“C” FLEX-HONED 28” ------20% less 12” ------68% more
“D” FLEX-HONED 23” ------34% less 15” ------60% more

COMPRESSION
After the completion of the four 24 hour test runs all cylinder sets were again reassembled on the test engine and run for a 3 minute warm up period. Using
a full charged battery, a new starter and the same cylinder heads without rework, the compression was taken immediately after shut down and after 10
minutes cooling. By creating identical conditions, a fair judgment of compression figures can be used.
AVERAGE OF 4 CYLINDERS
“A” OEM FINISH 150 P.S.I.
“B” SUNNEN FINISH 155 P.S.I. -------------3% higher
“C” FLEX-HONED 161 P.S.I. --------------7% higher
“D” FLEX-HONED 161 P.S.I. --------------7% hgiher
10
OIL CONSUMPTION
There are many variables for oil consumption and cylinder wall finish is one of the main items to consider. The results of this particular test are not conclusive
but give an indication of the effect cylinder wall finish can have under the same set of conditions.
Oil consumption for these tests was calculated by using the amount of oil needed to maintain the oil level at the full mark throughout each test. After each
test the engine oil was collected and sent to an oil analysis laboratory for complete physical, chemical and spectrographic tests.

“A” OEM FINISH 24 fluid ounces (710 CC)

“B” SUNNEN FINISH 20 fluid ounces (591 CC) ------------17%
“C” FLEX-HONE FINISH 16 fluid ounces (473CC) ------------ 33%
“D” FLEX-HONE FINISH 8 fluid ounces (237 CC) ------------ 67%

CYLINDER HEAD TEMPERATURE

RING GAP INCREASE Cylinder head temp. was measured at spark plug no.1 position
Average of all compression rings in each test Temperature is the average of 7 readings taken during a 24 hr test
“A” OEM FINISH .0042” 257˚ F ( 125˚ C )
“B” SUNNEN FINISH .0043”___2% MORE 249˚ F ( 121˚ C )
“C” FLEX-HONE FINISH .0029”___31% LESS 232˚ F ( 111˚ C )
“D” FLEX-HONE FINISH .0016”___62% LESS 244˚ F ( 118˚ C )

ENGINE OIL ANALYSIS TEST RESULTS

METAL TRACE ppm
FUEL
DILUTION IRON COPPER CHROMIUM TIN ALUMINUM
“A” 2.8% 200 74 1 5 31
“B” 1.6% 180 67 1 5 30
“C” 1.3% 130 54 1 <5 27
“D” 1.2% 160 55 1 5 35
NEW OIL 0% 1 <1 <1 <5 <1
While one particular test by itself does not give an absolute answer it does reinforce by giving a strong indication of some typical results to expect when us-
ing the Flex-Hone in any particular application. The unique finish produced by the Flex-Hone is uniform and consistent from cylinder to cylinder. The plateaued
finish which the Flex-Hone process produces on any cylinder can be varied to fit any particular requirement from combustion engine cylinders to pneumatic or
hydraulic cylinders with excellent results. The Flex-Hone process gives quicker ring seating with better oil control and reduction in blow-by from superior ring
sealing. Pneumatic and hydraulic applications report better sealing characteristics and longer seal life using appropriate Flex-Hones for cylinder wall finishing.
Elimination of problems of seal wear and shearing across cylinder cross holes and ports have been reported by users of the Flex- Hone.

Condensed profiles of cylinder wall finishes for comparison of cylinder wear. Profiles were all taken from the same areas of the #2 cylinder on each test
engine. Area of ring travel is the right hand portion of above profiles. Magnification is 2000 times vertical (.00005’/ or .00127mm division) and 10 times
horizontal (.010’/ or .254 mm per division).
11
 Engine “A’’ Cylinder #2 showing typical profiles of # O.E.M. finish before Engine ‘’B’’ Cylinder #2 profiles of Sunnen honed finish before and after test
and after test run. run.

Flex-Honed engines ‘’C’’ and ‘’D’’ cylinders from # 2 position, profiles of O.E.M. finish as received, profiles of surface finish after using Flex-Hone GBD away
180 grit for 30 seconds and profiles of Flex-Hone surface finish after 24 hours of running in test engines. Compare ‘’run-in’’ surface finish in ring travel area
of ‘’A’’ to Flex-Hone finish on C and D final profiles.

12
Flex-Honed VW engine ‘’C’’ profiles of all
cylinders after 24 hours of running. Profiles
were taken at end of piston ring travel area.
Cylinders C-1 and C-2 were 180 grit Flex-
Honed before test run. Cylinder C-3 and C-4
were 120 grit Flex-Honed. Specially prepared
ring sets were used in test run.

See ‘’after’’ photos of No. 2 cylinder next

page.

Flex-Honed VW engine ‘’D’’ profiles of cylin-

ders after 24 hours of running. All cylinders
were 180 grit Flex-Honed for 30 seconds
before test run.

13
 O.E.M. finish after 24 hours of running in engine “A.” Cylinder wall
had a glazed appearance and many fine vertical scratches.

Sunnen finish after 24 hours of running in engine “B.” Finish was

similar to above with a glazed appearance in ring travel area and
many fine vertical scratches.

FLEX-HONE finish after 24 hours of running in engine “C.” Cylinder

wall still shows the unique appearance of Flex-Hone finish with
cross-hatch clearly visible in entire ring travel area. Surface has a
slight matt appearance and “open” look, without any sign of glaze
or burnishing.

14
 DETAILS ON THE CORRECTIONS OF A DIESEL OIL
CONSUMPTION PROBLEM--
KORODY-COLYER REPORT
On March 3, 1977 Korody-Colyer Corporation in Wilmington, California phoned Brush Research regarding a problem of excessive engine oil consumption with
their replacement cylinder liners for series 71 Detroit Diesel engines. They were using a new imported source for their cylinder liners, a company call Nippon
Piston Ring Co.,Ltd.

The new cylinders as received from NPR reported to consume 14 quarts of engine oil when run in a test engine for 10 hours and had excessive ‘’Slobbering’’
at the end of the test run. Typical oil consumption stated for cylinders from General Motors or Sealed Power would be approximately 3 quarts of oil in the
same 10 hour test. After analyzing the cylinders as received from NPR we found the profile to be very peaky and not consistent from cylinder to cylinder
with the C.L.A. finish ranging from 73 to 116 p’’ AA (1.85 to 2.95 um). We decided to use a GBD 4-14’/ FLEX-HONE 120 grit silicon carbide in the NPR
cylinders for 2 minutes using Flex-Hone Oil as a lubricant.

The 4 NPR Flex-Honed cylinders were assembled on one side of a 8V-71 Detroit Diesel engine in Kor|y-Colyer’s test lab. The Flex-Honed finish was very
consistent with a C.L.A. of 30 to 42 p’’ AA (.99 to 1.07 um). The other side of the V-8 engine had 4 Sealed Power already in- stalled, C.L.A. finish of 55 to
56 p’’ AA (1.40 to 1.42um), waiting for the Flex-Honed cylinders as results were urgently required.

The engine was run for a specified 10 hour sequence of RPM and horsepower loading on the test dynometer at Korody-Colyer. After the 10 hour test period
the engine was run for 30 minutes at a very light load as a final test of ring seating and oil control. Engines in which the rings have not seated allow so
much oil past the rings and out the exhaust ports that the oil will leak out of the exhaust manifold gasket and run down the side of the engine, this effect is
what the engineless at Korody-Colyer describe as ‘’Slobbering’’. If the final test was not run at light load the ‘’Slobbering’’ effect would not be found as the
excessive oil would be burned up by the high exhaust temperatures at maximum horsepower loads.

The engine in which the Flex-Honed cylinder liners were run consumed only 2 quarts of oil during the 10 hours of the test run. As typical oil consumption
stated for this engine with all S.P. or GMC liners would be 3 quads of oil, then it could be assumed that 4 sap- or GMC cylinders would use 114 quarts of oil.
The conclusion is that an engine with all 8 cylinders Flex-Honed to a Plateaued Finish would then probably consume only 1 quart.

We visited the site during the test period and the engine was stopped after the first 1 ½ hours of the test had been completed. The exhaust manifolds were
removed and the ports examined. A wet look inside the pods is an indication of excessive oil being used and indicates which bores are responsible. Three
of the Sealed Power cylinders showed a faint sheen inside the exhaust arts indicating only slight oil passage. Only one of the Flex- Honed cylinders showed
a faint sheen inside the pod. At the completion of the 10 hour test the exhaust ports were examined on both sides of the engine and none of the ports
showed any signs of oil passage.

We also received additional cylinders from Korody-Colyer for examination and Flex-Hone experimentation. The results are attached with comments. The
Detroit Diesel Engine is a two-cycle engine which has different requirements for ring seating and oil control than a four-cycle engine. The DD engine has two
sets of rings, one set near the top of the piston are for combustion citron and act as an intake valve as they go past the intake ports on the cylinder wall. The
bottom set of rings are mainly for oil control and do not pass the ports and are not subject to combustion pressures. Seating-in of the bottom set of rings is
very similar to the problems involved in ring seating of an air compressor.

As is clearly visible on the Sealed Power cylinders, the profile created by the Flex-Hone is virtually identical to the finish produced by running the same type
of cylinder in an engine under load for 10 hours. The Flex-Hone accomplished in 2 minutes the same finish that 10 hours of running produce in a new Sealed
Power cylinder.

All surface profiles were taken on a Gould Surfanalyzer 15 system using a .0001”radius diamond tip stylus, stylus force of 800 mg. System accuracy ±1 %
full scale. Sensitivity of 50 microinches per chart division was used on following profiles, system has the capability of sensitivity of 5 microinches per chart
division. Flatness from a horizontal plane is ±1 microinch for 1/2 inch of travel. Profile magnification is 2000 times on the vertical axis and 50 times on
the horizontal axis.

15
 NIPPON #1 CYLINDER:
A new cylinder as received from manufacturer. This was one of six new Nippon liners that were brought to Brush Research by Korody-Colyer because of ring
seating problems. This cylinder shows the typical peaky profile of these cylinders as received. This cylinder had an AA finish of 73 µ” (1.85 um). After using
a Flex- Hone GBD 4 ½” 120 grit Silicon Carbide for two minutes in the above bore the finish was improved to a semi- plateaued AA finish of 39 µ” (1 um).
Material removed after two minutes of honing .00025’’ (.006 mm). The cylinder material had a high boron content and difficult to hone as compared to a
cast iron engine block.

NIPPON #2 CYLINDER:
A new cylinder as received showing the very peaky finish typical of the new Nippon cylinders. This bore had an AA finish of 116 µ (2.95 um). After using a
180 grit Silicon Carbide Flex-Hone for two minutes the finish was improved to a plateaued AA of 41 µ” (1.04 um). After an additional two minutes of Flex-
Honing the surface finish was not changed much at an M of 42 µ’’ due to the original rough surface and the hardness of the material being honed.

NIPPON #3 CYLINDER:
As received after being run for 10 hours in a V-8 test engine at Korody-Colyer. During the test the engine was reported to have consumed 14 quarts of
lubrication oil (typical usage for General Motors or Sealed Power cylinders was stated to be 3 quarts). The area above the ports is subject to combustion pres-
sure and showed considerable ring blow-by as discoloration on the wall surface. The profile of the surface shows very little plateau from the rings and the AA
of 75 µ” (1.90 um) is still very peaky. The area below the ported area was typical of the finish above the pods with an AA finish of 70 µ, (1.78 um).

16
NIPPON #4 CYLINDER:
As received after being run for 10 hours. Profile of cylinder above ports shows no signs of plateau from ring seating. As received AA was 68 µ’’ (1.73 um).
The profile of the cylinder area below the ports shows minimal signs of ring seating and an AA of 46 µ” (1.17 um).

NIPPON #5 CYLINDER:
This cylinder was Flex-Honed for two minutes with the GBD 4 ½” Flex-Hone 120 grit Silicon Carbide using Flex-Hone oil for a lubricant before the 10 hour
run-in test at Korody-Colyer. The profiles were taken of the cylinder bore above and below the ported area. Piston ring seating was excellent as the engine
consumed only 2 quarts of lubrication oil during the 10 hour test. The plateau profile is evident in both ring travel areas. Deep scratches from the original
manufacturing are still evident as valleys much deeper than the regular profile pattern.

NIPPON #6 CYLINDER:
This cylinder is one of the four cylinders run in for 10 hours at Korody-Colyer in their engine test. The excellent plateau profile finish is quite evident in both
areas of the cylinder. This cylinder had been Flex-Honed for two minutes with 120 grit Silicon Carbide using Flex-Hone oil as a lubricant. The original Flex-
Hone finish is still visible on the left hand portion of the profile beyond the ring travel area. Approximately 75 millionths of an inch (.000075” or .001905
mm) of stock was removed by the piston during the 10 hours of run in.

17
 NIPPON #7 & #8 CYLINDERS:
Profiles of the cylinder areas above and below the intake ports shows the excellent plateau created after running for 10 hours on a Flex-Honed surface.
The cylinders were Flex-Honed for two minutes before run in a test engine. The original Flex-Hone finish is visible on the left hand portion of the profile of
cylinder #8. Approximately 75 millionths of an inch (.001905 mm) of stock was removed during ring seating. During the 10 hour test the engine consumed
2 quarts of lubrication oil (typical usage during a 10 hour test is about 3 quarts when using either General Motors or Sealed Power cylinders in the same
engine.)

18
SEALED POWER #1:
A new cylinder as received from Sealed Power with a consistent and uniform AA finish of 55 µ” (1.4 um) throughout the bore. After Flex-Honing for two
minutes with 180 grit Silicon Carbide the surface was improved to a 23 µ’’ (.59 um) plateau profile typical of the Flex-Hone. Stock removal after two
minutes .0001-(.00254 mm).

SEALED POWER #2:

A Sealed Poker cylinder received after having been run for 10 hours in a test engine. The finish is an excellent plateau profile in the areas above and below
the intake ports. The AA 24 µ’’ (.62 um) finish above the ports is virtually identical to the Flex-Hone finish created in the new Sealed Power cylinder #1
above. The Flex-Hone accomplished in two minutes the same profile finish that was produced by 10 hours of running in an engine under load. The area
below the ports had an AA of 28 µ’’ (.72 um) with a similar plateau profile finish.

GM #1 CYLINDER:
Profile of a new cylinder as received from General Motors showing a finish of AA 56 µ” (1.42um). Finish is consistent and uniform through out bore. After
Flex-Honing for one minute with 180 grit Silicon Carbide the finish was improved to an AA of 35 µ’’ (.89 um) with an improvement in plateau profile.

19
 BEARING If the concept of a plateaued finish is desirable for a cylinder wall,
Mains, Con Rod, Cam
THEN SHOULD IT NOT APPLY T0:
It is generally assumed that the major damage to bearings is caused during
PISTON RING SURFACES,
the first 10, 15, or 20 seconds after an engine is started from a cold start
BEARING SURFACES,
before thin - film or full - film lubrication is reached. In our Treatise we
VALVE GUIDES,
pointed out the effects of ‘’bearing’’ or load pressure not only involved in the
AND ANY TWO METAL RUBBING SURFACES?
squeeze action on oil but also the heat causing factor. We also brought to
your attention that oil drains from a ‘’smooth surface” or from a surface that
Usually the main concern is COST. Most engineers tell us that Quality Control
has only porosity. If a valley area is necessary in a cylinder wall to retain or
is not their concern, but if they can get the same or equivalent finish,
hold oil, and if a cross hatch is necessary to spread the oil, and if you agree
performance, etc. as is NOW accepted or is common practice within their
with this concept, then should not the same surface be on the face of a
company or field, AT A COST SAVINGS then that is all they are interested in.
bearing for the same reasons?
COST SAVINGS ONLY. They are not in a position to change anything so they
express no opinions. If they can save a penny on the operation, or reduce
Any time we have suggested trying a Flex-Hone type finish on a bearing
its weight, they are heros. We need more than Government Regulation and
face, we got expressions of horror, and amazement that we should even
Competition to force change, we need the constant desire to improve for the
suggest such a thing. So we tried it out on Engine Jest ‘’C ‘ One large
benefit of the consumer, which In short time will be of mutual benefit for all.
US Bearing Manufacturer agreed with our thinking and are (we believe)
experimenting in their R&D Lab. But most large companies take years, and
NOTE THE APPEARANCE OF PHOTOS OF BEARINGS
often the results never reach the Decision Makers. The Chief Engineer of this
USED IN THE ENGINE TRIALS
R&D thought that the Flex-Hone process also DEBURRED the INTERSECTS
OF THE CROSS HATCH FINISH, AND STRESS- RELIEVED THE METAL AT
THIS POINT OF INTERSECTION. THINK ABOUT IT. We are not bearing
manufacturers, but we have learned a little about surface finish.

Bearing from “C” engine No. 2 cylinder

taken after 24 hour run. All “C” Engine
bearings were Flex- Honed first for 12
strokes with 320 AO.

Notice absence of scoring and wear and

appearance of original Flex-Hone finish.

Bearing from No. 2 cylinder “A” engine

after 24 hour run. An OEM new bearing
such as were used in all the trials. Similar
effects will be noted on all bearings as
shown on the next page.

20
 Flex-Honed Finish is easy to distinguish.
Both from No. 2 cylinder assembly after
the 24 hour run. “C” test on top and
“A” below.

Original Flex-Honed Finish looks the same as O.E.M. set from “A” No. 2. The appearance
before the 24 hour run. “C” No. 2. does not leave much choice, does it?

NOW, LET US RECONSIDER THE OIL ANALYSIS

Wear elements of metal indicate engine condition. Iron from cylinder wails shows up in high levels during ‘’break-in’ ‘and then falls back as wear is stabi-
lized. Nickel is found in valve stems and crankshafts. (of which all above tests showed a minus-trace), and when combined with copper, tin and lead can
be an indicator of serious bearing and crankshaft wear. Nickel, without the other three, indicates the need of a valve job. Chromium may indicate rings and
cylinder wall. Lead, copper and tin are common bearing metals known as ‘’babbit’’. High readings can mean loss of an engine. Aluminum is used in some
blocks and pistons. Oil analysis is readily available, is inexpensive and is a clue to many problems.

The relationship of the metal traces indicated in the OiI Analysis shown on page 3 and the appearance of the wear factors on the bearings above now
becomes evident. Here is a WHOLE NEW FIELD for the S.A.E. to study and perhaps the President should appoint a committee.

The Flex-Hone is patented or has patents pending and the trademarked name of Flex-Hone is registered or has registations
pending in all the major countries of the world.
Some of the subject matter disclosed in this brochure is considered proprietary information and data is covered by pending
patent applications.

21
 PISTON RINGS
THE CRITICAL ASPECT OF COMPATIBILITY WITH BORE SURFACES

Piston Ring Manufacturers normally have no control over cylinder wall equipment ring with its peaky finish. Cylinder No. 4 was an OEM ring set
finishes, but try and develop a ring to meet an engine manufacturer’s which we lapped in by hand, and feel that we did not do the job properly
specifications. Many different shapes barrel faced, positive twist, reverse because of lack of proper equipment. It was lapped in on a used cylinder by
twist, head land, etc., designs have been produced from grey iron to ductile hand using an abrasive slurry. We could have lapped it unevenly and also
iron from thicknesses of 1/8 inch down to 1/16th inch, with some chrome out of round. I think the results will support these suppositions.
faced, chrome sided, treated with molybdenum and other hard facing materi-
als, and experiments with exotic materials. Some of these changes were The average compression reading taken at the end of the test run were
undoubtedly made for economy and speed in the manufacture of the rings higher on this ‘’C’’ test than on A, B, or D. The C- 1 cylinder (pre-run ring)
and the pistons to house them. Positive and Reverse twists were intended gave us the highest reading of the test (169.5 psi). The C-2 cylinder
to provide seals against blow-by and oil, but few took into consideration the (Hastings lapped) was second with C-3 (OEM ring) being third and C-4 (our
damaging abrasive punishment given to them in the ring-seating process lapped ring) being 4th. The average compression reading was 150 for ‘’A’’
while the peaky finish normally found in a rigid honed cylinder is worn down engine; 154.6 “B,” 161.3 for “C” with FH finish and modified rings; and
to develop the plateaued finish that will produce firing heading’s. Usually 161.2 for “D” engine with FH cylinders and oem rings.
the rings also have this peaky finish, and in the case of the ‘‘moly’’ not only
is it peaky but also hard, so that the attrition of the peaked finish on both One test is not conclusive by any means but might point out a direction we
cylinder and ring will equalize to end up with a plateau on both metal faces. should explore further. We noticed for example the No. 1 cylinder on each
engine test had a better compression test than the others. Perhaps the
It is our contention that with a plateaued finish on a cylinder wall surface combustion area was different, or perhaps other factors unknown. That is
such as that produced with a Flex- Hone, the peaky finish on a ring was not why we averaged the combustions of each cylinder in comparing test results.
only unnecessary but undesirable and the ring face should also be plateaued. Actually the “D” engine with Flex-Honed cylinders and the peaky OEM rings
did as well as the ‘’C’’ with its modified rings on an average basis. And this
To try out our theory, on the ‘’C’’ Test run on the VW engine, we had various is contrary to our firm belief. Perhaps this may be a challenge to an engine
modifications of rings. First the cylinders were plateau finished with the builder and his piston ring manufacturer.
Flex- Hone.
Barrel shaped rings and the positive and reverse twist rings are tapered on
Cylinder No. 1 was fitted with pre-run rings that had been used in ‘’A’’ test. their upper edges for various good reasons in today’s way-of-doing-things.
This ring was plateaued from the first test and we really expected great However, it occurs to us that the gas pressures on these tapered edges
things from it, providing the ring gap had not been increased too much from would force the ring inwards and if so would lessen ring pressure against
its first run. Cylinder No. 2 had a Hastings Piston Ring Set in which we had the walls and even might be the cause of partial ring-collapse: Instead of
asked Hastings to lightly lap the peaked finish to a plateau. This ring set was bedding in the rings through attrition does it now seem possible that we can
lapped but not down to the plateau wanted. Cylinder No. 3 was an original have this ‘’finished’’ condition to start with?

22
 SURFACE FINISHING OF
HYDRAULIC/PNEUMATIC CYLINDER WALLS
The problems surrounding obtaining the wall finish which is required on any 10 to 15 microinch CLA (or .25-.28 µ) both for a hydraulic and pneumatic
pneumatic or hydraulic cylinder is extremely complex and certainly cannot cylinder with one of the more popular and standard neoprene or butyl cup
be answered with any one particular formula. The cylinders themselves may seals. It Is also generally considered that any finish above 30 microinch CLA
be made of regular gray cast iron or instead they may be alloy steel, brass, (.76 µ) is too rough and will cause leaking and premature wear of the curls
stainless, chromed or they may be one of hundreds of different types of with a shortening of cycle life.
aluminum alloy each one with its different characteristics which need special
consideration in the treatment. We must also take into account the types of There is great similarity between the finishes required in hydraulics/pneu-
piston seals that are used. We may have leather, we may have some form matics and what we find in the combustion engine whereby we do require
of natural rubber, neoprene, butyl, nitrile, ethylene-proplene, silicone etc. and need a plateaued finish of anywhere from 60-80% of the cylinder wall
cups or pistons with “0’’ rings or pistons without any rings whatsoever which area. We do require valleys for oil retention and a fine cross hatch has also
depend upon a lap fit with possible oil grooves in the piston themselves. been highly recommended and has been found to be a great aid in the
Instead of the “0’’ rings they may even have piston rings similar to the spreading of the lubrication and prevention of seizure.
combustion engine. Plateaued finish is extremely important because it in- creases the bearing
area. We are all aware that the pressure per square inch on the cup against
In the overall determination as to exactly the finish you may require on the wall is going to vary directly with the amount of bearing area of the cup
your cylinder wall, we must also take into account the type of power that to the wall.
is going to be used whether it is powered by air or by a hydraulic fluid and
the quality of this power. ls the air going to be completely dry or is it going Another Item of extreme importance is to make sure that we have a burr-
to contain a lot of moisture and if it is going to contain a lot of moisture free surface particularly in the through-hole ports. As a matter of economy
then perhaps the cylinder wall should be bronzed In order to eliminate the many small hydraulic cylinders are roller-burnished which does have the
rust factor. If hydraulic fluids are going to be used, how good and how advantage of very quickly and inexpensively developing a very tiny finish In
pure and what specifications is the fluid going to be? Is it going to contain the cylinder and being able to roll that cylinder out to a desired diameter.
contaminants which may affect the seals that are used or may cause rust or Roller burnishing, however, has its drawbacks In the finish that it imparts
corrosion of the cylinder wall and also what must be taken into account is on the wall, because It takes the peaks of the finish that is left there after
the amount of pressure that is going to be applied to operate this cylinder. the boring operation, and folds them down into the valleys and this metal
All of these factors are extremely significant and all of them must be taken may break loose during the roller burnishing and forced into other parts of
into account in determining what is going to be the optimum for your unit. the surface. These peaks that are distorted may also break Boone and get
The things that we are really looking for, of course, is primarily the sealing into the hydraulic system after the cylinder Is fully assembled. As there are
characteristics and also in being able to obtain the maximum number always voids in the metal, the roller burnishing operation will produce very
of cycles before failure of your seal, and tests should be conducted very sharp burrs on the edge of these voids which causes an excessive wear on
definitely to determine the number of cycles that different finishes will give the cups and shortens the cycle life considerably. Some of the major manu-
you to determine the most life that can be obtained from your hydraulic unit facturers that are roller- burnishing are Flex-Honing their cylinders before the
before rebuilding Is necessary. roller-burnishing operation in order to remove these high peaks and some of
them are even lightly honing their Cylinders before and after roller-burnishing
The general consensus of opinion that we have received from the industrial operation first to remove the high peaks and develop a plateaued finish then
trade is that the finish of less than 5 microinch CLA (or| .13 µ) is not roller-burnishing and a final Flex-Honing to give the desired microinch finish
satisfactory because the wall is too smooth and there will be insufficient to the cylinder itself. A flexible type cylinder hone will, In one operation,
lubrication underneath the seal which may cause seizure or weeping and deburr the ports and deburr the finish by removing the high peaks off the
failure. The generally accepted and recommended finish runs anywhere from wall itself and create the necessary plateaued area and develop the required
microinch finish.

If surface scratches (peaks and valleys) are sharp, elastomer may

not be able to conform to the irregularities, permitting leakage.
Sharp scratches also cause accelerated abrasion wear. Elastomer
easily conforms to surface with smooth, rounded peaks and valleys.

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 TESTIMONIALS:
As an adjunct to the following UK Situation Report, we want to add one of the many success stories reported to us. Such reports and new-application infor-
mation are documented in our Monthly Sales Bulletins which now reaches its 114th issue.
Dear Mr. Nichols, 16 January 1978.
Your Ref.
Our Ref. DJA/aa.

l25cc YAMAHA SPRINT MOTORCYCLE

About a year ago I purchased a Flexhone to assist in the preparation of the
above engine for a record attempt at the Elvington meeting, held in July 1977.
I Was fortunate enough to be able to secure the 125cc class flying quarter-
mile British record with a two-way average speed of 119.5mph (with a fastest
one-way speed of l28.9mph and using 14,600rpm maximum on all runs). I believe
that the use of the Flexhone was a material factor in this, since I found
that the pistons and rings bedded down almost immediately and that the engine
temperature was lower (for a given ignition and carburetted settings). I also
found that even in this case, where the bore was hard chrome, piston scuffing
was eliminated under these most arduous conditions, ie. no grunting Inc was
required for the pistons and rings - none! London were OHW.

If it is of any use, you have my permission to show the contents of this

letter to your inquirers, to whom I must say that I have no connection with
your organization other than as a satisfied customer.

Yours Sincerely,

D J Armstrong
C Eng,MIMechE.
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 SITUATION REPORT:
FLEX-HONE IN THE UNITED KINGDOM AND IRELAND

The Flex-Hone was introduced to the U.K. and Ireland in November 1970. Group, National Coal Board, Sperm Vickers, Vickers Hydraulics, Teiehoist,
By November it had been tested and made approval by Perkins. In 1971 Rubery Owen, Burman & Sons, Cam Gears, Desoutter, Hamworthy, Gullick
further service approvals were issued by Massey Ferguson, Chrysler Europe & Dobson, Dobson Park Industries, Kango, Rutter Templair, Westinghouse
and Ford Europe. Subsequently, service approvals have been issued by Brit- Brake & Signal, Atlas, Copco, Compair, British Aluminum, Schrader, Kismet
ish Rail, Ruston Diesels, David Brown Tractors, J . 1. Case, A.E.C. and Dynaflex, Lucas Group, G.K.N. Birfield, Renold Group, Chloride,
J.C.B. Excavators. In 1972 Cosworth Engineering Limited, builders of the each, etc.
famous Ford DFV of Grand Prix racing engine which has won 102 Grand
Prix since it was introduced in 1967, adopted the Flex-Hone for their engine The Flex-Hone has now been adopted by the Nuclear Industry for fine sur-
cylinders and many other bores in the block (tappet blocks, oil ways etc.). face finishing of stainless steep tubing and other materials. Vickers Nuclear,
Lotus, Brabham, Maclaren, March, Elf Tyrell, Swindon Racing Engines, Rolls Royce Nuclear and G.E.C. are all customers in this field, as consistent
Broadspeed, Hesketh, Team Suttees, Frank Williams Racing, David Purley debris free finishes are a prime requirement in this market. Babcock &
LEC Racing Team and many others in the racing world all use Flex-Honed Wilcox, one of the biggest makers of electricity generating station boilers
engines or use the Flex-Hone in their own workshops. have been users of the Flex-Hone for some years for improving the surface
finish of boiler components prior to welding.
British Rail issued an instruction to all British Rail workshops to use the Flex-
Hone on their English Electric and Sulzer engines after exhaustive tests over Most British based lubricating oil research centers such as Lubrizol, B.P.,
four years. They proved that the period between substantially increased Shell Research, Amoco and Duckhams use the Flex-Hone for finishing
since adopting that the rings bed in faster and last longer. There has been cylinders in their research engines. Air-force, Army, and Naval Establishments
a parallel benefit in improved oil consumption. Most operating companies throughout the U.K. use the Flex-Hone but details of usage are classic fed.
within the National Bus Company use the Flex-Hone for engines and air The oil industry and petro-chemical industries find the Flex-Hone a superb
brake compressors. It is used by British Leyland, Rover, Triumph, Vauxhall maintenance tool which achieves the desired result but also because the tool
Bedford (G.M.C.), Rolls Royce Motors Limited, National Carriers, British Road is portable, i.e. the tool can be easily taken to the work whereas the work
Services, London Transport and many large U.K. haulage fleet operators. cannot always be taken to the tool. We list Imperial Chemical Industries
(I.C.I.) among our many customers.
In 1972 the Flex-Hone was introduced into the industrial market, i.e. to
manufacturing organizations who use the Flex-Hone as part of a manufactur- In the marine engine field the Flex-Hone market has been opened up as a
ing process. The Flex- Hone has been particularly successful in the hydraulics result of service approvals from Pilestick and Ruston Diesels. Again the por-
and pneumatics market because air compressors and hydraulic cylinders tability of the Flex- Hone is so important as the tool can be carried on board
all require plateau finishes because any form of debris on the cylinder wall ship and cylinder maintenance done in situ. We list P & 0, Esso, Texaco,
surface is just as damaging in these applications as in internal combustion Jebsons, Denholm & Maclay, Scottish Ship Management, Humber Tugs and
engines. Typical applications are: Boston Deep Sea Fisheries among our customers in this growing market.

Air Compressors
Hydraulic Ram Cylinders
Hydraulic Spool Valve Bodies
Hydraulic Motor Bodies (as reported by Peter Nichols, mgn. dir. NICRO (L) Ltd Fromehall Mi!I,
Pneumatic Cylinders Lodgemore Lane, Stroud. Glob., England GL5 3GH), exclusive distributor for
Compressed Air Tool Bodies the UK)
Brake Cylinders (wheel)
Clutch and brake master cylinders
Our customers in this field include Girlings, Automotive Products, Dotty

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 FLEX-HONE MACHINE DEVELOPED FOR PRODUCTION HONING ON NEW ENGINES

26
MACHINE DEVELOPED FOR FLEX-HONE USE ON NEW 2-CYCLE ENGINES. HOLDING FIXTURE LOCATES CYLINDER ON DOWEL PINS AT BASE
FOR ALIGNMENT WITH FLEX-HONE. POWER STROKING AND ROTATION ARE AUTOMATICALLY CONTROLLED THROUGH FIXTURE BASE.

MACHINE DEVELOPED FOR PRODUCTION HONING OF 12” TO 20” (305 TO 508 MM)
HYDRAULIC CYLINDER BORES USING GBDX FLEX-HONE

27
B R U S H
R E S E A R C H
M A N U F A C T U R I N G
C O . ,
I N C

BRUSH RESEARCH MANUFACTURING CO., INC.

. .
4642 East Floral Drive, Los Angeles, California 90022 P: 323.261.2193 F:323.268.6587
. .
E-Mail sales@brushresearch.com www.brushresearch.com www.flex-hone.com
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