C6.
6 Industrial Engine 66600001-UP(SEBP4314 - 22) - Document Structure Page 1 of 5
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Product: INDUSTRIAL ENGINE
Model: C6.6 INDUSTRIAL ENGINE 666
Configuration: C6.6 Industrial Engine 66600001-UP
Testing and Adjusting
C6.6 Industrial Engine
Media Number -SENR9968-02 Publication Date -2007/05/01 Date Updated -2007/05/11
i02656276
Engine Valve Lash - Inspect/Adjust
SMCS - 1102-025
Table 1
Required Tools
Tool Part Number Part Description Qty
A 228-3610 Angled feeler gauge 1
Illustration 1 g01334425
Cylinder and valve location
(A) Exhaust valve
(B) Inlet valve
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C6.6 Industrial Engine 66600001-UP(SEBP4314 - 22) - Document Structure Page 2 of 5
If the valve lash requires adjustment several times in a short period of time, excessive wear exists in a
different part of the engine. Find the problem and make necessary repairs in order to prevent more damage to
the engine.
Not enough valve lash can be the cause of rapid wear of the camshaft and valve lifters. Not enough valve lash
can indicate that the seats for the valves are worn.
Valves become worn due to the following causes:
Fuel injection nozzles that operate incorrectly
Excessive dirt and oil are present on the filters for the inlet air.
The load capacity of the engine is frequently exceeded.
Too much valve lash can cause broken valve stems, springs, and spring retainers. This will produce emissions
in excess of the correct specification.
Too much valve lash can be an indication of the following problems:
Worn camshaft and valve lifters
Worn rocker arms
Bent pushrods
Broken socket on the upper end of a pushrod
Loose adjustment screw for the valve lash
If the camshaft and valve lifters show rapid wear, look for fuel in the lubrication oil or dirty lubrication oil as
a possible cause.
Valve Lash Check
An adjustment is not necessary if the measurement of the valve lash is in the acceptable range. Check the
valve lash while the engine is stopped. The temperature of the engine does not change the valve lash setting.
If the measurement is not within the acceptable clearance, adjustment is necessary. Refer to "Valve Lash
Adjustment".
Valve Lash Adjustment
Table 2
Inlet Valves Exhaust Valves
Valve Lash 0.35 ± 0.05 mm (0.0138 ± 0.0020 inch)
0.35 ± 0.05 mm (0.0138 ± 0.0020 inch)
Firing Order 1-5-3-6-2-4 (2)
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C6.6 Industrial Engine 66600001-UP(SEBP4314 - 22) - Document Structure Page 3 of 5
(2) The No. 1 Cylinder is at the front of the engine.
Note: For new engines, the valve lash should be checked and reset after the first 500 hours and after the next
500 hours. The valve lash will then be checked at service intervals of 1000 hours.
Note: For example, if the pushrods in a remanufactured engine have been replaced with new parts then adjust
the valve lash to 0.25 ± 0.05 mm (0.0098 ± 0.0020 inch) for the initial rebuild. The tappets should be reset to
0.35 ± 0.05 mm (0.0138 ± 0.0020 inch) at the normal service intervals thereafter.
Illustration 2 g01334426
Setting the valve lash
(A) Angled feeler gauge
(1) Adjustment screw
(2) Locking screw
Accidental engine starting can cause injury or death to personnel.
To prevent accidental engine starting, turn the ignition switch to the
OFF position and place a do not operate tag at the ignition switch
location.
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C6.6 Industrial Engine 66600001-UP(SEBP4314 - 22) - Document Structure Page 4 of 5
Illustration 3 g01334427
1. Remove the valve mechanism cover. Refer to Disassembly and Assembly, "Valve Mechanism Cover -
Remove" for the removal procedure.
Note: When the valve mechanism cover is removed or installed, the electrical harness must be checked.
Do not trap the injector harness when the valve mechanism cover is installed. Do not allow the harness
to be in contact with the valve mechanism cover. Renew the harness, if the harness is damaged.
Table 3
Set valve lash for the following :
Rotate the crankshaft until inlet valves are fully Inlet valves Exhaust valve
open. "(Cylinder "(Cylinder number)"
number)"
9 10
11
(5) (5)
5 6
3
(3) (3)
11 12
7
(6) (6)
3 4
1
(2) (2)
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C6.6 Industrial Engine 66600001-UP(SEBP4314 - 22) - Document Structure Page 5 of 5
7 8
9
(4) (4)
1 2
5
(1) (1)
2. See illustration 3. Rotate the crankshaft clockwise until the pair of inlet valves (11) is fully open.
Measure the valve lash on inlet valves (9) and exhaust valves (10) . If necessary, adjust the valve lash to
the settings in Table 3. Complete the sequence of checks according to Table 4 until all the cylinders
have been checked or adjusted.
a. Loosen the valve adjustment screw locknut that is on the adjustment screw (1) .
b. Place Tooling (A) between the rocker arm and the valve. Turn the adjustment screw (1) while the
valve adjustment screw locknut (2) is being held from turning. Adjust the valve lash until the
correct specification is achieved.
c. After each adjustment, tighten the valve adjustment screw locknut while you hold the valve
adjustment screw (1) . This will prevent the valve adjustment screw (1) from turning.
3. Complete the sequence of checks according to Table 4 until all the cylinders have been checked or
adjusted. Reinstall the valve mechanism cover. Refer to Disassembly and Assembly, "Valve
Mechanism Cover - Install" for the installation procedure.
Copyright 1993 - 2008 Caterpillar Inc. Mon Aug 25 16:20:55 UTC+0100 2008
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