Engine Valve Lash - Inspect/Adjust - Perkins 1104D NH1 Systems Operation Testing And Adjusting

56
Testing and Adjusting Section
Engine Valve Lash -
Inspect/Adjust
Table 5
Required Tools
Part
Tool Number
27610298
A Angled feeler gauge
Illustration 53
Cylinder and valve location
(A) Exhaust valve
(B) Inlet valve
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.
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Part Description Qty
1
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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 6
Inlet Valves
0.35 ± 0.05 mm
Valve Lash (0.0138 ± 0.0020
inch)
Firing Order
(2)
The No. 1 Cylinder is at the front of the engine.
Note: When the engine is new, the valve lash should
be checked and reset after a service interval 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.
RENR7967
Exhaust Valves
0.35 ± 0.05 mm
(0.0138 ± 0.0020
inch)
1-3-4-2
(2)