TM 5-3820-245-14&P
FOUR VALVE CYLINDER HEADS
6. Remove the feeler gage. Hold the push rod
with a 5/16" wrench and tighten the lock nut with a "
wrench.
7. Recheck the clearance. At this time if the
adjustment is correct, the .025" gage will pass, freely
between the end of one valve stem and the rocker arm
bridge hut the .027" gage will not pass through.
Readjust the push rod, if necessary.
8. Check and adjust the remaining exhaust valves,
in the same manner as above.
Valve Clearance Adjustment (Hot Engine)
Maintaining normal engine operating temperature is
particularly important when making the final valve
Fig. 2 - Adjusting Valve Clearance (Four-Valve Cylinder
clearance adjustment. If the engine is allowed to cool
Head)
off before setting any of the valves. the clearance,
when running at full load, may become insufficient.
Valve Clearance Adjustment (Cold Engine)
1. With the engine at normal operating
1. Remove the loose dirt from the valve rocker
temperature (160-185F or 71-85'C), recheck the
cover(s) and remove the cover(s).
exhaust valve clearance with feeler gage J 9708-01. At
this time, if the valve clearance is correct. the .023"
2. Place the governor speed control lever in the
gage will pass freely between the end of one valve stem
idle speed position. If a stop lever is provided, secure it
and the rocker arm bridge, but the .025" feeler gage will
in the stop position.
not pass through. Readjust the push rod, if necessary.
3. Rotate the crankshaft. manually or with the
2. After the exhaust valve clearance has been
starting motor.
until the injector follower is fully
adjusted, check the fuel injector timing.
depressed on the cylinder to be adjusted.
Check Exhaust Valve Clearance Adjustment
NOTE: If a wrench is used on the crankshaft
bolt at the front of the engine, do not turn
1. With the engine operating at 100' F (38- C) or
the crankshaft in a left-hand direction of
less, check the valve clearance.
rotation as the bolt may be loosened.
2. If a .026" feeler gage (J 9708-01) .006" will
4. Loosen the exhaust valve rocker arm push rod
pass between the valve stem and the rocker arm bridge.
lock nut.
the valve clearance is satisfactory. If necessary adjust
the push rod.
5. Place a .026" feeler gage (J 9708-01) between
the end of one exhaust valve stem and the rocker arm
bridge (Fig. 2). Adjust the push rod to obtain a smooth
pull on the feeler gage.
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