14.1
DETROIT DIESEL 53
ENGINES WITH FOUR VALVE CYLINDER HEADS
bolt at the front of the engine, do not turn the
crankshaft in a left-hand direction of rotation
or the bolt may be loosened.
4. Loosen the exhaust valve rocker arm push rod lock
nut.
5. Place a .027 " feeler gage, J 9708, 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.
6. Remove the feeler gage. Hold the push rod with a
5/16 " wrench and tighten the lock nut with a 1/2 "
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 and the .027 " gage will not pass through.
Fig. 2 - Adjusting Valve Clearance (Four Valve
Readjust the push rod, if necessary.
Head)
8. Adjust and check the remaining exhaust valves in
All of the exhaust valves may be adjusted in firing
the same manner as above.
order sequence during one full revolution of the
crankshaft. Refer to the General Specifications at the
front of the manual for the engine firing order.
Exhaust Valve Clearance Adjustment (Hot
Engine)
Exhaust Valve Clearance Adjustment (Cold
Maintaining normal engine operating temperature is
Engine)
particularly important when making the final exhaust
valve clearance adjustment. lf the engine is allowed to
cool before setting any of the valves. the clearance.
1. Remove the loose dirt from the valve rocker cover
when running at full load, may become insufficient.
and remove the cover.
1. With the engine at normal operating temperature
2. Place the governor speed control lever in the idle
speed position. If a stop lever is provided, secure it in
with feeler gage J 9708. At this time, if the valve
the stop position.
clearance is correct, the .023 " gage will pass freely
between the end of one valve stem and the rocker arm
3. Rotate the crankshaft, manually or with the starting
bridge and the .025 " feeler gage will not pass
motor, until the injector follower is fully depressed on
through. Readjust the push rod, if necessary.
the particular cylinder to be adjusted.
2. After the exhaust valve clearance has been adjusted,
CAUTION: If a wrench is used on the crankshaft
check the fuel injector timing (Section 14.2).
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