DETROIT DIESEL 53
ENGINES WITH FOURE VALUE CYLINDER HEADS
All of the exhaust valves may be adjusted in firing
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 (Cold
I. Remove the loose dirt from the valve rocker cover
and remove the cover.
2. Place the governor speed control lever in the idle
speed position. If a stop lever is provided, secure it in
the stop position.
Fig. 2 - Adjusting Valve Clearance (Four Valve Head)
3. Rotate the crankshaft, manually or with the starting
motor, until the injector follower is fully depressed on
the particular cylinder to be adjusted.
If a wrench is used on the crankshaft 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. Readjust the push rod, if necessary.
8. Adjust and check the remaining exhaust valves in the same manner as above.
Exhaust Valve Clearance Adjustment (Hot Engine)
Maintaining normal engine operating temperature is particularly important when making the final exhaust valve clearance
adjustment. If the engine is allowed to cool before setting any of the valves, the clearance, when running at full load, may
1. With the engine at normal operating temperature (160 °-185 ° F.), recheck the exhaust valve clearance with
feeler gage J 9708. At this time, if the valve clearance is correct, the .023 " gage will pass freely between
the end of one valve stem and the rocker arm bridge and the .025 " feeler gage will not pass through.
Readjust the push rod, if necessary.