DETROIT DIESEL 53
Valve Operating Mechanism 1.2.1
Inspection
Wash the rocker arms, rocker arm shaft and brackets thoroughly in clean fuel oil and dry them with compressed air.
Make certain that the oil passages in the rocker arms, rocker arm shaft and bracket bolts are open and clean.
Inspect all of the parts for excessive wear.
The maximum clearance between the rocker arm shaft and the injector rocker arm bushing or an exhaust valve rocker
arm (which has no bushing) is .004 " with used parts.
Examine each rocker arm pallet (contact face) for wear or galling. Also check the contact surfaces of the exhaust valve
bridge (four valve cylinder heads).
Remove Cam Follower and Push Rod Assembly (Cylinder Head Removed from Engine)
With the cylinder head removed from the engine, remove the cam followers as follows:
1. Rest the cylinder head on its side and remove the two bolts and lock washers securing the cam follower guide to the
bottom of the cylinder head (Fig. 2). Remove the guide.
2.
Pull the cam followers from the bottom of the cylinder head.
3.
Remove the fuel pipes from the injector and the fuel connectors.
4.
Loosen the lock nuts at the upper end of the push rods and unscrew the push rods from the rocker arm clevises.
5.
Pull the push rod and spring assemblies from the bottom of the cylinder head.
6. Remove the push rod lock nut, upper spring seat, spring and lower spring seat from each push rod for cleaning and
inspection.
The push rod spring seat retainers remain in the cylinder head. If the head is to be changed, these retainers must be
removed and installed in the new head.
Remove Cam Follower and Push Rod Assembly (Cylinder Head Not Removed from Engine)
A push rod, push rod spring, spring seats and cam follower may be removed from the top of the cylinder head by using
tool J 3092-01 as shown in Fig. 3.
1.
Clean and remove the valve rocker cover.
2.
Remove the fuel pipes from the injector and the fuel connectors.
3. Remove the rocker arm brackets and rocker arm shaft as outlined in
Steps 3 and 4 under Remove Rocker Arms and Rocker Arm Shaft.
4. Loosen the lock nut at the upper end of the push rod, next to the clevis,
and unscrew the rocker arm from the push rod to be removed. Remove the
lock nut from the push rod.
5. Install the remover J 3092-01, a flat washer and nut on the push rod (Fig.
3). Screw the nut down on the end of the push rod to compress the push rod
spring.
6. Remove the retainer from the cylinder head with a screw driver or similar
tool as shown in Fig. 3.
7. Unscrew the nut at the outer end of the push rod, thus releasing the
spring.
8. Pull the push rod, spring, spring seats and cam follower out through the
top of the cylinder head.
Fig. 6 - Former and Current Cam Followers
July, 1972
SEC. 1.2.1
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