1.2.1 Valve Operating Mechanism
DETROIT DIESEL 53
.010 " diametric clearance exists, replace the cam follower assembly or install a new cam roller and pin, which are
serviced as a set. Be sure the follower legs are beveled (Fig. 6) and check the total side clearance between the roller and
follower; this clearance must not be less than .015 " nor more than .023 ".
Oversize roller-and pin sets are available for service when required. However, DO NOT attempt to bore out the legs of a
standard cam follower for an oversize roller and pin set. This cannot be over emphasized because of the extremely close
manufacturing tolerances.
NOTE: Cam follower assemblies with the letter "S" stamped on the end of the
roller, pin and on one leg of the cam follower body are equipped with oversize
roller and pin sets.
Remove and Install Cam Follower Roller and Pin
1. Clamp fixture J 5840 securely in a vise as shown in Fig. 7 and place the cam follower in the groove in the top of the
fixture with the follower pin resting on top of the corresponding plunger in the fixture.
2. Drive the pin from the roller with a suitable drift. Exercise caution in removing the cam follower body and roller from
the fixture as the follower pin is seated on top of a spring-loaded plunger in the fixture body.
3. Before installing the new roller and pin kit, remove the preservative by washing the parts with clean lubricating oil or
Cindol 1705. Do not use fuel oil.
4. Prior to installing a new roller and pin, remove any burrs on
the surfaces of the cam follower at the pin holes.
5. Position the follower body in the groove of the fixture with
the proper size fixture plunger extending through the roller pin
hole in one of the legs of the follower body.
6. Position the roller in the cam follower body (Fig. 7). The
small plunger in the tool will align the roller with the pin holes in
the follower body.
7. Align the pin with the hole in the follower body and
carefully drive the pin into the body until the ends of the pin are
centered in the legs of the body.
8. Check-the side clearance between the roller and the
follower body. This clearance must be .015 " to .023 ".
Fig. 11 - Push Rod Spring Identification
Install Cam Follower and Push Rod Assembly (Cylinder Head Removed from Engine)
1. Install a serrated lower spring seat on each push rod. If the engine being assembled was equipped with plain lower
spring seats, replace them with serrated spring seats (Fig. 8).
2.
Place the push rod springs (Fig. 11) on the push rods.
3. Install the proper upper spring seat on each push rod. The cup shaped spring seat used with the current type push
rod spring may also be used with the former spring.
4. Install the spring seat retainer in the cylinder head. Then slide the push rod, lower spring seat, spring and upper
spring seat as an assembly into the cam follower bore from the bottom of the cylinder head.
5. Screw the push rod lock nut down on the upper end of the push rod as far as possible. Then screw the push rod into
the clevis until the end of the rod is flush with or above the inner side of the clevis.
6. Immerse the cam follower assemblies in clean Cindol 1705 (heated to 100 -125 'F.) for at least one hour before
placing them in the cylinder head, to ensure initial lubrication between the cam follower roller pins and the roller
bushings. Rotate the cam follower roller during the soaking period to aid in purging any air from the bushing-roller area.
The heated Cindol 1705 results in better penetration as it is less viscous than engine oil and flows more easily between
the pin and roller bushing surfaces. After the cam follower is removed from the Cindol 1705, the cooling action of any
trapped air in the pin and bushing area tends to pull the oil into the cavity.
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