1.2.1 Valve Operating Mechanism
DETROIT DIESEL 53
.010" diametric clearance exists, replace the cam
4. Prior to installing a new roller and- pin, remove any
follower assembly or install a new cam roller and pin,
burrs on the surfaces of the cam follower at the pin
which are serviced as a set. Be sure the follower legs
holes.
are beveled (Fig. 6) and check the total side clearance
between the roller and follower; this clearance must not
5. Position the follower body in the groove of the fixture
be less than .015 " nor more than .023 ".
with the proper size fixture plunger extending through
the roller pin hole in one of the legs of the follower body.
Oversize roller and pin sets are available for service
when required. However, DO NOT attempt to bore out
6. Position the-roller in the cam follower body (Fig. 7).
the legs of a standard cam follower for an oversize roller
The small plunger in the tool will align the roller with the
and pin set. This cannot be over emphasized because
pin holes in the follower body.
of the extremely close manufacturing tolerances.
7. Align the pin with the hole in the follower body and
Remove and Install Cam Follower Roller and Pin
carefully drive the pin into the body until the ends of the
pin are centered in the legs of the body.
1. Clamp fixture J 5840 securely in a vise as shown in
Fig. 7 and place the cam follower in the groove in the
8. Check the side clearance between the roller and the
top of the fixture with the follower pin resting on top of
follower body. This clearance must be .015 " to .023 ".
the corresponding plunger in the fixture.
Install Cam Follower and Push Rod Assembly
2. Drive the pin from the roller with a suitable drift.
Exercise caution in removing the cam follower body and
(Cylinder Head Removed from Engine)
roller from the fixture as the follower pin is seated on top
of a spring-loaded plunger in the fixture body.
1. Install a serrated lower spring seat on each push rod.
3. Before installing the new roller and pin kit, remove
2. Place the push rod springs (Fig. 11) on the push
the preservative by washing the parts with clean
rods.
lubricating oil or Cindol 1705. Do not use fuel oil.
3. Install the upper spring seat on each push rod.
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 100-125F.) 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
Fig. 11. - Push Rod Spring Identification
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.
1972 General Motors Corp.
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