Cleaning and Inspection - TM-10-3930-634-340074

TM 10-3930-634-34

wear. Inspect push rods for bent condition. Replace a

defective push rod.

(5) Inspect the push rod springs for damage.

Check the push rod spring tension. Use a spring tester

to check the push rod spring load. Replace the spring

when a load of less than 250 lbs. will compress the

spring to a length 2-9/64 inches.

(6) Inspect the cam follower holes in the cylinder

head to make sure they are clean, smooth and free of

score marks.

(7) Check the follower to cylinder head clearance.

The clearance must not exceed 0.006 inch with used

parts. Inspect the cam follower roller to make sure it

turns smoothly and freely on its pin, and that the

roller is free from flat spots or scuff marks. If the

roller is damaged, then inspect the cam lobe on which

it operates.

(8) Refer to figure 3-64 and check the clearance

between the cam roller and follower and the clearance

between the roller bushing and pin. If the clearance is

excessive replace the cam follower or install a new roll-

er follower set. When replacing a cam follower or in-

stalling a new roller set make sure the follower legs are

beveled.

CAUTION

Do not attempt to bore out the legs of a stand-

ard cam follower for an oversize roller and

pin set. This cannot be over emphasized be-

cause of the extremely close manufacturing

tolerances.

NOTE

Cam follower assemblies with letter "S"

(a) Remove push rod locknut (fig. 3-62). Install

stamped on the end of the roller, pin, and on

push rod remover tool on push rod with flatwasher and

the leg of the cam follower body are equipped

reinstall lock nut, tightening the lock nut until the

with oversize roller and pin sets.

cam follower spring is compressed.

(9) Remove and install the cam follower roller and

(b) Remove push rod retaining ring (fig. 3-62).

pin as follows:

(c) Pull the push rod and cam follower from the

(a) Clamp fixture securely in a vise as illustrated

bore in the cylinder head.

in figure 3-65 and place the cam follower in the

(d) Remove the lock nut, tool and flatwasher

groove in the top of the fixture, with the follower pin

from the push rod.

resting on top of the corresponding plunger in the fix-

c. Disassembly. Disassemble the rocker arms, in-

ture.

jector arm, push rod and cam follower in numerical se-

(b) Use a suitable drift and drive the pin from

quence illustrated on figure 3-63.

the roller. Exercise caution in removing the cam fol-

d. Cleaning and Inspection.

lower body and roller from the fixture as the follower

(1) Clean all parts with cleaning solvent (Fed Spec

pin is seated on top of a spring loaded plunger in the

P-D-680) and dry thoroughly. Make sure all oil

fixture body.

passages in the rocker arms, rocker arm shafts and

(c) Prior to installing a new pin, remove any

bracket bolts are open and clean.

burrs on the surface of the cam follower at the pin

(2) Inspect all parts for excessive wear or other

holes.

damage.

(d) Position the follower body in the groove of

(3) Measure the clearance between the rocker arm

the fixture with the proper size fixture plunger extend-

shaft and the injector rocker arm bushing. Measure

ing through the roller pin hole in one of the-legs of the

the clearance between the rocker arm shaft and the ex-

follower body.

haust rocker arm (which has no bushing). The maxi-

(e) Coat the new roller bushing and pin with

mum clearance is 0.004 inch with used parts.

lightweight engine oil.

(4) Inspect rounded end of push rods for excessive

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