Valve Rocker Arm Covers and Associated Parts

and move roller through the extremes of its

measurement (90 degrees) to first measurement.

travel. Check reading on the dial indicator.

Average the two measurements.

Limits should be 0.006L in. maximum. Mark

(b) Take two measurements of diameter

worn or damaged rollers and hubs for repair.

b o r e at bottom of ring travel. Measure diameter

o f bore approximately parallel to line of valves,

Inspect adjusting screws (36) for stripped or

d a m aged threads. Check screw by turing screw

a n d then take cross measurement (90 degrees) to

in and out of rocker arms. Screw must turn

first

measurement.

Average

the

two

f r e e l y . Check swivel pad on adjusting screw for

measurements.

free

rotation,

Mark damaged parts for

replacement.

flange-end average.

(3) V a l v e r o c k e r a r m s h a f t s . C h e c k v a l v e

(d) Compare the measurements taken 90

r o c k e r arm shafts (22 and 35) for cracks, nicks,

degrees apart. Each two measurements (top or

bottom) must be within 0.003 inches of each

scoring, or plugged oil passages. Check shafts

against limits specified in overhaul standards

o t h e r . If the difference exceed 0.003 inches, the

c y l i n d e r is out-of-round and must be marked for

(table 6-15). Replace unserviceable shafts.

(4) Valves.

repair.

(4) C a m s h a f t b e a r i n g s u r f a c e . I n s p e c t

(a) Valve head. C h e c k i n t a k e a n d e x h a u s t

cam shaft bearing surface for pitting, galling,

valve (11 and 12) for evidence of pitting, im-

burs, and nicks. Check bearing diameter, with

p e r f e c t seating, or warping on valve head. Heavy

rocker a r m cover installed, against limits

discoloration, burning, erosion, or a heavy

specified in overhaul standards (table 6-15).

c a r b o n deposit on valve face indicates a warped

valve. A l i g h t f r o s t e d a p p e a r a n c e o r m i n o r

(5) Cylinder exterior. I n s p e c t c y l i n d e r h e a d

discoloration on valve face does not indicate a

a n d barrel cooling fins for possible repair (para

warped or unserviceable valve.

6-33 f).

d. Valve Rocker Arm Covers and Associated

(b) V a l u e s t e m . I n s p e c t t h e v a l v e s t e m s

P a r t s . (Refer to fig. B-4)

a n d the locking groove in the stems for pitting,

(1) V a l v e r o c k e r a r m c o v e r . I n s p e c t v a l v e

scoring cracks, or damaged tips. Checks valves

against limits specified in overhaul standards

r o c k e r a r m c o v e r ( 3 9 ) f o r c r a c k s . Inspect

cam shaft bearing surface in cover for galling,

(table 6-15). Replace valves that are warped,

cracked, or unserviceable.

pitting, burs, and nicks. Check cover against

limits specified in overhaul standards (table 6-

(5) V a l v e springs. Inspect inner spring (18),

intermediate spring (17), and outer spring (16)

1 5 ) . Check valve adjusting cover plate (29) for

for wear, cracks, set, or other evidence of failure.

cracks and for warpage. Replace cylinder

C h e c k all springs against limits specified in the

assembly when cover is unserviceable.

overhaul standards (table 6-15).

(2) Valve rocker arms. I n s p e c t v a l v e r o c k e r

a r m s (33 and 34) for cracks, using a magnifying

(6) Valve spring retainers, valve rotors, and

l o c k s . Inspect valve spring retainers (19 and 38)

g l a s s and a strong light. Inspect the bushing-type

and intake valve spring seat (15) for wear and

bearings in the rocker arms for scoring and

cracks. Check exhaust valve rotor (40) by

s e c u r e fit. Check bearings against limits specified

r o t a t i n g inner section. Inner section must rotate

i n overhaul standards (table 6-15). Inspect valve

f r e e l y . Inspect rotor for wear or cracks. Inspect

r o c k e r arm rollers for scuff or score marks and

spring retainer locks for wear or cracks. Worn

for looseness on hub. Rotate roller and check

l o c k s will have ridges on top face. Replace any

clearance between roller and hub by mounting

unserviceable parts.

rocker arm securely in a soft-jawed vise. Set a

dial indicator against contact surface of roller

6-56