Inspection
1. Clean all parts in a non-volatile cleaning solution or solvent. Dry parts with low pressure compressed air.
2. See Figure 3-27. Check rocker arms (3) for uneven wear or pitting where contact is made with the valve stem tips. Check for concave wear where rocker arms contact the pushrod ends. Replace rocker arm if excessive wear is found.
3. Verify that oil holes in rocker arms and rocker arm support plate (5) are clean and open.
4. Inspect rocker arm shafts (4) for scratches, burrs, scoring or excessive wear. Replace as necessary.
Rocker Shaft Fit
1. See Figure 3-28. Measure the inside diameter of the rocker arm support plate bore.
2. See Figure 3-29. Measure the outside diameter of the rocker arm shaft where it fits in the bore.
3. Repeat the measurement on opposite side of support plate and shaft. Replace shaft or support plate if clearance
exceeds service wear limit of 0.0035 in (0.089 mm).
Rocker Arm Shaft to Bushing
1. Check rocker arm shaft to bushing fit.
a. See Figure 3-30. Measure the inside diameter of the rocker arm bushing.
b. See Figure 3-31. Measure the outside diameter of the rocker arm shaft where it rides in the bushing.
2. Repeat measurement on opposite side of rocker arm and shaft. Replace shaft or bushings if clearance exceeds
service wear limit of 0.0035 in (0.089 mm).
Replace Rocker Arm Bushings
NOTE
Bushing replacement and reaming must be done one at a time to achieve proper alignment. Follow all steps for one bushing and then repeat for the other bushing.
1. See Figure 3-32. Remove bushing from rocker arm:
a. Turn a 9/16-18 tap (2) into bushing until tight.
b. Place rocker arm under ram of arbor press with tap at bottom.
c. Slide a discarded rocker arm shaft (1) through open end of rocker arm until contact is made with tap.
d. Using shaft as driver (and untapped bushing as pilot), press against shaft until both tap and bushing are free.
2. See Figure 3-33. Using a suitable driver, press new bushing into side of rocker arm until flush with casting. Be sure to orient bushing so that split line faces top of rocker arm.
NOTE
Never back the reamer out of rocker arm or new bushing will be damaged.
3. Ream bushing:
a. See Figure 3-34. Lock rocker arm in a vise using brass jaw inserts or shop towels to prevent casting damage. Note that old bushing on drive side of reamer as pilot.
b. Rotate reamer until the new bushing on the far side is reamed.
c. Continuing in the same direction, draw drive side of reamer from new bushing.
4. Repeat steps to remove, install and ream second bushing.
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