TM 55-1930-209-14&P-21
5-65 Rocker arm and cam follower cleaning, Inspection, and repair
a. Rocker Arms
(1) Wash all parts thoroughly with cleaning solvent and dry thoroughly. Make sure oil passages In rocker
arms, rocker arm shafts, and bracket bolts are open and clean.
(2) Inspect all parts for excessive wear or other damage.
(3) Measure clearance between rocker arm shaft and Injector rocker arm bushing. Measure clearance
between the rocker arm shaft and exhaust rocker arm (which has no bushing). The maximum clearance Is 0.004 inch
with used parts and .0025 Inch for new parts.
(4) Inspect each rocker arm pallet at contact face for excessive wear or galling. Inspect contact surfaces of
exhaust valve bridge.
b. Cam Followers and Push Rods
(1) Proper cam follower inspection and service are necessary for continued efficient engine performance.
When any appreciable change In Injector timing or exhaust valve clearance occurs during engine operation, cam
followers and their related parts must be removed and inspected for wear. This change during engine operation can
usually be detected by excessive noise at idle speed.
(2) Wash all cam followers and related parts with cleaning solvent and dry thoroughly.
(3) Examine cam follower rollers (Figure 5-28), for scoring, pitting or flat spots. Rollers must turn freely on
their pins. Measure total diametric clearance and side clearance. Install a new roller and pin If clearances exceed those
specified.
NOTE
Cam follower assemblies stamped with letter "S" on the pin, roller and follower body are equipped
with an oversized pin and roller. The same clearances apply to both standard and large cam
follower assembly.
(4) Use a suitable light and examine camshaft lobes for scoring, pitting or flat spots. Bar engine over so that
all cam surfaces can be observed.
(5) Measure cam follower bores In cylinder head with a telescope gage and micrometer and record readings.
Measure cam followers with a micrometer and record data. Determine follower to bore clearances and compare them to
those specified In Table 1-1.
(6) Inspect push rods and spring seats for wear.
(7) Examine cam follower springs for wear and damage and check spring load.
5-75
