Lifter, Pushrod, Rocker Arm Service; Damper And Flywheel Service - Hummer H1 Service Manual

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2-76 Engine

LIFTER, PUSHROD, ROCKER ARM SERVICE

Clean the rocker arms, shafts, pushrods, guides, clamps, and
lifters in parts cleaning solvent.
Immerse the lifters in solvent and use a pushrod to stroke the
lifter plunger. Replace any lifter that is collapsed, or if fluid
cannot be pumped out oil hole when plunger is stroked.
Inspect the lifter roller and bearings. Replace any lifter that ex-
hibits wear on the body, roller, or bearings. Turn the roller and
note action. Replace the lifter if the roller binds, or is seized.
Check each pushrod (Figure 2-144) for distortion and wear.
Replace any pushrod that is bent. Check the pushrod ball ends.
Replace the pushrod if either ball end is flattened, scored, or
loose.
Inspect the lifter guide plates and clamps (Figure 2-144). Re-
place the plates and clamps if worn, or distorted. Also make
sure the guide plates are a proper slip fit on the lifters.
Inspect the rocker arms and shafts for wear, cracks, scoring/
grooving, or distortion. Check the pushrod contact area on each
arm for wear, or scoring. Replace the rocker arms, or shaft as
needed.
Discard the rocker arm retainers (Figure 2-145). Also discard
the rocker shaft retainers if bent, distorted, or cracked.
Figure 2-144: Lifter and Pushrod Components

DAMPER AND FLYWHEEL SERVICE

The flywheel can be immersed in cleaning solvent. However,
the torsional damper should only be wiped clean with a cloth
wetted with parts cleaner. The damper has a rubber composite
insulator (Figure 2-146). This insulator can be damaged by im-
mersion in some cleaning solutions.
Inspect the damper insulator ring (Figure 2-146). Replace the
damper if the ring is cracked, distorted, protruding, or loose
GUIDE CLAMP
(hub can be turned independently of outer shell). Also check
the hub bore, keyway, and seal surface. Minor nicks or
scratches can be smoothed with 320 grit emery but replace the
damper if these surfaces are severely scored, or cracked. Clean
the bolt hole threads with a tap if necessary.
GUIDE PLATE
CAUTION: 6.5L diesel engines are externally balanced. The
torsional damper is an integral part of the balancing mecha-
nism. Never use a solid, or similar non-recommended damper
as this practice can result in a broken crankshaft. Use factory
replacement dampers only.
PUSHROD
Inspect the flywheel carefully (Figure 2-147). Look for worn,
chipped, or broken ring gear teeth and check the hub for cracks
at the mounting bolt holes. Place the flywheel on a flat surface
and check the body for warping, distortion, or cracks at the
converter attaching bolt holes. Replace the flywheel if it exhib-
its any of the foregoing conditions.
ROLLER LIFTER
NOTE: The ring gear is not serviced separately. It is only
available as part of a new flywheel.
ROCKER SHAFT
RETAINER AND BOLT
ROCKER ARMS
ROCKER ARM SHAFT
Figure 2-145: Rocker Arm and Shaft Components
®
ROCKER ARM
RETAINER