Front Cover And Oil Filler Tube - Hummer H1 Service Manual

____________________________________________________________________
®
CAMSHAFT, TIMING CHAIN, SPROCKET, AND
DRIVE GEAR SERVICE
Clean the camshaft and geartrain parts in solvent. Wipe the
cam dry with shop towels only. Compressor can be used to dry
the other parts.
Inspect the cam bearing journals for wear, scoring, scuffing, or
discoloration from overheating. Replace camshaft if damaged
or discolored (Figure 2-128).
Inspect oil pump drive gear on camshaft for damage. Replace
camshaft if gear teeth are worn, chipped, or broken.
Measure bearing journal wear. Journals 1, 2, 3, and 4 should be
2.164-2.166 in. (54.975-55.025 mm). Journal 5 should be
2.007-2.009 in. (50.975-51.025 mm).
Mount the camshaft on "V" blocks and measure lift. Lift for
both intake and exhaust valve lobes should be 0.281 ± 0.002 in.
(7.133 ± 0.050 mm). Replace camshaft if any lobe is worn be-
low specified range.
Inspect both sprockets for cracks, or chipped, broken teeth. Re-
place sprockets as a matched set if either one is damaged.
Inspect the timing chain for distortion, stretch, or binding. Re-
place the chain if damaged.
Inspect the fuel injection pump drive and driven gears for
cracks, chipped or broken teeth, and wear. Replace both gears
as a set if either one is damaged.
Inspect the thrust plate and spacer for wear. Replace either part
if damaged or worn.
INJECTION PUMP
DRIVEN GEAR
CAMSHAFT SPROCKET
TIMING CHAIN
INJECTION PUMP
DRIVE GEAR
LOBE
Figure 2-128: Camshaft and Geartrain
05745159
THRUST PLATE
SPACER
CRANKSHAFT
SPROCKET
CAMSHAFT
JOURNAL
OIL PUMP
DRIVE GEAR

FRONT COVER AND OIL FILLER TUBE

Inspect the cover for cracks, scratches/nicks on the sealing sur-
faces, or damaged threads. Remove minor scratches/nicks with
180 grit emery. Repair thread damage with helicoil inserts. Re-
place part if damaged (Figure 2-129).
Inspect the adapter plate for cracks, scratches on mating and
sealing surfaces, dents, pitting, and corrosion. Repair minor
scratches with 180 grit emery. Replace the plate if cracked or
bent.
FRONT
SEALING
SURFACE
Figure 2-129: Front Cover Inspection Points
Inspect the oil filler tube grommet. Replace the grommet if
cracked, brittle, or loose (Figure 2-130).
Inspect the oil filler tube. Replace the tube if cracked or dis-
torted (Figure 2-131).
Inspect the filler cap sealing gasket. Replace the cap if the gas-
ket is missing or damaged. Replace the cap if damaged.
ADAPTER PLATE
OIL FILLER
TUBE GROMMET
FRONT SEALING SURFACE
Figure 2-130: Adapter Plate Inspection Points
Engine 2-71
REAR
SEALING
SURFACE
THREADED
HOLES
REAR
SEALING
SURFACE