Hummer H1 Service Manual page 109

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2-72 Engine
CAP
OIL FILLER TUBE
Figure 2-131: Oil Filler Tube and Cap
CYLINDER HEAD OVERHAUL
Disassembly
1. Remove glow plugs and injectors if not previously
removed.
2. Remove temperature sender from left side head
(Figure 2-132).
TEMPERATURE SENDER
Figure 2-132: Temperature Sender Removal/
Installation
3. Clean valve faces with wire brush and measure amount
valves are recessed in head with dial indicator. Intake
valves should be recessed approximately 0.001 in. (0.034
mm) and exhaust valves approximately 0.002 in. (0.048
mm). Recessing means valve faces are positioned below
cylinder head combustion chamber surface.
• If valves extend or protrude above chamber surface, en-
gine is equipped with wrong valves, or heads have been
mismachined.
• If valves are recessed to at least the stated values, con-
tinue with disassembly.
4. Remove valve assembly in sequence as follows:
a. Compress valve spring with compressor tool J–8062
(Figure 2-133).
b. Remove valve locks (Figure 2-134).
c. Release and remove compressor tool.
d. Remove valve retainer, shield and spring.
e. Remove stem seal from valve and slide valve out of
guide and head.
f. Remove shim.
g. On exhaust valve, also remove nylon stem and guide
seal (Figure 2-134).
h. Remove remaining valve assemblies in same manner.
i. Keep valve parts together on workbench or use
yardstick with drilled holes to keep valve assemblies
separate.
NOTE: Do not intermix the valve parts as intake and exhaust
valve are different. In addition, the exhaust valves have two
stem seals and a rotator style spring retainer.
Figure 2-133: Compressing Valve Spring
(to Remove Locks)
5. Mark position of pre-combustion chambers in each
cylinder head (Figure 2-135). Ideally, chambers (if
reused), should be installed in same location in head.
6. Remove prechambers from cylinder heads (Figure 2-135).
Use a round pry tool to loosen and start each chamber out
of seat in cylinder head.
7. Remove cover and gasket from right side head
(Figure 2-136).
®
VALVE
SPRING
COMPRESSOR
TOOL J–8062