Hummer H1 Service Manual page 75

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2-38 Engine
Cylinder Head (Left Side)
Installation
1. Clean gasket surface of cylinder block with scraper if nec-
essary. Then remove protective covering from cylinder and
lifter valleys.
2. Wipe cylinder block surface clean with solvent and cloth.
3. Position new head gasket on cylinder block. Be sure
gasket is aligned on cylinder block dowels.
CAUTION: Install the new gasket dry. Do not use any type of
sealer on the gasket. Sealer can prevent proper seating and re-
sult in coolant leaks.
4. Install cylinder head with aid of helper or with hoist. Be
sure head is properly seated on cylinder block dowels.
5. Install and tighten new cylinder head bolts as follows:
a. Apply light coat of Teflon Pipe Sealant (PST) to
threads and under heads of new bolts.
b. Install and tighten bolts to initial torque of 20 lb-ft (27
N¥m). Follow tightening sequence (Figure 2-42).
c. Tighten bolts to 50 lb-ft (68 N¥m) torque evenly and
in sequence shown (Figure 2-42).
d. Final-tighten bolts an additional 90¡ (1/4-turn).
6. Install pushrods. Verify that they are in same sequence as
when removed. Also be sure heat treated (copper color)
end is toward rocker arm.
Figure 2-42: Cylinder Head Bolt Tightening
Sequence
7. Index crankshaft and pistons for rocker arm and shaft
installation as follows:
a. Position breaker bar and socket on crankshaft damper
bolt. Do not use starter motor to rotate crankshaft. Use
socket and wrench on damper bolt only.
b. Rotate crankshaft counterclockwise and align mark
on torsional damper with ÒOÓ (TDC) mark on front
cover timing tab.
c. Index crankshaft by rotating it counterclockwise an
additional 3-1/2 inches (89 mm). At this point, mark
on damper will be roughly aligned with first lower
water pump bolt (Figure 2-43).
8. Install rocker arm and shaft assemblies. Be sure pushrods
are properly seated in lifter and rocker arms. Do this
before tightening shaft retainer bolts. Install shaft retainers
and bolts. Tighten bolts evenly to 41 lb-ft (56 N¥m)
torque.
CAUTION: Stop tightening the shaft bolts if they become hard
to turn before fully seated.
WATER PUMP
FIRST LOWER
BOLT
3 1/2 IN.
(89 MM)
Figure 2-43: Crankshaft Indexing Position
9. Clean cylinder head and rocker cover sealing surfaces
thoroughly. Then finish-clean with brake or contact
cleaner and shop towels to remove cleaning residue. This
is necessary to ensure proper adhesion of sealer.
10. Apply sealer to rocker arm cover (Figure 2-44). Make
sealer bead 3/16 inch wide by 1/16 inch thick. Use RTV-
type silicone, adhesive-sealer such as Loctite 592, or
Permatex High Temp, Ultra Copper, or Ultra Blue. Allow
sealer to cure slightly (skin over) before installing cover.
Figure 2-44: Applying Sealer to Rocker Arm Cover
11. Align and install rocker cover. Tighten cover bolts to 16
lb-ft (22 N¥m) torque.
O (TDC) MARK
ON TIMING TAB
¨