Hummer H1 (2006+). Manual - part 31

2-30

Engine

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VALVE ROCKER ARM SHAFT AND PUSH ROD REPLACEMENT

Removal

1.

Remove the lower valve rocker arm covers.

2.

Loosen the valve clearance lock nuts on each rocker arm.

3.

Loosen the valve clearance adjusting screw on each rocker arm in order to relieve tension on the valve train.

4.

Remove the rocker arm shaft assembly bolts in the sequence shown (Figure  2-23). Leave the bolts in the rocker arm shaft
brackets.

Figure 2-23:   Rocker Arm Shaft Removal 

S

equence

5.

Remove the rocker arm shaft assembly from the cylinder head.

6.

Remove the valve bridge pins (Figure  2-24).

7.

Remove the valve bridges (Figure  2-24).

8.

Remove the pushrods (Figure  2-24).

2

5

3

4

1

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 Engine  2-31

5745804

Figure 2-24:   Push Rods, Valve Bridge and Valve Bridge Pins

Installation

1.

Lubricate the top of the valves, the valve bridge stem, the valve lifter bridge and the valve spring caps with clean engine oil.

2.

Install the valve bridge.

3.

Install the valve bridge pins.

4.

Lubricate the valve lifter end of the pushrod with clean engine oil.

5.

Install the pushrods.

NOTE: The pushrods must be correctly seated in the valve lifter and valve rocker arms before the rocker arm shaft assembly is
torqued into place. Improper seating of the pushrods can cause damage to the pushrods or the valve rocker arm shaft assembly
components.

6.

Install the rocker arm shaft assembly.

7.

Torque the rocker arm shaft bolts in the sequence shown (Figure  2-25) to 30þlb-ft. (41þN·m).

8.

Adjust the valve clearance (Refer to section 2).

9.

Install the lower valve rocker arm covers.

PUSH ROD

VALVE BRIDGE

PIN

VALVE BRIDGE

2-32

Engine

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Figure 2-25:   Rocker Arm Shaft Torque 

S

equence

4

3

1

2

5

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 Engine  2-33

5745804

VALVE LASH ADJUSTMENT

1.

Rotate the crankshaft to bring the number 1 cylinder at the top dead center of the compression stroke (Figure  2-26). The num-
ber 1 cylinder is the front cylinder on the right bank. The mark on the crankshaft balancer should be aligned with the mark on 
the engine.

Figure 2-26:   Top Dead Center Mark

2.

Refer to  Figure 2-27 to determine which valves that can be adjusted when the engine is at Top Dead Center.

ALIGNMENT 

MARKS