Hummer H3. Manual — part 325

Fig. 160: Installing Timing Chain & Sprockets
Courtesy of GENERAL MOTORS CORP.

1. Install the crankshaft sprocket to the crankshaft snout.

2. Install the intake camshaft sprocket into the timing chain.

IMPORTANT: Ensure the #1 piston is at TDC. The pin on the crankshaft for

the timing chain sprocket should be straight up.

IMPORTANT: Every 7th link of the timing chain is darkened to aid in

aligning the timing marks.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Aligning the dark link (1) of the timing chain with the timing mark on the intake camshaft
sprocket.

3. Feed the timing chain down through the opening in the cylinder head.

4. Install the timing chain on the crankshaft sprocket.

Aligning the dark link (2) of the timing chain with the timing mark on to the crankshaft
sprocket.

5. Install the intake camshaft sprocket onto the intake camshaft.

IMPORTANT: Ensure the alignment pin is properly engaged with the

camshaft

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 161: View Of Intake Camshaft Sprocket Washer & Bolt
Courtesy of GENERAL MOTORS CORP.

6. Install a NEW intake camshaft sprocket bolt.

Tighten: Tighten the bolt a first pass to 20 N.m (15 lb ft). Using the J 45059 rotate the bolt
a final pass an additional 100 degrees. See Special Tools.

NOTE:

Refer to Fastener Notice .

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

7. Ensure the camshaft actuator is fully advanced prior to installation. Refer to Camshaft

Position Actuator Diagnosis.

Fig. 162: View Of Exhaust Camshaft Actuator
Courtesy of GENERAL MOTORS CORP.

8. Install the exhaust camshaft actuator into the timing chain.

Aligning the dark link (1) of the timing chain with the timing mark (1) on the exhaust
camshaft position actuator sprocket.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3