Hummer H2. Manual — part 1858

Fig. 595: Determining Cylinder Bore Out-Of-Round Using J 8087
Courtesy of GENERAL MOTORS CORP.

5. Using the J 8087 , measure the cylinder bore inside diameter (ID). Measure at a point 64 mm (2.5 in)

from the top of the cylinder. See Special Tools and Equipment .

6. Record the cylinder bore ID.

7. Subtract the piston OD from the cylinder bore ID to determine the piston-to-bore clearance. Refer to

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

Engine Mechanical Specifications .

8. If the proper clearance cannot be obtained, select another piston, pin, and connecting rod assembly and

again measure the clearances. If the proper fit cannot be obtained, the cylinder bore may require honing
for an oversize piston.

Piston, Pin, and Connecting Rod Installation

Fig. 596: Piston & Connecting Rod Components
Courtesy of GENERAL MOTORS CORP.

1. Lightly lubricate the following components with clean engine oil:

z

Piston (1)

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

z

Piston rings

z

Cylinder bore

z

Bearings (3) and bearing surfaces

2. Position the oil control ring end gaps a minimum of 25 mm (1.0 in) from each other.

3. Position the compression ring end gaps 180 degrees opposite each other.

Fig. 597: View Of J 41556 & Connecting Rod
Courtesy of GENERAL MOTORS CORP.

4. Install the J 41556 to the connecting rod. See Special Tools and Equipment .

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2

Fig. 598: Installing Piston Using J 8037
Courtesy of GENERAL MOTORS CORP.

5. Install the J 8037 onto the piston and compress the piston rings. See Special Tools and Equipment .

6. Install the piston, pin, and connecting rod assembly into the cylinder bore. Hold the piston ring

compressor firmly against the engine block. Using a wooden hammer handle, lightly tap the top of the
piston until all the piston rings have entered the cylinder bore.

IMPORTANT: The piston alignment mark MUST face the front of the engine block.

2004 Hummer H2

2004 ENGINE Engine Mechanical - 4.8L, 5.3L, and 6.0L - Hummer H2