Chevrolet Silverado / GMC Sierra. Service manual — part 371

Fig. 484: Valve Stem Keys, Valve Spring Cap & Valve Spring
Courtesy of GENERAL MOTORS CORP.

1. Clean the cylinder head valve spring shim area.

2. Install the valves (228) into the proper port. Refer to Separating Parts.

IMPORTANT: When using the valves and related components again, install

the parts to their original location.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

3. Install the valve stem oil seal (222).

4. Install the valve spring (223).

5. Install the valve spring cap (224).

Fig. 485: Compressing Valve Spring Using
Courtesy of GENERAL MOTORS CORP.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

6. Using the J 8062 , compress the valve spring. See Special Tools.

7. Install the valve stem keys.

1. Use grease in order to hold the keys in place and remove the J 8062 . See Special

Tools.

2. Ensure the keys seat properly in the groove of the valve stem.

3. Tap the end of the valve stem with a plastic face hammer to seat the keys, if necessary.

Fig. 486: Measuring Valve Spring Installed Height
Courtesy of GENERAL MOTORS CORP.

8. Using a ruler, measure the valve spring installed height.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

Measure from the base of the valve spring to the top of the valve spring.

Specification:

If the installed height exceeds 46.25 mm (1.82 in), install a valve spring shim of
approximately 0.5 mm (0.02 in) thick.

Do not shim the valve spring to obtain less than the specified height.

Do not assemble the components without a spring shim on the cylinder head.

9. Install the remaining valves, springs, and other components.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2