Chevrolet Silverado / GMC Sierra. Service manual — part 361

Fig. 452: Measuring Camshaft Runout
Courtesy of GENERAL MOTORS CORP.

13. Measure the camshaft runout.

1. Mount the camshaft in wooden V-blocks or between centers on a fixture.

2. Using the J 7872 , measure the runout of the intermediate camshaft bearing journals.

3. If camshaft runout exceeds 0.05 mm (0.002 in), the camshaft is bent and should be

replaced.

Measuring Camshaft Lobe Lift

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

Fig. 453: Measuring Camshaft Lobe Lift
Courtesy of GENERAL MOTORS CORP.

1. Using the J 8520 , measure camshaft lobe lift. See Special Tools.

2. Remove the valve rocker arms and bolts.

3. Install the dial indicator mounting stud into the valve rocker arm bolt hole.

4. Assemble the components of the J 8520 and position onto the stud. See Special Tools.

5. Position the shaft of the dial indicator onto the end of the pushrod.

6. Rotate the face of the dial indicator to zero.

7. Slowly rotate the crankshaft clockwise, until the dial indicator obtains its highest and lowest

readings.

8. Compare the total to specifications. Refer to Engine Mechanical Specifications.

CAMSHAFT BEARING INSTALLATION

Tools Required

J 33049 Camshaft Bearing Service Set. See Special Tools.

IMPORTANT: Measuring camshaft lobe lift is a procedure used to

determine if the camshaft lobes have worn. This test is to be
performed prior to engine disassembly and with the camshaft
and valve train components installed in the engine.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2

Fig. 454: Identifying Engine Block Camshaft Bearing Bores
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: The engine block camshaft bearing bores are machined for 3

different outside diameter (OD) size bearings. Position 1 and
5 are the largest diameter bores. Position 3 is the smallest
diameter bore. Position 2 and 4 are the intermediate size
bores. The inside diameter (ID) for all camshaft bearings is
the same size.

2008 Hummer H2

2008 ENGINE Engine Mechanical - 6.2L - H2