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Fig. 179: Measuring Camshaft Lobe Lift Using
Courtesy of GENERAL MOTORS CORP.
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.
1. Measure camshaft lobe lift using J 8520 .
1. Remove the valve rocker arms and bolts
2. Install the dial indicator mounting stud into the valve rocker arm bolt hole.
3. Assemble the components of the J 8520 and position onto the stud.
4. Position the shaft of the dial indicator onto the end of the pushrod.
5. Rotate the face of the dial indicator to zero.
6. Slowly rotate the crankshaft clockwise until the dial indicator obtains its highest and lowest
readings.
7. Compare the total lift shown to specifications.
The proper lobe lift for the LS1 intake lobes is 6.96 mm (0.274 in).
The proper lobe lift for the LS1 exhaust lobes is 7.13 mm (0.281 in).
The proper lobe lift for the LS6 intake lobes is 8.24 mm (0.324 in).
The proper lobe lift for the LS6 exhaust lobes is 8.19 mm (0.322 in).
8. Remove the tool.
2. Compare measurements to specifications.
If the readings are not within specifications, remove the camshaft. Inspect and/or replace components as
required.
CAMSHAFT BEARING INSTALLATION
Tools Required
J 33049 Camshaft Bearing Service Set
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