Envoy 4WD V8-5.3L VIN P (2004)
13. Measure the camshaft runout.
13.1.
Mount the camshaft in wooden V blocks or between centers on a fixture.
13.2.
Check the runout of the intermediate camshaft bearing journals using the J 7872.
13.3.
If camshaft runout exceeds 0.05 mm (0.002 inch), the camshaft is bent and should be replaced.
Measuring Camshaft Lobe Lift
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.
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.
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 lift shown to specifications:
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The proper lobe lift for 5.3L intake lobes is 6.82 mm (0.268 inch).
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The proper lobe lift for 5.3L exhaust lobes is 6.96 mm (0.274 inch).
