Camshaft and Bearings Cleaning and Inspection

Tools Required 

J 7872  Dial Indicator Set

1. Clean the camshaft.
IMPORTANT: The camshaft bearings are not serviceable. If the camshaft bearings are damaged, the engine must be replaced.
2. Visually inspect the camshaft bearings in the engine block for the following conditions:
   • Scoring
   • Nicks
   • Damage caused by lack of lubrication
   • Misaligned oil feed holes
Fig 1: Camshaft Inspection Areas
Courtesy of GENERAL MOTORS CORP.
3. Measure the camshaft journal diameter.
   • The production value is 60.932-60.962 mm (2.3990-2.4001 in) and service limit is 60.920 mm (2.3984 in).
   • Replace the camshaft if the measured value is less than service limit.
Fig 2: Measuring Camshaft Journal Diameter
Courtesy of GENERAL MOTORS CORP.
4. Measure the camshaft lobe lift. The production value for intake is 7.273 mm (0.2863 in).
Fig 3: Measuring Camshaft Lobe Lift
Courtesy of GENERAL MOTORS CORP.
5. The production value for exhaust is 5.907 mm (0.2326 in).
6. Replace the camshaft if the measured value is less than the service limit.
7. Measure the camshaft runout.
   • Mount the camshaft on the V-blocks.
   • Use J 7872  to measure the camshaft runout.
   • The runout service limit is 0.05 mm (0.0020 in).
Fig 4: Measuring Camshaft Runout
Courtesy of GENERAL MOTORS CORP.
8. Replace the camshaft if the run-out is over the service limit.