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.
Fig 1: Inspecting Camshaft For Wear
Courtesy of GENERAL MOTORS CORP.
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
3. Measure the camshaft journal diameter.
   Fig 2: Measuring Camshaft Journal Diameter

   Courtesy of GENERAL MOTORS CORP.
   • 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.
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.