Camshaft and Bearings Cleaning and Inspection

Tools Required 

J 7872  Magnetic Base Dial Indicator Set. See Special Tools .

1. Clean the camshaft with cleaning solvent.
Fig 1: Inspecting Camshaft
Courtesy of GENERAL MOTORS CORP.
CAUTION: Refer to Cleaning Solvent Caution in Cautions and Notices.
2. Inspect the camshaft for the following conditions:
   • Scored camshaft bearing journals (1)
   • Damaged camshaft lobes (2)
   • Damaged camshaft sprocket locator pins (3)
   • Damaged threads (4)
   • Damage to the camshaft reluctor tooth (5)
Fig 2: Measure Camshaft Journals With Micrometer
Courtesy of GENERAL MOTORS CORP.
3. Measure the camshaft journals using a micrometer.

   If the camshaft journals are not within specifications, replace the camshaft.

Fig 3: Measuring Camshaft Runout
Courtesy of GENERAL MOTORS CORP.
4. Measure the camshaft runout using the J 7872  . See Special Tools .
   1. Mount the camshaft in V-blocks between the centers.
   2. Use the J 7872  in order to measure the intermediate camshaft journal. See Special Tools .
5. Measure the camshaft lobe lift using the J 7872  . See Special Tools .
   1. Lubricate the camshaft using GM P/N 12345501 (Canadian P/N 992704) or the equivalent.
   2. Set the camshaft on V-blocks.
   3. Use the J 7872  in order to measure the lobe lift. See Special Tools .
6. If the runout or lobe lift is not within specifications, replace the camshaft.