Special Tools

J-7872:  Magnetic Base Dial Indicator

For equivalent regional tools, refer to Special Tools

Fig 1: View Of Camshaft & Actuator Filter
Courtesy of GENERAL MOTORS CORP.
1. Remove and discard the camshaft position actuator filter (1).
2. Clean the camshaft with cleaning solvent.
WARNING: Refer to Cleaning Solvent Warning .
3. Inspect the camshaft for the following conditions:
   • Scored camshaft bearing journals (5)
   • Damaged camshaft lobes (4)
   • Damaged camshaft position sensor reluctor area (3)
   • Damaged threads (2)
Fig 2: Measure Camshaft Journals With Micrometer
Courtesy of GENERAL MOTORS CORP.
4. Measure the camshaft journals using a micrometer.

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

Fig 3: Measuring Camshaft Runout Using J 7872
Courtesy of GENERAL MOTORS CORP.
5. Measure the camshaft runout using the J-7872:  Magnetic Base Dial Indicator.
   1. Mount the camshaft in V-blocks between the centers.
   2. Use the J-7872:  Indicator in order to measure the intermediate camshaft journal.
6. Measure the camshaft lobe lift using the J-7872:  Indicator.
   1. Lubricate the camshaft. Refer to Adhesives, Fluids, Lubricants, and Sealers for recommended lubricant.
   2. Set the camshaft on V-blocks.
   3. Use the J-7872:  Indicator in order to measure the lobe lift.
7. If the runout or lobe lift is not within specifications, replace the camshaft.
Fig 4: View Of Camshaft & Actuator Filter
Courtesy of GENERAL MOTORS CORP.
NOTE: Always install a NEW camshaft position actuator filter anytime the camshaft position actuator is removed or installed.
8. Install a NEW camshaft position actuator filter (1).