Special Tools

J 7872 Magnetic Base Dial Indicator

For equivalent regional tools, refer to Special Tools.

1. Clean the camshaft with cleaning solvent.




Warning: Bodily injury may occur if the cleaning solvent is inhaled or exposed to the skin.

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)




3. Measure the camshaft journals using a micrometer.

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




4. Measure the camshaft runout using the J 7872 indicator .

4.1.	Mount the camshaft in V-blocks between the centers.

4.2.	Use the J 7872 indicator in order to measure the intermediate camshaft journal.

5. Measure the camshaft lobe lift using the J 7872 indicator .

5.1.	Lubricate the camshaft using GM P/N United States 12345501, GM P/N Canada 992704 or the equivalent.

5.2.	Set the camshaft on V-blocks.

5.3.	Use the J 7872 indicator in order to measure the lobe lift.

6. If the runout or lobe lift is not within specifications, replace the camshaft.