Special Tools

J 7872 Magnetic Base Dial Indicator

For equivalent regional tools, refer to Special Tools.

1. Clean the camshaft in solvent.

Warning: Refer to Safety Glasses Warning in the Preface section.

2. Dry the camshaft with compressed air.

1. Inspect the camshaft oil feed holes (1) to the camshaft position actuator for dirt, debris or blockage.
2. Inspect the threaded hole (2) for damage.
3. Inspect the camshaft position actuator locating notch (3) for damage or wear.
4. Inspect the camshaft sealing grooves (4) for damage.
5. Inspect the camshaft thrust surface (5) for damage.
6. Inspect the camshaft lobes (6) and journals (7) for the following conditions:

•	Excessive scoring or pitting

•	Discoloration from overheating

•	Deformation from excessive wear, especially the camshaft lobes

7. If any of the above conditions exist on the camshaft, replace the camshaft.

1. With the camshaft in a suitable fixture, measure the camshaft for wear.



2. Measure the camshaft journals for diameter and out-of-round using an outside micrometer. Refer to Engine Mechanical Specifications.

•	If the diameter is smaller than specifications, replace the camshaft.

•	If the out-of-round exceeds specifications, replace the camshaft.




3. Measure the camshaft runout using the J 7872 indicator . Refer to Engine Mechanical Specifications.



4. Measure the camshaft thrust width for wear using a depth micrometer. Refer to Engine Mechanical Specifications.



5. Measure the camshaft thrust wall surface for runout using J 7872 indicator . Refer to Engine Mechanical Specifications.
6. If the camshaft is damaged or worn beyond specifications, replace the camshaft. No machining of the camshaft is allowed.



7. Measure the camshaft lobes for wear using the J 7872 indicator .



8. Place the J 7872 indicator with the indicator tip on the base circle (1) of the camshaft lobe.

8.1.	Place the J 7872 indicator at zero.

8.2.	Rotate the camshaft until the indicator tip is at the highest point (3) on the lobe. This reading is the lift of the camshaft lobe. Refer to Engine Mechanical Specifications.

8.3.	If the indicated measurement is significantly lower than these specifications, replace the camshaft or engine performance will be reduced.