Tools Required
J 7872 Magnetic Base
Dial Indicator Set
- Inspect the camshaft journals,
lobes and bearings for the following conditions:
• | Excessive scoring or pitting |
• | Discoloration from overheating |
• | Deformation from excessive wear, especially the camshaft lobes |
- If any of the above conditions exist on the camshaft, replace
the camshaft.
- If any of the above conditions exist on the camshaft bearings,
replace the cylinder head.
- Measure the camshaft journals
for diameter and out-of-round using an outside micrometer.
• | If the diameter is smaller than 26.948 mm (1.061 in),
replace the camshaft. |
• | If the out-of-round exceeds 0.022 mm (0.0009 in),
replace the camshaft. |
- Install the camshaft bearing cap in the cylinder head without
the camshaft.
- Measure the camshaft bearings using an inside micrometer.
- Subtract the camshaft journal diameter from the bearing diameter.
This will provide the running clearance.
If the running clearance exceeds 0.041-0.085 mm (0.0016-0.0033 in)
and the camshaft journals are within specification, replace the cylinder head.
- Measure the camshaft lobes
for wear using the following procedure:
8.1. | With the camshaft supported in V-blocks, set up the J 7872
with the indicator tip on the base circle
of the camshaft lobe. |
8.2. | Rotate the camshaft until the indicator tip is at the highest
point on the lobe. This reading is the lift(1) of the camshaft lobe. |
8.3. | The specifications for lift are as follows: |
RPO LD8 - VIN Y
• | Intake camshaft lift: 8.6 mm (0.339 in). |
• | Exhaust camshaft lift: 8.6 mm (0.339 in). |
RPO L37 - VIN 9
• | Intake camshaft: 9.4 mm (0.370 in). |
• | Exhaust camshaft: 8.6 mm (0.339 in). |
- If the indicated measurement is significantly lower than these
specifications, replace the camshaft or engine performance will be reduced.