Camshaft Inspection and Measurement. Cadillac Concours 1996

For 1990-2009 cars

#### Tools Required

J 7872 Magnetic Base Dial Indicator Set

1. 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

2. If any of the above conditions exist on the camshaft, replace the camshaft.
3. If any of the above conditions exist on the camshaft bearings, replace the cylinder head.
4. 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.

5. Install the camshaft bearing cap in the cylinder head without the camshaft.
6. Measure the camshaft bearings using an inside micrometer.
7. 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.

8. 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).

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