Camshaft: Testing and Inspection

CAMSHAFT RUNOUT
1. Place the camshaft on V-blocks.
2. Using a dial indicator, measure the circle runout at the center journal.
Maximum circle runout: 0.080 mm (0.0031 inch)
3. If the circle runout is greater than maximum, replace the camshaft.





CAM LOBES
1. Using a micrometer, measure the cam lobe height.
Standard cam lobe height:
Intake: 42.210-42.310 mm (1.6618-1.6657 inch)
Exhaust: 41.960-42.060 mm (1.6520-1.6559 inch)
Minimum cam lobe height:
Intake: 42.060 mm (1.6559 inch)
Exhaust: 41.810 mm (1.6461 inch)
2. If the cam lobe height is less than minimum, replace the camshaft.





CAMSHAFT JOURNAL DIAMETER
1. Using a micrometer, measure the journal diameter.
Journal diameter:
Exhaust camshaft thrust bearing journal, (A) in illustration: 23.959-23.975 mm (0.9433-0.9439 inch)
All other camshaft journals: 26.954-26.970 mm (1.0612-1.0618 inch)
2. If the journal diameter is not as specified, check the oil clearance.





CAMSHAFT GEAR SPRING
1. Using vernier calipers, measure the free distance between the spring ends.
Free distance: 18.200-18.800 mm (0.7120-0.7400 inch)
2. If the free distance is not as specified, replace the gear spring.





CAMSHAFT BEARING SURFACE
Check that bearings for flaking and scoring. If the bearings are damaged, replace the bearing caps and cylinder head as a set.





CAMSHAFT JOURNAL OIL CLEARANCE
1. Clean the bearing caps and camshaft journals.


2. Place the camshafts on the cylinder head as outlined below.

NOTE: Do not turn the camshaft.





3. Lay a strip of Plastigage across each of the camshaft journals.
4. Install the bearing caps. Refer to Installation.





5. Measure the Plastigage at its widest point.
Standard oil clearance:
Exhaust camshaft thrust journal: 0.025-0.061 mm (0.0010-0.0024 inch)
All other journals: 0.030-0.067 mm (0.0012-0.0026 inch)
Maximum oil clearance: 0.100 mm (0.0039 inch)
6. If the oil clearance is greater than maximum, replace the camshaft and /or the bearing caps and cylinder head set as required.
7. Completely remove the Plastigage.
8. Remove the camshafts.

CAMSHAFT THRUST CLEARANCE
1. Install the camshafts.





2. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
Standard thrust clearance: 0.040-0.090 mm (0.0016-0.0035 inch)
Maximum thrust clearance: 0.120 mm (0.0047 inch)
3. If the thrust clearance is greater than maximum, replace the camshaft and/or the bearing caps and cylinder head set as required.
4. Remove the camshafts.





CAMSHAFT GEAR BACKLASH
1. Install the camshafts without installing the exhaust cam sub-gear as described under Camshaft Journal Oil Clearance above.
2. Using a dial indicator, measure the backlash.
Standard backlash: 0.020-0.200 mm (0.0008-0.0079 inch)
Maximum backlash: 0.300 mm (0.0188 inch)
3. If the backlash is greater then maximum, replace the camshafts.
4. Remove the camshafts as described under Camshaft Journal Oil Clearance above.