31. Camshafts Cleaning and Inspection

Camshafts Cleaning and Inspection

Tools Required

* J 26900-2 Outside Micrometer
* J 8001 Dial Indicator Set
* J 26900-13 Magnetic Indicator Base




1. Inspect the camshaft journals and lobes for wear or scoring (1, 2).
2. Wash the cylinder head in solvent.
3. Inspect the cylinder head for cracks or other signs of damage.
4. Inspect the camshaft bearing caps for wear, cracks and scoring.
5. Inspect the camshaft bearing journals in the cylinder head for wear, cracks and scoring.
6. If excessive wear or scoring is present, or if the cylinder head is cracked, replace the cylinder head (with bearing caps).




7. Measure the camshaft lobe height using the J 26900-2. Replace the camshaft if any lobe is below the minimum.

40.607-40.707 mm (1.5958-1.5997 in)

38.769-38.869 mm (1.52362-1.52755 in)

40.45 mm (1.5925 in)

38.61 mm (1.5201 in)

40.019-40.119 mm (1.57275-1.57668 in)

38.863-38.963 mm (1.52732-1.53125 in)

39.86 mm (1.5693 in)

38.71 mm (1.5240 in)




8. Place the camshaft (1) onto V-blocks. Measure the camshaft runout using the J 8001 with the J 26900-13. Replace the camshaft if the runout exceeds specifications.

0.03 mm (0.0012 in)

9. Clean the journals of the camshaft and the cylinder head.
10. Do not install the valve lifters.




11. Install the camshafts.

Important: Do not turn the camshafts while the gaging plastic is installed.

12. Place a piece of gaging plastic across the full width of each camshaft journal.

Important: Cylinder head and camshaft damage may result if the bearing caps are incorrectly installed. The oil clearance measurement will also be incorrect.

13. Install the camshaft bearing caps in their original locations.

Notice: Refer to Fastener Notice.

14. Use 3 progressive steps to tighten the camshaft bearing cap bolts in sequence.

Tighten the bolts to 18.5 N.m (14 lb ft).

15. Remove the camshaft bearing caps.
16. Measure the gaging plastic at its widest point.

0.035-0.076 mm (0.0014-0.0030 in)

0.035-0.072 mm (0.0014-0.0028 in)

0.10 mm (0.0039 in)

17. If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the cylinder head with caps as a set.
18. Install the camshafts.
19. Using the J 8001, measure the thrust clearance while moving the camshaft back and forth.

0.04-0.14 mm (0.0016-0.0055 in)

0.15 mm (0.0059 in)

20. If the thrust clearance is greater than maximum, replace the camshaft. If necessary, replace the bearing caps and cylinder head as a set.