32. Cylinder Head Cleaning and Inspection
Cylinder Head Cleaning and Inspection
1. Inspect cylinder head for warpage.
2. Using a precision straight edge and a feeler gauge, measure the surface contacting the cylinder block and the manifolds for warpage.
If the warpage is greater than the maximum, replace the cylinder head.
3. Using a dye penetrant, check the intake ports, exhaust ports and cylinder surface for cracks. If cracked, replace the cylinder head.
4. Install the camshafts.
5. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
If the thrust clearance is greater than the maximum, replace the cylinder head. If the thrust surface is damaged, replace the camshaft.
6. Inspect camshaft oil clearance.
7. Clean the bearing caps and camshaft journals.
8. Place the camshafts on the cylinder head.
9. Lay a strip of Plastigage across each of the camshaft journals.
Note: Do not turn the camshaft.
10. Install the bearing caps.
11. Remove the bearing caps.
Note: Completely remove the Plastigage after the inspection.
12. Measure the Plastigage at its widest point.
13. If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the cylinder head.
14. If the oil clearance on the camshaft No. 1 journal is greater than the maximum, choose a new bearing and install it.
15. Check the number mark shown in the illustration.
35.971 to 35.985 mm (1.4162 to 1.4167 in)
16. Inspect inner compression spring.
17. Using vernier calipers, measure the free length of the valve spring.
47.43 mm (1.867 in)
If the free length is not as specified, replace the valve spring.
18. Using a steel set square, measure the deviation of the valve spring.
1.6 mm (0.063 in)
If the deviation is greater than the maximum, replace the valve spring.
19. Inspect intake valve
20. Using a gasket scraper, scrape off any carbon on the valve head.
21. Using vernier calipers, measure the overall length of the valve.
* Standard overall length: 101.71 mm (4.0043 in)
* Minimum overall length: 101.21 mm (3.9846 in)
If the overall length is less than the minimum, replace the valve.
22. Using a micrometer, measure the diameter of the valve stem.
5.470 to 5.485 mm (0.2154 to 0.2159 in)
If the valve stem is not as specified, check the oil clearance.
23. Using vernier calipers, measure the valve head margin thickness.
* Standard margin thickness: 1.05 to 1.45 mm (0.0413 to 0.0571 in)
* Minimum margin thickness: 0.50 mm (0.0197 in)
If the margin thickness is less than the minimum, replace the valve.
24. Using a gasket scraper, scrape off any carbon on the valve head.
25. Using vernier calipers, measure the overall length of the valve.
* Standard overall length: 101.15 mm (3.9823 in)
* Minimum overall length: 100.70 mm (3.9646 in)
If the overall length is less than the minimum, replace the valve.
26. Using a micrometer, measure the diameter of the valve stem.
5.465 to 5.480 mm (0.2152 to 0.2157 in)
If the valve stem is not as specified, check the oil clearance.
27. Using vernier calipers, measure the valve head margin thickness (a).
* Standard margin thickness: 1.20 to 1.60 mm (0.0472 to 0.0630 in)
* Minimum margin thickness: 0.50 mm (0.0197 in)
If the margin thickness is less than the minimum, replace the valve.
28. Using a caliper gauge, measure the inside diameter of the guide bush.
5.510 to 5.530 mm (0.2169 to 0.2177 in)
29. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
* Standard oil clearance: 0.025 to 0.060 mm (0.0010 to 0.0024 in)
* Maximum oil clearance: 0.090 mm (0.0035 in)
If the clearance is greater than the maximum, replace the valve and guide bush.
30. Using a caliper gauge, measure the inside diameter of the guide bush.
5.510 to 5.530 mm (0.2169 to 0.2177 in)
31. Subtract the valve stem diameter measurement from the guide bushing inside diameter measurement.
* Standard oil clearance: 0.030 to 0.065 mm (0.0012 to 0.0026 in)
* Maximum oil clearance: 0.095 mm (0.0037 in)
If the clearance is greater than the maximum, replace the valve and guide bush.
32. Using a micrometer, measure the lifter diameter.
30.966 to 30.976 mm (1.2191 to 1.2195 in)
33. Using a caliper gauge, measure the lifter bore diameter of the cylinder head.
31.009 to 31.025 mm (1.2208 to 1.2215 in)
34. Subtract the lifter diameter measurement from the lifter bore diameter measurement.
* Standard oil clearance: 0.033 to 0.059 mm (0.0013 to 0.0023 in)
* Maximum oil clearance: 0.079 mm (0.003 in)
If the oil clearance is greater than the maximum, replace the lifter. If necessary, replace the cylinder head.
35. Inspect cylinder head set bolt.
36. Using vernier calipers, measure the length of the head bolts from the seat to the end.
* Standard bolt length: 141.3 to 142.7 mm (5.563 to 5.618 in)
* Maximum bolt length: 144.2 mm (5.677 in)
If the bolt length is greater than the maximum, replace the cylinder head set bolt.
