Tools Required

1. Use the J 8089 to clean the carbon from the combustion chambers and from the valves.
2. Clean the valve guides.
3. Use a buffing wheel to clean the valve stems and valve heads.
4. Clean the cylinder head.
5. Clean the engine block gasket surfaces.
6. Clean the bolt hole threads in the cylinder head and in the engine block.
7. Cracks in the cylinder head usually occur between the exhaust valves or between the exhaust valve and the spark plug hole. Inspect for the following in the cylinder head:

•	Inspect for cracks in the exhaust ports.

•	Inspect for cracks in the combustion chambers.

•	Inspect for external cracks to the water chamber.




8. Inspect the valves for the following:

•	Inspect for burned heads (1).

•	Inspect for cracked faces (2).

•	Inspect for damaged stems (3, 4).

9. Inspect the valve seats for cracks.
10. Inspect the valve seats for looseness.



11. Perform the following steps to inspect the valve springs for squareness:

•	Place the valve spring on a level surface next to a square.

•	Rotate the valve spring.

•	Replace the valve spring if the valve spring is more than 1.58 mm (0.062 in) out of square.




12. Use the J 9666 to inspect the valve spring tension.
13. Replace the spring if the spring length is less than 34 mm (1.338 in) when subjected to a compressive force of 252 N·m (56.6 lb).



14. Perform the following steps to inspect the valve stem-to-valve guide clearance:

14.1.

Clamp the J 8001 on the exhaust port side of the cylinder head.

14.2.

Locate the indicator so that the movement of the valve stem from side to side (crosswise to cylinder head) will cause a direct movement of the dial indicator stem.

14.3.

Measure the valve head with the valve protruding 10 mm (0.39 in) from the seat.

14.4.

Drop the valve head about 10 mm (0.393 in) off the valve seat.

14.5.

Use light pressure to move the stem of the valve from side to side to obtain a clearance reading.

14.6.

The intake valve clearance should be 0.030 - 0.057 mm (0.0011 - 0.0022 in).

14.7.

The exhaust valve clearance should be 0.040 - 0.067 mm (0.0015 - 0.0026 in).

15. If the valve clearance is out of specifications, measure the valve stem in three locations shown in the illustration.
16. Compare the lowest measurement to the specifications below:

•	Intake valve stem: 5.955 - 5.970 mm (0.2344 - 0.2350 in).

•	Exhaust valve stem: 5.945 - 5.960 mm (0.2340 - 0.2346 in).

17. If the valve stem diameter is out of specification, replace the valve.
18. If the valve stem is within the specifications, the valve guide is worn.

•	The valve guide can be reamed oversize.

•	If the valve guide is reamed oversize, an oversize valve must be installed.