Tools Required

Caution: Wear safety glasses in order to avoid eye damage.

Important: Mark, sort, or organize components for return to their original locations.

1. Clean the valve stems and heads on a buffing wheel.
2. Clean the following components in solvent:

•	Valve stem keys (1)

•	Valve spring cap (2)

•	Valve spring (3)

•	Valve Rotators (5)

•

Valve (6)

•	Cylinder head

Caution: Wear safety glasses in order to avoid eye damage.

3. Dry the components with compressed air.




Important: Be careful not to damage the chamber or the valve seat.

4. Use the J 8089 in order to clean the carbon from the combustion chambers.

Inspect the cylinder head for the following conditions:

1. Measure the cylinder head for warpage with a straight edge and feeler gage.

•	A cylinder head block deck with warpage in excess of 0.050 mm (0.002 in) within a 150.0 mm (6.0 in) area must be repaired or replaced.

•	A cylinder head exhaust manifold deck with an overall warpage in excess of 0.102 mm (0.004 in) must be repaired or replaced.

•	A cylinder head intake manifold deck with warpage in excess of 0.080 mm (0.003 in) must be repaired or replaced.

2. A cylinder head block deck can be resurfaced up to 0.305 mm (0.012 in) maximum removal.

Important: Excessive cylinder head resurfacing will affect compression ratio and emission control.

3. A cylinder head that requires excessive resurfacing must be replaced.

1. Inspect the valves for the following conditions:

•	Burnt or damaged areas (1)

•	Undersized valve margin (2)

•	Bent stem (3)

•	Scoring or other damage to the stem (4)

•	Worn key groove (5)

•	Worn stem tip (6)




2. Inspect the valve contact surface for the following conditions:

•	Undersized margin (1)

•	Pitted surface (2)

•	Burnt or eroded areas (3)

•	Acceptable edge, margin (4)

Important: Minor imperfections of the valve may be corrected during reconditioning.

3. Valves with excessive damage must be replaced.

1. Inspect the valve springs for broken coils or coil ends.



2. Use the J 9666 in order to measure the valve spring force. Refer to Engine Mechanical Specifications .

Important: Add a maximum of one shim up to 0.726 mm (0.030 in) thick to increase tension.

3. If the valve spring tension is low, use a shim to increase tension.
4. Recheck the valve spring tension, a valve spring that does not meet specification must be replaced.

Important: Excessive valve stem-to-guide clearance may cause an excessive oil consumption and may also cause a valve to break. Insufficient clearance will result in noisy and sticky functioning of the valve and will disturb the engine assembly smoothness.

1. Measure the valve stem-to-guide clearance.

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

Important: The indicator stem must contract the side of the valve stem just above the valve guide.

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

1.3.	Drop the valve head about 1.6 mm (0.064 in) off the valve seat.

1.4.	Use light pressure when moving the valve stem from side to side in order to obtain a clearance reading. Refer to Engine Mechanical Specifications .




2. Valve guide (2) with excessive clearance must be repaired. Refer to Valve Guide Reaming, and Valve and Seat Grinding .
3. Replace the cylinder head if the valve guide cannot be repaired or reamed to accept an oversize valve stem.