Tools Required

J 8089 Carbon Removing Brush

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 heads on a buffing wheel.
2. Clean the following components in solvent

•	Valve stem keys (1)

•	Valve spring cap (2)

•	Valve spring (4)

•	Valve rotators (5)

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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 scuff the chamber or damage 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 gauge.

•	A cylinder head block deck with warpage in excess of 0.076 mm (0.003 in) within a 152.4 mm (6.0 in) area must be repaired or replaced.

•	A cylinder head exhaust manifold deck with an overall warpage in excess of 0.152 mm (0.006 in) must be repaired or replaced.

•	A cylinder head intake manifold deck with warpage in excess of 0.10 mm (0.004 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)

•	Wear, 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.

Tools Required

J 9666 Valve Spring Tester

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



2. Use the J 9666 in order to measure the valve spring tension. 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 low valve spring tension is found, use a shim to increase tension.
4. Recheck the valve spring tension, a valve spring that does not meet specification must be replaced.

Tools Required

J 8001 Dial Indicator Set

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.

•	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.

•	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.

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

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

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2. A 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.