45. Cylinder Head Clean and Inspect
Cylinder Head Cleaning and InspectionTools Required
* J8089 Carbon Removal Brush
* J9666 Valve Spring Tester
* J8001 Dial Indicator Set
Cleaning Procedure
Caution: Refer to Safety Glasses in Service and Precautions.
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: Refer to Safety Glasses in Service and Precautions.
3. Dry the components with compressed air.
Important: Be careful not to damage the chamber or the valve seat.
4. Use the J8089 in order to clean the carbon from the combustion chambers.
Visual Inspection Procedure
Inspect the cylinder head for the following conditions:
* Damaged gasket surfaces
* Damage to threaded bolt holes
* Burnt or eroded areas in the combustion chamber
* Cracks in the exhaust ports and combustion chambers
* External cracks in the water chamber
* Restrictions in the intake or exhaust passages
* Restrictions in the cooling system passages
Flatness Measurement Procedure
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 inch) within a 150.0 mm (6.0 inch) area must be repaired or replaced
- A cylinder head exhaust manifold deck with an overall warpage in excess of 0.102 mm (0.004 inch) must be repaired or replaced.
- A cylinder head intake manifold deck with warpage in excess of 0 080 mm (0.003 inch) must be repaired or replaced.
2. A cylinder head block deck can be resurfaced up to 0.305 mm (0.012 inch) 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.
Valve Inspection Procedure
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 stern 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.
Valve Spring Inspection and Measurement
1. Inspect the valve springs for broken coils or coil ends.
2. Use the J9666 in order to measure the valve spring force.
Important: Add a maximum of one shim up to 0.726 mm (0.030 inch) 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.
Valve Guide Measurement Procedure
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 J8001 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 inch) 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.
2. Valve guide (2) with excessive clearance must be repaired.
3. Replace the cylinder head if the valve guide cannot be repaired or reamed to accept an oversize valve stem.