Cylinder Head Clean and Inspect

CYLINDER HEAD RESURFACING





1. Inspect the camshaft bearings and the journals for evidence of scoring.
2. If the camshaft bearing journals appear to be scored or damaged, you must replace the cylinder head. DO NOT machine the camshaft bearing journals.
3. Inspect the valve seats for cracking or pitting.
4. Inspect the cylinder head gasket for signs of coolant leakage.





5. Measure the cylinder head flatness using the following procedure:
5.1. Clean any remaining head gasket material from the cylinder head face.
5.2. Place a straight-edge diagonally across the cylinder head face surface.
5.3. Measure the clearance between the straight-edge and the cylinder head using a feeler gage at four points along the straight-edge.
5.4. If warpage is less than 0.05 mm (0.002 inch), the cylinder head surface does not require resurfacing.
5.5. If the warpage is between 0.05 mm and 0.2 mm (0.002 inch and 0.008 inch), you must resurface the head.





6. If resurfacing is required, the dimension between the combustion chamber gauge pad and the deck surface must be at least 10.5 mm.

VALVE GUIDE INSPECTION
1. Check the valve stem to guide clearance using a hole gage and an outside micrometer.
2. Measure the valve guide inside diameter with a hole gage, crossways to the engine, at both the top and 10 mm (0.39 inch) up from the bottom of the guide, measuring gage each time with micrometer. A standard size valve guide is 5.979 mm (0.235 inch).
3. Measure the valve stem diameter with the micrometer and subtract from the greater of two guide measurements to obtain the maximum clearance.
4. If the clearance for the intake valve is greater than 0.11 mm (0.0045 inch) and a new standard diameter valve stem will not bring the clearance within specifications, the cylinder head must be replaced.
5. If the clearance for the exhaust valve is greater than 0.12 mm (0.0005 inch) and a new standard diameter valve stem will not bring the clearance within specifications, the cylinder head must be replaced.
6. Valve guide wear at the bottom 10 mm (0.39 inch) of the valve guide is not significant to normal operation.