Cylinder Heads

Cleaning

With valves installed to protect the seats, remove deposits from the combustion chambers and valve heads with a scraper and a wire brush. Be careful not to damage cylinder head gasket surface. After valves are removed, clean valve guide bores with a valve guide cleaning tool. Use cleaning solvent to remove dirt, grease and other deposits; clean all tapped bolt holes; make sure valve seats, gasket surfaces and oil return passages are clean. Clean all valve assembly components using a suitable solvent and dry thoroughly.

Inspection

1. Examine cylinder head (6049) for cracks in combustion chambers, intake and exhaust valve ports, and around intake valve seats. Inspect exhaust valve seats for burned or cracked condition. Inspect gasket and sealing surfaces for scratches or mars which may cause leakage after assembly.

   

2. NOTE: Cylinder heads cannot be resurfaced. Replace cylinder head if it is cracked or warped.

   To determine if cylinder head has previously been resurfaced, use an outside micrometer and measure cylinder head thickness at four locations. If minimum specification is not met, replace the cylinder head. Refer to Specifications at the end of this section.

   

3. Measure valve seat width. Reface valve seat(s) if width is not within specifications. Refer to Specifications at the end of this section.

   

Cylinder Head Flatness

Using a straightedge and a 0.15mm (0.006-inch) feeler gauge, check cylinder head gasket surface for warpage horizontally, diagonally and transversely. Check cylinder block deck for flatness in the same manner. Refer to Specifications at the end of this section.