Inspection

DESCRIPTION
Inspect Stems
Inspect each valve for damaged or bent stems, a rough or damaged face, and damaged or unevenly worn stem tips. Inspect the stem for grooves or scores.

Inspect the valve face and the edge of the valve head
Inspect the valve face and the edge of the valve head for pits, grooves or scores. Check the valve head for signs of burning or erosion, warpage and cracking. Minor pits, grooves and other abrasions may be removed. Discard severely damaged valves.

Inspect components
Inspect the valve spring (6513), valve spring retainers (6514), valve spring retainer keys (6518) and sleeves. Discard any damaged parts.

VALVE STEM DIAMETER





- Measure the valve stem diameters in three places. Replace the valves if stems are out of specification.
- The standard intake valve stems are 7.960-7.940 mm (0.3134-0.3126 inch).
- The standard exhaust valve stems are 7.948-7.928 mm (0.3129-0.3121 inch).

VALVE STEM CLEARANCE





- Measure the valve guide inner diameter.
- Subtract the valve stem diameter from the valve guide diameter and divide by two. This is the valve stem to guide clearance.
Valve Stem to Guide Clearance:
Intake 0.026-0.071 mm (0.001-0.0028 inch).
Exhaust 0.038-0.083 mm (0.0015-0.0033 inch).
- If the clearance is greater than specified, replace the valve or valve guide, or both, depending on the dimension that is causing the excess clearance.

VALVE STEM END REFINISHING
Remove all grooves or score marks from the end of the valve stem and chamfer it as necessary.

VALVE HEAD MARGIN THICKNESS
- Inspect the valve head margin thickness of each valve. If measurement is out of specification replace valve as the valve will run too hot in the engine.
Exhaust and Intake: 0.79 mm (1/32 inch).

VALVE FACE RUNOUT
If the valve face runout is excessive and/or it is necessary to remove pits and grooves, reface the valve to a true 44° angle. Remove only enough stock to correct the runout or to clean up the pits and grooves. Maximum runout: 0.05 mm (0.002 inch).

VALVE SEAT
The center of the valve face should contact the valve seat in approximately the center. Check Cylinder Head Valve Seat and repair if necessary.