Valves

- Tools Required:
J 26900-4 Outside Micrometer
J 26900-1 Outside Micrometer

1. Inspect each valve for excessive wear, signs of burning, or distortion at the face and stem. If any of these conditions are apparent, replace the valve.

CAUTION: Do not use any sharp-edged tools to Remove carbon from valves. Be careful not to scuff or nick metal surfaces when de-carbonating.

2. Inspect Each valve for pitting and carbon buildup. If build-up is found, Remove from valve using a wire brush. If pitting is found, grind valve enough to Remove pitting. In some cases, pitting is so bad that the grinding necessary to clean them up will leave insufficient valve head thickness and render the valve useless.





3. Measure valve head thickness, using a outside micrometer. Standard thickness is 0.8 to 1.2 mm (0.031 to 0.047 inch). If thickness is less than 0.5 mm (0.02 inch), replace the valve.
4. Measure overall valve length using a outside micrometer. Standard intake valve length is 87.45 mm (3.4429 inch). If the intake valve is less than 86.95 mm (3.4232 inch), replace the valve. Standard exhaust valve length is 87.84 mm (3.4583 inch). If the exhaust valve is less than 87.35 mm (3.4390 inch), replace the valve.
5. Measure valve face angle. The standard face angle is 44.5 degrees. If the face angle is not 44.5 degrees, grind face angle to 44.5 degrees.
6. Measure valve stem diameter using the outside micrometer. Record measurements to calculate valve guide oil clearance under Valve Guide Clearance. Standard intake valve stem diameter is 5.970 to 5.985 mm (0.2350 to 0.2356 inch). Standard exhaust valve stem diameter is 5.965 to 5.980 mm (0.2348 to 0.2354 inch). If any of the intake or the exhaust valves do not meet the above specifications, replace the valve.