Valves

Valve Head Specifications:

Inspect

1. 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.

NOTICE: Do not use any sharp-edged tools to remove carbon from valves. Be careful not to scuff or nick metal surfaces when decarbonating.

2. Each valve for pitting and carbon buildup. If buildup 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.

Measure

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

1. Valve head thickness, using a J 26900-1. 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.
2. Overall valve length using a J 26900-4. 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.
3. Valve face angle. The standard face angle is 44.5°. If the face angle is not 44.5 degrees, grind face angle to 44.5 degrees.
4. Valve stem diameter using the J 26900-1. 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.