Standard Procedure: Refacing
WARNING: This page is about a different variant/trim than selected.
NOTE:
Valve seats that are worn or burned can be reworked, provided that the correct angle and seat width are maintained. Otherwise the cylinder head must be replaced.
NOTE:
When refacing valves and valve seats, it is important that the correct size valve guide pilot be used for reseating stones. A true and complete surface must be obtained.
- Using a suitable dial indicator measure the center of the valve seat. Total run out must not exceed 0.051 mm (0.002 in).
- Apply a small amount of Prussian blue to the valve seat, insert the valve into the cylinder head, while applying light pressure on the valverotate the valve. Remove the valve and examine the valve face. If the blue is transferred below the top edge of the valve face, lower the valve seat using a 15 degree stone. If the blue is transferred to the bottom edge of the valve face, raise the valve seat using a 65 degree stone.
- When the seat is properly positioned the width of the intake seat must be 1.018 - 1.62 mm (0.0464 - 0.0637 in.) and the exhaust seat must be 1.48 - 1.92 mm (0.058 - 0.075 in.).
- Check the valve spring installed height after refacing the valve and seat. The installed height for both intake and exhaust valve springs must not exceed 46.0 mm (1.81 in.).VALVE FACE AND VALVE SEAT ANGLE CHART
DESCRIPTION SPECIFICATION SEAT WIDTH - INTAKE 1.018 - 1.62 mm 0.0464 - 0.0637 in. EXHAUST 1.48 - 1.92 mm 0.058 - 0.075 in. FACE ANGLE - INTAKE 45 1/2° - 46° EXHAUST 45° - 451/2° SEAT ANGLE - (INT. AND EXT.) 441/2° - 45° - The valve seat must maintain an angle of 44.5° - 45.0°.
- The valve face must maintain a face angle of 45.5° - 46.0° degrees for the Intake, and 45° - 45.5° for the exhaust.