Valve Service

Figure 21-Valve Seats:

The intake and exhaust valves have a 44.5 to 45 degree face angle. The valve seats have a 45 to 45.5 degree face angle.

Figure 20-Intake And Exhaust Valves:

VALVES
1. Inspect the remaining margin after the valves are refaced.





VALVE SEATS
1. When refacing 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.
2. Measure the concentricity of valve seat using dial indicator. Total runout should not exceed 0.051 mm (0.002 inch) total indicator reading.
3. Inspect the valve seat with Prussian blue to determine where the valve contacts the seat. To do this, coat valve seat LIGHTLY with Prussian blue then set valve in place. Rotate the valve with light pressure. If the blue is transferred to the center of valve face, contact is satisfactory. If the blue is transferred to top edge of valve face, then lower valve seat with a 15 degree stone. If the blue is transferred to the bottom edge of valve face, then raise valve seat with a 65 degree stone.

NOTE: Valve seats which are worn or burned can be reworked, provided that correct angle and seat width are maintained. Otherwise cylinder head must be replaced.

4. When seat is properly positioned the width of the intake seats should be 0.75 to 1.25 mm (0.0296 to 0.0493 inch) and exhaust seats should be 1.25 to 1.75 mm (0.049 to 0.069 inch).

Figure 23-checking Valve Tip Height And Valve Spring Installed Height:

5. Check the valve spring installed height after refacing the valve and seat.

VALVE SPRING IDENTIFICATION
The valve springs are of two different lengths and are wound in different directions. The valve springs are color coded, intake spring is right hand coil direction with orange dye on the top coils and the exhaust spring is left hand coil direction with a green dye on the top coils.

VALVE INSTALLATION
1. Coat valve stems with clean engine oil and insert them in cylinder head.
2. If valves or seats have been reground, check valve tip height (A). If valve tip height is greater than 43.65 mm (1.7185 inch) intake or 45.98 mm (1.8102 inch) exhaust, grind valve tip until within specifications. Make sure measurement is take from cylinder head surface to the top of valve stem.

Figure 24-Valve Seal And Spring-Installation:

3. Install valve seal/spring seat assembly over valve guides on all valve stems. Ensure that the garter spring is intact around the top of the rubber seal. Install valve springs, valve retainers.
4. Compress valve springs with a valve spring compressor install locks and release tool. If valves and/or seats are reground, measure the installed height of springs (B), make sure measurements are taken from top of spring seat to the bottom surface of spring retainer. If height is greater than 38.75 mm (1.5256 inch), install a 0.762 mm (0.030 inch) spacer in head counterbore under the valve spring seat; to bring spring height back within specification.