5_108.bk Page 176 Thursday, October 4, 2001 11:45 AM
REPAIR INSTRUCTIONS Inlet and Exhaust Valves INSPECTION Refer to Figure 234.
Visually inspect valves for cracks, pits or other conditions that may cause improper operation. Check valve seat angle. Also check stem length, diameter and condition. 234
Figure 234 — Inlet and Exhaust Valve Details
VALVE IDENTIFICATION To permit positive identification, the exhaust valve has two stem grooves and the inlet valve has one stem groove. The valves are also identified by letters, “2” (20-degree inlet) or “Y” (Pyromet exhaust), which are forged in a slight depression on bottom face of valve head. INLET AND EXHAUST VALVE INSTALLATION
The inlet and exhaust valve head diameters are nearly the same size. It is important, therefore, that extra care be taken when installing these valves.
Page 176
With the new, more effective valve stem seals (446GC328), pre-lubing the seals and valve stems during installation is extremely important. Perform the following: r
Valve Stem to Guide — If valves are removed, lubricate the inside diameter of the valve guides by using a “bottle brush” coated with graphite grease. This is particularly important when both the valves and the valve guides are new. With an on-engine seal replacement, pre-lube the valve stems with engine oil while moving the valve up and down, prior to installation of the valve spring.
