OIL PRESSURE RELIEF VALVE The oil pressure relief valve is located under the hexagonal domed nut on the front face of the cylinder block, directly above the starter motor .
If the valve plunger is not seating correctly, or the spring is weak, this will prevent the correct oil pressure (60 psi/4.2 kg/cm2) being maintained in the engine lubrication system.
To examine the valve, unscrew the domes nut with its folded copper washer and withdraw the coil spring and valve plunger.
Check the length of the spring. This should be 2.86 in (72.64 mm). Inspect the face of the valve plunger for pitting, and that the valve is seating correctly. Renew the valve if necessary.
If the valve is only lightly pitted, it can be lapped in on its seating using metal polish. A wooden dowel of appropriate diameter pushed into the open end of the plunger can be used to rotate it while lapping it in. Clean all traces of polish from the valve and seating when this operation is completed.
Refit the components of the valve assembly in the reverse order of removing.