No 1 Inlet Valve was leaking and we found the Valve seat was being pulled out of round when the inlet manifold assembly, which also accommodates the Valves, Seats and rockers was tightened.

In addition the valve seat wasn't concentric to the valve guide. The Manifold had at some stage been repaired and it was decided to machine the gasket surface and block to provide true flat surfaces as well as to re cut the valve seats true to the Guides.