The cracked block in my 1968 series 1 4.2 DHC E Type was replaced with a later XJ6 block about 3000 miles ago. I have a problem now on startup after standing overnight with slow pick up of the oil making it necessary to disconnect the low tension lead from the coil to avoid the engine running for more than 10 seconds with no oil pressure registering on the wet oil pressure gauge.
I've had the sump off and "O" rings and gasket were OK the oil pump is fine as when it does pick up the oil 70psi + is registered when cold.
I've checked and cleaned the pressure relief and balancing valves in the filter block with a Carlton Autos filter fitted.
Does anybody know if a non return valve was fitted to later XK blocks?