Re: Oil pump rebuilder
Assuming that there are no leaks elsewhere in the oil supply network, the oil pressure for the entire system will be controlled by the weakest relief spring. The 8BA pumps have built in pressure relief springs rated for 80 psi. The 1932-40 blocks were built with the separate relief having a 50 psi spring. The oil flow will always seek the weakest point to relieve and that would be the stock factory relief with its 50 psi spring. You could theoretically have a 100 psi pump and a 10 psi block pressure relief……the system will always relieve at the 10 psi point.
Ford went with an 80 psi block relief spring in 1941. This was well before the 8BA pumps with their built in 80 psi relief spring. The block rear oil seals were rope instead of the slinger in 1941 so I suspect Ford felt it okay to bump up the system pressure since they were changing to the (improved) rear rope seal setup.
The 32-40 blocks may have worked fine at 80 psi with fresh new rear main bearings, but I’d be a little concerned about rear main leakage at 80 psi with the old style slingers and a worn rear main bearing.
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