What caused a sudden drop in oil pressure in my 1949 Chrysler?

Question:

l was driving my 1949 Chrysler with some regularity until I noticed a sudden drop in oil pressure followed by what sounds like an engine knock. The oil level is full and I change it regularly, so I’m at a loss for why the pressure all but disappeared. Can you tell me why this has happened? I intend to overhaul the engine (it’s a six) this winter and am wondering if you can direct me to a source for engine parts. I’d hate to invest in an overhaul only to have the same problem ruin another engine.

Answer:

I strongly suggest that you carefully examine every component inside your engine once it is apart for indications of what went wrong. Two areas that are likely sources of a sudden oil pressure drop are the oil pump and oil pressure relief valve. Examine the pump for any broken parts and measure its components including the body, rotors, cover, etc. Compare your measurements to the specifications in your service manual. The oil pressure relief valve is on the left side of the engine and should be disassembled and inspected. Look for a broken spring, an obstruction, a stuck valve or other indication of trouble. A possible source for parts is Antique Parts Cellar