Hope someone can help me. My car is a 1984 944.

I changed my water pump and now I have no oil pressure (it was fine
before I changed it). I torqued the crankshaft bolt to 154 ft lbs.

I took everything back apart and for a black plastic washer (I guess
this is what it is it is quite disfigured). It was located behind the
timing belt pulley on the crankshaft and in front of the washer in
front of the oil pump housing. I cannot find this part on any diagrams
of the crankshaft.

Any info would be great.

George Cox