Working on a customers car and it has oil pressure fits. When it reads no oil pressure it has none(at the guage port with the line off).
Eliminate the guage , oil pump (melling HV cast iron style) , bypass , guage lines , oil filter as they have all been tried to death. Oil pickup is in good shape and away from the bottom of the pan. Oil level is correct. Has 1/2" pickup in a standard center sump pan (7qt).

Its a 440 and when you start the motor it will be fine and the oil pressure will be fine until you turn the car off. The next startup it will have no oil pressure even if you rev it. Simply shut the car off and restart (some times 2 or 3 times) and its fine. It goes from 80 psi to zero then corrects itself right back to 80 again on a restart. Sometimes its fine for many restarts. There is no pattern to this.

Im puzzled and its wearing me out. No metal in the oil , pan has been off and its clean.

Any ideas before I tear it all apart?


Hutch