Hi All, I'm looking for help and suggestions to find out what's gone wrong my my new engines oil pressure. The engine is a 308 block with a 355 crank. Someone else did the block preparation and built up the short motor. I checked the main bearing clearances and got those up to spec. I also installed a flat tappet camshaft. (Crane CCH-314) But I didn't touch the cam bearings. I also installed the oil pick up and an ASR sump.
The engine was run in and tuned on a dyno eight months ago. Initially we had no oil pressure and the dyno guy fixed that by putting a smear of vasoline on the rotors and removing the excess silicone that the short block builder(idiot) used. Oil pressure was very good from then on.
Over the holidays I finally finished installing it into the car. I've run it a couple of times in the car to check for installation problems, etc. But only in short bursts as I haven't had the full exhaust installed yet. Oil pressure has been OK until yesterday. I ran the engine around 1500rpm for about 10 minutes to flush the cooling system and install proper coolant. Towards the end of this I noticed that oil pressure was almost zero. I shut it down and let everything cool off.
Next I drained the oil and it looks ok. No sign of any metal.
Pulled cover off oil pump, all looks ok there.
Checked gauge, shows full pressure when the wire is earthed at the sender. The sender reads 75ohm at no pressure and drops to 25ohms when I hit the hole in it with compressed air.
Put new oil in and new filter on.
Peeked into the rocker covers, they look a bit dry to me.
Started it again after the oil change, still nothing. Shut it down after maybe 15 seconds. I couldn't hear any excessive noise from the lifters, but hard to tell with no exhaust.
I went to take off the new filter and it was full of oil. I unscrewed the sender again and oil came out of there too. So I don't think that the pump or pick up are the problem.
There are no external sign of any oil leaks or problems.
I suspect that the oil is bleeding out big time internally somewhere.
Any ideas? What else can I test for?
I am worried that this is going to be an engine out job along with another set of gaskets, etc.