0 oil pressure
 

I installed a motor in a car of mine that came straight from a running car. I installed it, and figured since it was running 2 days before I wouldnt have to prime it. Well, installed the engine in my car cranked it up ran for about 20 secs and never built any oil pressure. Hooked a gauge to it and it too read 0 psi. So what could have happened? Do I need to pull the intake and prime it? I dont see why I would now that it ran for 20 secs anyways. Could the pickup tube have come loose? I'd appreciate any input, thanks.

Hmm... Yeah, I would think you should prime it anyway. It can't hurt anything. If that doesn't work, come back. LOL

Are you sure the motor in question had oil pressure before it was disconnected?
Is it full of oil?
If the pickup tube came off and the pan is full of oil, you should still have some kind of oil pressure.

If the motor was truly running with good oil pressure only 2 days ago, priming it would be a waste of time.

Are you 12?

And it was, I got it from a good friend of mine, and yes its full of oil. Im at a loss, completely stumped. I guess Ill add another quart and see if maybe it will pick that up. In a freak incident could the pump have went out? I just dont see that happening.

It is incredibly unlikely that the pump could just go out like that.

You say you verified the oil pressure. Did you use a known working gauge on the oil port on the side of the block?

EDIT: Was this a complete long-block or a short-block? Was the intake manifold on?

I recently replaced my oil pump and it took a good 15 seconds to make pressure. Scared the crap out of me. Some pack the pump full of grease to make it build pressure faster. Maybe someone can speak to that.

Yup, and it was a long block, the intake was off because he took the motor out the top.

Could anything have happened to the pump drive gear?

That is what I am thinking. Was it removed? Possibly broken during the removal?

I cant think of one reason why he would have removed it, but ill give him a call later. But it seems that would be the one thing it would come down to, I've ruled out the pickup tube and cant imagine the pump going out. Has there been any cases of the drive gears getting ate up?

Ha! No, I'm not twelve. You said the engine was working before, but as Ram said, you don't know if it had oil pressure or not. Not only that, but just because the car runs doesn't mean you didn't get it from a place where it hadn't been primed before. Just sayin, but you're right, with the known details now it's unlikely.

He said he got the motor from a good friend of his out of a running car. If it was running, it most likely had oil pressure.

Priming has nothing to do with this situation.

this is a rather interesting situation

as quick as you can get the intake off i would pull it to get a look at the drive - from the information already posted here that would be my first and only guess at this point.,

Yes, I got that now, thank you for the clarification.

Well I yanked the intake off last night and to my disbelief the drive gear was gone, unbolted and missing. I was furious, called my friend and he was even more furious than I was. He said there was a man in his shop looking for one and he told him that he had none to spare. He called the local police and they're looking into the situation. But I had one laying around, so its together and running like a top. But thanks to everyone for their input.