Rb25 no oil pressure need serious help!!

[dreamin240sx]

What's up guys,

Ok so this is my 2nd rb25. My first one I just blew the ringlands in several pistons at the last event I was at. So I got a full long block from a good friend that got it from an importer but never touched it since he recieved it. So I got it in my car checked the compression which was 180 across the board. Now the issue I'm having is the motor is a s2 probably one of the cleanest I've ever seen haha. But I always do a pre start up check out on every swap I do. This particular motor will not fill the filter with oil or even get it to the feed line on the turbo!!! I'm using 20-50 weight as I always have with every Rb I've worked on. I know the pump could be bad or something in that area but I literally cannot get a drop of oil anywhere. Do I have to prime the pump or is there aomething I'm missing here. I'm just trying to avoid to have to pull the motor out if it's not neccesary please any advice is appreciated thank you