[Tech Help] S52 isn't building oil pressure.

Hey guys and gals;

I'm at the end of my rope here. I just replaced my E30's heart with a freshly rebuilt S52.

Starts up no problem, but the dash oil light comes on after a couple seconds.

To diagnose, I want to trace how the oil moves through the engine.

Something like this? http://imgur.com/a/JB9ed

I'm wondering if a bad head gasket could cause the poor oil pressure?

Could missing piston squirters cause it? (I don't remember seeing those when it was rebuilt.)