Actually, I wouldn't be too worried. I have a fresh rebuild on mine top to bottom and my last motor (1jz) did the same thing. Crank and crank. No oil pressure building. So I took the oil feed line to the turbo off and laid it into a clear 2L bottle so I could see it from the drivers seat. I turned on the car, the oil instantly shot up and into the bottle. I literally had the motor on for 1 second. So in my humble opinion, I don't think there is anything wrong with the motor per say, I just literally don't think the starter makes the motor rev enough for the oil pump to make positive pressure. If you have oil in the motor and do what I did. You will not hurt a thing.