Nissan Repair: Oil Pump, nissan d21, pressure release valve

Question
Replaced timing chain on 91 Nissan D21 Pickup KA24E. Oil Pump wouldn't move oil through the engine so bought a new one and I still can't get oil flowing through the engine.  Any idea as to what I did wrong or what is wrong?

Answer
Chris,

The pressure release valve could be stuck open.  But, I would say you could get it working if you opened the oil pump and packed the gears with grease and reassembled.  Make darn sure the oil pickup is connected properly.  If there is even a slight gap it will suck air and you will have no oil pressure.  Run the oil pump by hand to make sure you have a good pump after you pack the gears with grease.  Now, after you get the engine running change the oil soon after to get rid of the grease.