engine and drivetrain New Engine Rebuild Oil Pressure Problems

[Preyupy]

It sounds like your pressure relief valve in the oil pump is not assembled correctly OR it has some wear and has stuck in the closed position.  You need to remove the pan and pump and inspect it. 

[felix_666]

You need to remove the pan and pump and inspect it. 

 

^^^^^^^^^^^

If that is directed towards me, as mentioned earlier in the thread, I have done this TWICE, on each occasion everything was assembled as intended, see the photos.

[Guest_anonymous]

I looked at some used oil pumps I have. They are two different type castings. The casting like yours with the relief tube sitting out the bottom of a washer has a longer relief bore, and, it does not have a casted stop up top for the piston to stop. The orange o-ring is the relief piston upper limit stop. If the relief piston takes a heavy enough rebound from the spring underneath it is possible for the relief piston to stick up top. If that happens it is also possible for the oil flow to directly by pass the pump and drain under the piston out the bottom tube. No oil pressure!

[AlanM]

It sounds like your pressure relief valve in the oil pump is not assembled correctly OR it has some wear and has stuck in the closed position.  You need to remove the pan and pump and inspect it. 

 

Actually I pulled the pump out and could find nothing wrong, relief spring was the same in thickness and length as another car that the pressure was OK on.  Reinstalled pump same problem.  Replaced pump with a brand new one, still the same.

 

Thought there may be a cloth jammed in an orifice somewhere, as I had bought it as a used race engine,(S14 head on M10 Block with 77mm billet short stroke crank) but I blew it all though with air so I knew the galleries were clear.  Removed the M3 filter housing that was fitted that allows a cooler to be fitted, and just ran a filter on an 02 housing, still excess pressure.

 

All up had the pump out 4 times, and still don't know what happens, but an external pressure relief solved the problem, just I don't why there is one.  I have built maybe 30 engines of different makes over the years and have reasonable experience, this just stumped me.  

 

The engine was run then on the track without problem until the thrust part of the main bearing died, mostly through the use of  very high clamp force on a 7 1/4" aluminium AP Racing clutch.