Need help understanding the workings of the M20 oiling?

[Old Man]

We have run the track car enough now to have broken in the engine and do the first oil change.

So my question is - When I pulled the oil filter off it was not full of oil and all most empty. I took the oil lines for the oil cooler off and they were empty also?

I have continually checked the head for oil flow through the rockers during the runs and it has always been good. We also checked it before ever starting the engine by manually running the oil pump with a drill motor.

So is the oil draining back into the oil pan because something in the oil filter adapter is not working correctly?

Thanks in advance for your help with this.


Just released I should have put this in the technical section - Jeroen you can move this if you want - sorry not fully awake yet.
Daryl

[Jeroen]

Moved! That is weird. AFAIK the oil filter is always in the loop, it may be that the oil thermostat is not opening but there should always be oil in the filter, I'd say abt 200-250cc, but it may be that only some 100cc runs out. If the head oil line is supplying oil to the cam lobes usually the oil is circulating. If you have an air pocket (once experienced) the head does not get oil.

[Old Man]

Moved! That is weird. AFAIK the oil filter is always in the loop, it may be that the oil thermostat is not opening but there should always be oil in the filter, I'd say abt 200-250cc, but it may be that only some 100cc runs out. If the head oil line is supplying oil to the cam lobes usually the oil is circulating. If you have an air pocket (once experienced) the head does not get oil.

This is what has me totally confused. That is why I am thinking the oil filter is getting filled up and oil is flowing through it - but then draining back into the pan through the pump when engine is shut off?

Thanks for moving sorry to give you more work...

[Jeroen]

But then the return valve of the pump would be bad? Did u check? And measure oil pressure?

[Old Man]

Cold start the oil press is 65 to 70 psi at 800 rpm ideal - drops to 18 psi when water is 200 degrees temp at 800 rpm. oil pressure comes up as soon as rpm goes up. So far only oil run in the car has been Lucas 30 wt. Break in oil.

[Jeroen]

ok and what do you know about the pump? Was it checked? Still have that return valve in mind, I believe the seating can get damaged causing it to stay open.