Ok, here is some more information on my oil pressure issue, and thanks everyone for so far helping out:
It is a 2 liter type IV in a 914, age unknown to me, it came out of a car I recently got rid of, ran great powerwise, didn't burn oil, and is now going to be put in another 914. Compresion tested hot was 120 psi, even on all four. valves kept there adjustment between 3000 mile checks very well. use Mobil One 15-50 oil. Also had all stock cooling tin and seals in place
Only problem I noticed was low oil pressure when driven hard on the freeway. I'd get the point of getting worried at 30 psi at 3500 rpm. also had a unmarked oil temp gage, the stock type that reads from the bottom of the sump.
It appears from reading past posts, that I was getting the oil too hot, thus causing the pressure loss. To check my temps, I took a calibrated (calibrated by a friend at a NASA lab) thermal coulpe, and after a run in the car, stuck the TC wire downt he dipstick hole, all the way into the oil (which is pretty close to my dash gage sender in the sump). I then marked my dash gage with the readings I picked up from the calibrated TC in the dipstick hole.
What i found was my oil was getting at least as hot as 250F!, and it was only when my dash gage approached this number, did my oil pressure drop. When my oil temp was near 203F, or even as high as 234F, I did not have an oil pressure problem.
So I guess my real problem is oil temperature, anyone agree / disagree?
My iron pump, as far as i can tell is the bigger gear Type I pump (ie 30 mm gears, and according to posters on the list, is a melling brand. I have no idea if it is O-ringed in place, but can tell that the .004 inch gear top to cover distance is at the limit Bentley calls out for stock pumps (not counting the thin .004 papaer gasket). thus the pump is probably not a probelm here, right?
at any rate I need to determine why my oil temp is so high.
i think I should just go ahead and put the cover on the pump, and install the engine, and then add a head temp gage and see if there is a probelm there.
Before re-installing I want to re-oring the pushrod tubes, as they dripped a bit on the heat exhangers, and replace the crank seals, and oil cooler seals, just for good measure as engine is out of the car now. When i pulled the tin, I did find a small amount of leaves on some of the fins, and a little junk on the oil cooler, but it was very little, I cleaned that up, but do not think is was bad enought to cause oil temp problems (guessing less than 5% of oil cooler was blocked).
I have no idea of the engines compression ratio, but guess it is not way to high, as the compression test showed only 120 psi, and I do not have blowby, but this is not an absolute confirmation of that. (if compression test was 190 psi, I would figure it is a high compression engine)
also note that I have the stock distributor,(with a pertronix) and vacuum adv/retard works, and timing is set with a strobe as per factory, I believe it is 28 degress at 4000 rpm. Note I also once did try reducing the advance to about 24 degrees at 4000 rpm to see if it made a difference, and it did not change the oil temp gage reading. I also am running california 91 octane gas.
Maybe I will find a clog in the oil cooler gasket?
or maybe I will find once the engine is back in the car, a high head temp, indicating a problem, although I would be at loss to know what is causing it.
I assume if head temps are resonable, and oil temp is still to high (and pressure low when hot) I should add an auxilary cooler, but the question would remain, why is the stock cooler not enough?
any rate if anyone has some ideas, or suggestions, or thinks I am going about this right, or just plain going about it dead wrong, please let me know.
thanks in advance.
dave