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914World.com _ 914World Garage _ low oil pressure once warm

Posted by: zeezee May 27 2009, 01:22 PM

Once warm my oil pressure falls below 10psi and the green light comes on at idle.
I feel hot air coming out the oil fill. So I suspect the oil is getting frothy and not able to do it's job.

I have carbs. Timing is adjusted to Pelical artical recommended 34ish* BTDC.

Maybe that's too much?

Just did an oil change to try to remedy this. It's not buring oil.

Posted by: Cupomeat May 27 2009, 01:36 PM

I am sure that the following information would be helpful for all these people to help you out.

1. What oil are you using?
2. Was the engine recently rebuilt? (or do you know the general health of bearings/oil pump?)
3. Do you know what pressure it is making at 2k rpm, 3k rpm?
4. Is there anything special about the engine?
5. Does it have a stock oil pump?

Answering these questions will help people to chime in and give suggestions.

Posted by: tomeric914 May 27 2009, 01:51 PM

What he said.

Even more basic than that, have you checked your oil level?

What RPM are you idling at?

34 deg is a bit much IMHO but that shouldn't affect your oil pressure. You're heads will have the issue.

Posted by: zeezee May 27 2009, 02:49 PM

Sorry - I did leave out a few details...
- I'm using 20/50 Castrol
- I've had the car for a year. it was rebuilt before that. they put 2.0 heads on a 1.7 case.
- Not sure I can vouch for the health of the bearings or pump - but startup/cold pressure is 40ish
- nothing special about the engine = 2.0L w/ dual IDF44 - runs strong.
- I believe it is a stock oil pump
- oil level is a hair above the top line
- idle at 1k rpm
- warm oil pressure @2k rpm = 20ish, 3k rpm = 30ish
- resent oil change (did not smell like gas) - cleaned a bit of gunk out of the sump screen

I take it that feeling air coming out the oil filler is normal?

I am using VDO pressure guage and a dual post sender (not sure of the brand). Many posts have suggested sender problems. I will try another sender or a mechanical guage.

Posted by: jmill May 27 2009, 03:10 PM

They say at least 10psi for every 1K RPM. I don't know who "they" is but that's a rule I always run with. I had a similar problem using multiweight oil. I went to a straight 30 weight and it got much better.

Posted by: Cupomeat May 27 2009, 03:22 PM

Well, one good thing to try to identify is what is the actual oil pressure at idle.

If it is 9 psi and your light is coming on, I'd say the sender is a bit conservative and you can ignore it (the light). If it is 4 psi, I'd say you need to think about looking at your engine mechanicals.

That being said, your 2k and 3k oil pressures are certainly acceptable, but not stellar for a solid lifter T4 (in my opinion, not even worrying about what THEY say).

SO, an old joke/adage that I have heard many times before is the following;

There are two kinds of 914 drivers;
- those who have oil pressure problems
and
- those who don't have an oil pressure gage.

Posted by: underthetire May 27 2009, 04:48 PM

Mine did the same thing yesterday. First run on a oil change with castrol 20/50 high mileage. It was just sorta flickering. Never did that with the diesel oil I was running before. I'll just run it till things make funny noises though.

Posted by: zeezee Jun 16 2009, 12:17 AM

A new sender seems to be the answer.

With 30W oil - and warm - I see 10+ psi @1000 rpm, about 40 psi @3000 rpm.
No oil warning light.

I'm choosing to believe the readings from the new sender are correct and moving on to the next thing on the to-do list.