Low Oil Pressure

550SPYDER · 01-31-2007, 05:27 AM

I am hoping that it is a bad gage / sender... looking for some suggestions on other things to check.

Car runs, sounds awesome. Normal puffs of smoke on start-up, totally gone within 2 min. Zero oil leaks. On start, oil pressure is steady at 4. Acts normal until gets warmed up. Then pressure will not go past 2. At idle, 1 to 1.5 after warmed up.

Been dealing with the normal electrical bugs recently and need to replace the alternator/regulator (have to trickle charge every night). Oil level is spot on, burns maybe 1 quart every 4,000 miles. I know the pump is working because front mount cooler and fender mount cooler are both hot after driving.

Changing oil this weekend and will check. 1. Debris in Oil Sump. 2. Debris in Oil Tank. 3. Debris in Filter. If all clear, can I expect that it is the gage/sender?

Thanks in advance.

NathanUK · NathanUK's Garage

Might be just a connection. Good luck.

550SPYDER · 01-31-2007, 02:32 PM

Thanks Nathan

WydRyd · 01-31-2007, 03:05 PM

All that sounds normal to me... my car does the same thing... it won't exceed 2bar once warm and @ idle.

I'm not quite sure about the puff of smoke upon start-up, for 2 minutes! Mine will only puff smoke occassionally and that's only for 5 seconds upon startup.

NathanUK · NathanUK's Garage

Maybe you are running very thin oil.

WydRyd · 02-01-2007, 02:58 PM

I run Mobil 1 5W-50 synthetic oil. No extended puffing upon start for me. Only does it occassionally and only for a few seconds.

I have no oil leaks whatsoever and I still get under 2bar oil pressure @ idle, once at operating temps. I believe this is normal.

550SPYDER · 02-02-2007, 04:17 AM

Thanks guys - running Royal Purple XPR 20/50. Going to the shop on Tuesday to check - and replace the Alternator.

NathanUK · NathanUK's Garage

What oil pressure do you get at say 3K RPM when hot ?

911rudy · 06:50 PM

The manual says that it is not uncommon for the low pressure oil light to come on at idle once the oil is hot. I'm not sure what the pressure is to turn on the light but at 1,000 rpm you are looking at 1 bar or less with hot oil. Also remember what happens when the oil gets warm; the entire oil system is opened up so that the volume of oil and the lenghts of tubing are much greater than when it is cold. Then you have the friction and drag of the circuit but the oil pump is only turning over at low rpm. On another note, I bought a new temp and press gage from NHS and my temp went down 75 degrees and my oil pressure went up .5 bar.

930gt-40r · 930gt-40r's Garage

1-1.5 bar oil pressure at running temp and a quart every 4k is very normal

550SPYDER · 02-05-2007, 04:17 AM

I really appreciate everyone's help with this - Nathan, Oil pressure at 3,000 RPM = 2 bar, had it up as high as 3,300 RPM - still 2 bar oil pressure - didn't push it any further. Rudy, I do feel that it may have something to do with the 25 year old gages and sending units, but also wanted to get inupt on anythign I might be on the lookout for or that I had missed.

NathanUK · NathanUK's Garage

20-50 is a thick oil. I run a thinner oil (not synthetic though) in my 3.2 carrera. I get 4.5 bar at high rpm.

On my 930 oil pressure was similair but I do not know what oil was in it.

You might have a problem.

930turbo · 930turbo's Garage

The oil light switches on @ .5 bar or about 7 PSI. My theory on oil pressure is; if it doesn't knock or explode, it's suffecient. Enjoy the ride.

WERK I · WERK I's Garage

Check your wiring while you are at it. When the engine is up to temp, watch your oil pressure gauge while you turn your headlights on and off. If you get different pressure readings, you have a wiring or alternator issue.

pavulon · 02-08-2007, 02:23 PM

So, if rebuilding and one wanted to carry greater oil pressure as insurance, what are some good options?

550SPYDER · 02-08-2007, 02:38 PM

All - just got off the phone with my wrench and there is GOOD NEWS! All seems to be well and related to a loose connection on the alternator. Gage operates at 8 volts and - didn't know that - and when I would get home the meter would say 6 or so - thus low oil pressure reading... wshew...

550SPYDER · 02-08-2007, 02:46 PM

Pavulon - read an article in Excellence about a wicked 930-505 that S-Car-Go built a couple months ago, they moded the case for a 964 pump I believe. Other than that, I am not sure that there are other options and now that I think about it - you really wouldn't want to do that anyway... As, you would only be masking what is a most possibly a MUCH larger problem. It's kind of like those extreme makeover shows where they make really ugly people pretty. Why, well because some poor guy is going to see her, say, man she's hot, marry her, and have kids - Damn UGLY KIDS. So, for the sake of the children don't mask an ugly problem with a pretty gaget.

pavulon · 02-08-2007, 03:33 PM

You lost me...How is an accurately reported higher oil pressure at operating temps a bad thing? I'm not talking crazy high pressure but 7 psi at idle seems marginal to me...but I would not claim to be an expert....just trying to learn is all.

930turbo · 930turbo's Garage

You can change the fittings at the cam towers with a newer version that has a restrictor orifice built in. This will improve your idle pressure. Wanye has them in the catalog PEL-CAMRSTN. You can ID them by a groove in the center of the hex portion of the fitting. Check yours before ordering to be sure they haven't already been changed.

930gt-40r · 930gt-40r's Garage

Quote:

Originally posted by pavulon
So, if rebuilding and one wanted to carry greater oil pressure as insurance, what are some good options?

If your refering to engine rebuild, you could put a nice shinny GT3 oil pump in that flows a higher volume. I swear I have seen them online somewhere for $8-900. Its a one time insurance premium.