Oil pressure

no911 · 03-23-2006, 08:25 AM

Car is running great, but it seems to me that my guage may be reading high on rev? what are the usual suspects?

84 911 3.2 stock.

Jim Sims · 03-23-2006, 08:35 AM

cold, thick oil

no911 · 03-23-2006, 08:37 AM

think I should change it? Only been about 2500 miles.

Jim Sims · 03-23-2006, 08:40 AM

What oil type and weight are you running? What pressure versus rpm do you think is too high? With the engine warmed to operating temperature one should see from 10 to 14 psi per 1000 revs with the increase tapering off at higher engine revolutions. Jim

no911 · 03-23-2006, 08:43 AM

sure. Castrol 20/50. At low revs its fine, but at about 3500 it reads close to five and so on. I take good care of her, and she seems to be running fine. Wondering if the guage is going funky or if its another thing? thanks for responding.

Jim Sims · 03-23-2006, 08:52 AM

That's a little high; 5 equals five bar equals about 73 psi and I would expect around 3.5 bar or 51 psi. Is the engine fully warmed up? Oil change interval with natural oils like Castrol 20W50 is 3000 miles.

Jim Sims · 03-23-2006, 08:53 AM

Do you have the reduced size orifices installed on your cam tower oil lines?

no911 · 03-23-2006, 08:56 AM

That's how often I change it. I'm going to go ahead and change it see what happens. any other thoughts on the culprit??? Thanks.

no911 · 03-23-2006, 08:59 AM

I dont know. nothing has been changed like that recently on the car. She has 96k and is stock to my knowledge.

Jim Sims · 03-23-2006, 09:02 AM

Check and clean the wire at it's connection to the oil pressure sender (in the camtower oil line - right rear of engine).

no911 · 03-23-2006, 09:08 AM

ok. will post results.

livi · 03-23-2006, 09:23 AM

What you describe sounds a lot like my gauge reading. I have been told its fairly normal (by a local 911 "guru"). Be interesting to hear what the web gurus have to say.

Wil Ferch · 03-23-2006, 09:35 AM

Seems "within normal" range to me...but somewhat hi-ish..not really a problem.

BA always said 1-1.5 bar / 1000 rpm is where you want to be. That would be 15-22 psi / 1000 rpm.

Seeing "5" bar at 3500 rpm+ should indicate a healthy, good oil pressure engine....no ?

- Wil

Jim Sims · 03-23-2006, 09:54 AM

Seeing "5" bar at 3500 rpm+ should indicate a healthy, good oil pressure engine....no ?

Maybe or it could indicate a high resistance wire connection.

Wil Ferch · 03-23-2006, 01:40 PM

(1.5 bar /1000 rpm) x 3.5 thousand RPM = 5.25 bar....

...maybe not .....

what does the gauge do at other rpm's....follow the same 1-1.5 / 1000 rpm profile ???

Wil

no911 · 03-24-2006, 07:24 AM

it is about 4 at 3k rpms, 1 at 1k rpm and when it is revved to 4k rpms it is maxxed. any thoughts. working on her tomorrow.

Wil Ferch · 03-24-2006, 08:07 AM

If you ask me this sounds about right.....

Wil

no911 · 03-24-2006, 01:35 PM

thank you. I am going to do a oil change. See if there is anything different. Maybe its all in my head.

petrolblue83911 · 03-24-2006, 01:40 PM

Are those readings with the car really warmed up?-driven 45 min or so? I find that when the car is really warmed up I get about 1.1-1.2 bar/1k rpm or, around 4bar @3500, but especially with a nice heavy oil like 20/50 it takes a while to warm it up and get the pressure to settle.

no911 · 03-27-2006, 12:38 PM

i changed the oil and it subsided a little. Still running great. I felt it was a little high. I pay too much attention to this car. Thanks for all input.