hosrom_951

Right out of the owners manual:


And i was getting all paranoid when temps hit 210F on sprinted runs

But 0.5bar oil pressure is minimum is something new to me.

Fluidplay

Wow!! 0.5 bar is really low. Mine never get below 1.5 on a hot day, normally at idle it sits around 2 bar and at 4,000rpm+ it will get up to 4-4.5.

RKD in OKC

My ! lit up at 1 bar as my main and #4 bearing was going out and engine was hot after an autocross run.

bearone

wtf, go fast, more rpm's, more heat over a sustatined period and the oil thins out.

WHY DO YOU THINK IT'S RECOMMENDED TO LET IT IDLE TO STABILIZE OIL TEMPS, turbocharged acft have been doing it since ww2 and they did it while taxiing in.

87951

Bill N

Changing topic a bit, but I am curious...I know oil pressure drops at least in part because oil thins as it warms, but how much do the changing tolerances in a warmer engine also contribute? Any thoughts?

Bill

Minimal.

When an engine heats up, clearances get tighter. Tighter clearances at the bearings does increase oil pressure, as there is less oil leaking out the clearances.

However, when oil breaks down from heat, it thins far more that the reduced clearances can overcome. Then you have a two edge sword. No lubrication with tight bearing clearances. Or as it is known "a spun bearing".

Bill N

Thanks, Bill, makes sense.

Bill

M758

The comment about 4 bar at running is one reason I switched to AMSOIL in my 944 race car. with mobil 1 15w-50 I would se 3 to 3.5 at 6000 RPM part way though 20 minute session. With AMSOIL series 2000 20w50 raining oil I would set mostly 4bar an occasion just a hair under. That extra pressure when hot running is big reason for me to use the more expensive oil.

toddk911

Again, much of what we hear in here is WAY diffferent then the factory's opinion.

I was always told by my mech. that you want to see appx. 1 bar per 1K rpm.

So at 1K (idle) 1bar is fine, 2K 2bar, etc.

I have been told in here that anything under 2bar at idle and your engine is in bad shape. I tell my mech that and he always says "stop listening to people on the internet."

toddk911

Mobile 1 is NOT what it used to be and I have had leaks with Mobile 1 and then run ANY other oil and no leaks.

Also, just going from 40 weight to 50 weight I saw about .5-1bar increase in oil pressures; regardless of what brand I used.

Oh, RKD: I am back to using Lucas oil stabilizer thanks to your track story and saving the bearing due to you running it.

M758

I switched from Mobil 1 a couple years ago when the Mobil 1 was still good stuff (at least I think it was the good stuff back then). No leaks on rebuit motor, just that low oil pressure when hard running.