Oil Preassure Questions

[IanB]

Hi everyone, Just a few questions about oil preassure:

I have a R32 GTR and when im driving along the oil preassure sometimes sits bellow the quater mark when not under heavy load - is this a problem? It generally only happens when im just granny-driving the car about and a good free-rev will generally increase the oil preassure - when giving it a bit more stick (still keeping to within the legal limits of the road of course) the oil preassure usually jumps up a fair bit, between just above the quater mark or just above the half mark, however I have seen it go higher.

if giving it decent stick it will normally stick on the 4 (halfway) mark.

What does this all mean and is it bad?

The car just got back from a major service at GT auto and they didnt say anything about it. Am I just being an old worrysome grandmother?

Thanks

Ian

[SECURITY]

theres no such thing as being a worrysome grandmother when it comes to oil pressure.

get it tested by a mechanic who has a manual oil pressure tester asap. it should be at least past the 6bar mark under load.

if it all checks out ok, then replace your oil pressure sender unit.

what oil are you using? thin oil tends to read lower oil pressure.

[IanB]

Im using motul 4100

Is there anything I should be looking out for in particular to indicate that the engine is not getting enough oil? in my last car tappit noises were a sure sign of this.

//edit just reading a another thread about an extra litre of oil... would this be a good idea as a stop-gap until I can get it tested?

Edited October 28, 2006 by IanB

[Cubes]

Get the oil pressure checked.

Throwing another litre of oil in won't bump up oil pressure.

Its a 'stop-gap' measure to prevent oil surge at the track.

[IanB]

More info:

On cold-start oil preassure is fine - it doesnt really dip down low until the oil gets hot - even then its only low during idle, sits just bellow the 2 mark on the gauge. Once you get going again it comes back up to anywhere between 1/3rd or 2/3rd's.

Will have it checked on monday however

[SECURITY]

it could be a blown oil seal in your turbo. low oil pressure could be caused by this.

open up your intercooler pipe connected to the front mount and check if theres oil in your pipes.

[gtrchick]

Wouldn't your car be blowing a f**kload of smoke if it was a blown turbo seal though?

[Duncan]

this is what the workshop manual says about oil pressure (for 7.5w30 oil). Thinner oil will show a lower pressure (eg 5w40)

[SECURITY]

not really while at the early stages, he said he's getting 2/3 up the gauge so thats around 5-6bar so it is still holding a bit of pressure. i'm only throwing the idea up as a possibility.

[IanB]

Driving the car around tonight it was alot better, it sat more or less on the 4 (halfway) mark everywhere I went so I decided to give it some stick, I did notice on WOT it was blowing a fair bit of smoke, but this was only in the higher RPM range (6.5k +) and none at all in just normal driving...

I will take the FMIC pipe off tomorrow and see if theres any oil in there. Should I take it off at the engine side or on the intake side of the intercooler? Additionally, will there be any oil leaking under the car anywhere if it is a turbo seal?

I have put a sheet down under the car tonight to check for drops.

oil seals can be bloody expensive, after buying the car 2 weeks ago I have allready spent alot on it in just maintaince (1.5k so far) so im really hoping its just me being a worrysome grandmother. The car was much better tonight driving it around in all conditions, under heavy and light load and at idle the oil preassures were comperable to my mates R33 GTST.

A bit of smoke is normal for a turbo car on WOT in high RPM is it not?

Or is that just wishful thinking on my behalf?

//edit on closer inspection of the manual there it says at idle there should be 1.5 kg per cm squared, 3 at 2000 RPM and 4.6 at 6000 RPM which, if it translates directly to what the gauge reads (eg 1:1) then thats exactly what my car is doing.

Edited October 28, 2006 by IanB

[Cubes]

How are you seeing the smoke? Revision mirror?

I know at night I can see a cloud of something from mine once it comes on boost.. Especially if theirs headlights behind.

I've sat behind mine with the other half driving, interestingly I can't actually see anything apart from the a little bit of over fuelling.

[govich]

My gauge behaves the same as you have described, and i haven't had any problems at all with the engine - doesn't use any oil. And i also get black smoke at high revs due to overfuelling from the stock ECU.

In short - i wouldn't think it's anything to worry about.

[IanB]

yeah im thinking it was just overfueling on the ECU's behalf, the engine sounds, boosts and runs smooth as a babies bottom.

Still, as has been said, one can never be too careful. That being said, I just had a major service less then a week ago and GT Auto has a good rep (they mostly deal with high preformance imports, there were 6 - 8 other skylines in their yard when I got there and another one on the dyno being tuned along with some stageias and a XR6T) and I doubt theyd miss something so critical as oil preassure, however I will certainly ask them what they did to make sure that it was a-ok.

And yeah cubes, it was in the rear vission mirror with headlights behind me, looked like a smoky tailwind - prehaps the GTR was just ripping up the dust on the road?

Edited October 29, 2006 by IanB

[Cubes]

Overfueling... Just because there's a little haze of black it doesn't mean its running rich.

Mines been tuned to a 12:1 afr and I can see an ever so slight haze.

To see this completely ignore the night time revision check as it really shows it up badly.

Get some one else (the other half) to drive the car with you in pursuit.