my oil pressure rising on boost
Turbo Mini Forums

just took the mini out for a run and noticed when im on 18psi the oil pressure jumps from 80psi to 120psi which is max on the guage, only does it when the boost comes in and doesnt do it on say 12 psi, also when it does it theres a misfire/leaning off sound and a puff of smoke out the back, it doesnt burn oil any time, nor does it smoke at any other boost levels, even if i was pushing through the rings i would'nt get rise on the oil press gauge through the crankcase would i? confusing me, only thing i could think of was the turbo seals, but its new and it dont do it all the time,

thats really strange as its not even rising by the amount of boost.
so even if there was a leak path you'd expect to go from 80 to 98 type thing.

80 is really too high anyway so it may be worth reducing it to say 50psi and see what happens then.

easily done by shortening the oil pressure spring.

yeh, i'll give it a go, been running like that for a year os so and no probs, thats 80 at about 4500rpm, it is very strange, would it rise by just the increased pressure if it was breaking past the rings or would it increase by a lot beacause of the increased comp ratio,? im going on the rollers in an hour and half and dont know whether too,

could the oil level being a bit too high do it?

edit* i wasnt lookin at my crappy gauge prop, it sits at 45 normally and its now risin to 100

Edited by miniman on 29th Apr, 2006.

scrap what i said about it rising by boost only, i had only just woken up. only thing i can think of is that the head gasket is passing near where the oil comes up from the block on full boost?

or somewhere there is a path between them both on full boost?

very strange non the less. wouldnt of thought rings passing would of caused this alone. infact i'm sure it couldnt but i may be wrong! lol!

the smoke will prob be oil seeping past the turbo seals as the pressures sky high, is your crankcase well ventilated?

"Turbo's make torque, and torque makes fun"

"did you know you can toast potato waffles?"

i have the normal breathers with kn filters on top, is this suffecient? iain i cant imagine it being the head gasket really cause id get serious signs surely????

if this has just started happening

i will go a long with iain sounds like the head gasket!

anyone else???

IF the oil gauge is taken from the same place that the turbo is fed from then surely the obvious place the pressure is comming from is the oil seal in the turbo. I.e. On boost the oil feed is getting pressurised dircetly from the tubo oil feed.

If it is this then the turbo could be getting starved of oil. It does seem unlikely, but a good place to look.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Thats a very good point.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Just because the turbo pressure is 10 to 15 psi has no relation on the internal combustion pressures, which will increase as the the boost rises, so could be head gasket.

I've had funny oil pressure readings ion the past caused by the union that the gauge is attached to having a small bore-size. I drilled out the union and it reads fine now. If you have one of those brass blocky unions it's worth a thought.

If you blocked up the oil feed it'd make no differance to the reading, and to get to 120psi the turbo would have to be feeding the oil system, which is impossible.

I think it's probably a measurement problem. But could be head gasket

Wil

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

valid point will try another gauge first

Sounds like head gasket

My brothers mini which 1293 non turbo has the same sort of problem runs ok at low speeds and revs but put your foot down and the oil was pissing out of the breathers and rocker cover cap, and was misfiring, in the end got so bad it started to drink itself dry in a couple of miles.

But i would have thought if your head gasket had gone surely with the pressure a turbo engine is under is far greater then a normally asperated engine you would have oil spraying out of all the breathers?

replace the oil pressure relieve valve first, then get a adjustable oil pressure end cap so you can set the oil pressure to about 75 max cold, then re check.

always looking for them bigger bunches of bannanas

lol, yeh it most certainly is, thats why i cant read em properly, have to watch roads round my way, b roads, its stop doing it as much now, doesnt do it all the time, just occasional, which makes me think it is just a glitch some where, just strange how it moveswith boost,