oil pressure drops under load.
Turbo Mini Forums

Anyone got any ideas on why my oil pressure drops under load?

ildeing its fine and sits at 60 cold and 35/40 hot, but when its under load it drops down to about 5/10 then comes back up when you let off the gas.

i was using an electronic gauge so swaped back to my smiths one and its still the same, so that rules out dodgy electrics/sender.

took the pressure relief valve out and its pretty scored, filed allt he high spots off so it wont stick but it's still doing it.

Nick.

Sorry F**ked up..

Edited by Doodmeister on 15th May, 2005.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

Cut your oil filter open and have a good look at the paper element for bearing lead and other suspect bits of swarf.
The oil pressure shouldn't be throttle sensitive but should be RPM sensitive. If it drops with RPM you have a problem.

Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe.

it will if the mains bearings are fucked, im afraid you have goosed shells so strip her down and have a look.

but do change oil filter first but im 99 % sure the shells are goosed.

always looking for them bigger bunches of bannanas

also make sure bud that the by pass valve ball bearing in the oil filter housing is not wedged open by some debris etc..........

or the spring may have broken! collapsed.

this seems the likley culprit

if you have checked this and changed the oil filter.
and there is still no joy!

suspect the oil pump faulty? or the bearings ?

i hope its not

keep us informed bud.

ben.

Edited by BENROSS on 15th May, 2005.

right, i've chopped the oil filter up and looked inside, there's hardly anything in it really, no chunks of lead or owt anyway. it's all pretty fresh to be honest as i did an oil and filter change before the riv run, so done about 1k miles since then. Still got the old filter from before then though so i'll inspect that one too. still got the problem with a different filter back on there though.

It's definately not an rpm sensitive problem, it starts to drop as soon as you pull away, say if i get it up to about 4k rpm then let off, it comes back to normal pressure.

Going to grab a new cup and spring for the pressure relief valve tomorrow if i get chance, i've also heard of using a 9/16 ball bearing from an inner CV joint instead of the cup so i'll grab one of those too just incase.

I'm kinda leaning towards fucked mains or big ends though to be honest as it does sound like there's a bit of a knocking at idle.

It's all come at a shit time aswell as i was made redundant 2 weeks ago so i'm skint, and had to give the works van back so i kinda needed the car to get me to interviews and hopefully a new job. looks like a i beeter raise some cash and get meself a £50 shitter with tax and test as a run about.

Nick :(

oh yeah, the engines only done about 4000 miles in total, so surely it shouldnt be fucked this quick?

£50 shitter sounds the way forward to me mate. Good luck with the engine.

bearings oval!

youe not using a old oil cooler

Metro turbo weekend driver,Mini turbo in the making again!

nah wasn't using an oil cooler, i wanted to fit a temp gauge first to see how hot it was getting so i could tell whether it needed one or not.

have been offered 2 998 engines though so the plan is to drop one of them in while i sort out the turbo lump.
Will i be ok using the turbo fuel system on a normal carb? what do you reckon i should drop the fuel pressure down to? its at 3.5psi at the minute. just block up the plenum connection on the reg i'm guessing?

i read on here that the 3.5psi is about the same that the normal pump puts out, dunno if its correct though

im not running an oil cooler either at the mo for the same reasons, might see about taking the temp tomorrow then

You could just bypass your electric fuel pump and provide a feed to the mechanical standard pump for now just to get you away.

Or the other option I just thought of would be to chuck the 998 in, and put your turbo and carb etc all back on, turn the mixture and boost right down and have a 998 turbo for a bit whilst you sort the 1275 out!!!!!

As for oil coolers, my view is that if Ausitn/Rover decided that the std Metro turbo needed one, our tuned up cars that get driven hard almost certainly do! OK I accept the correct way is to check oil temps and then choose a cooler to suit but personally I would go the route of fitting a cooler regardless and then get round to taking temps and removing it rather than the other way round.......
Cold oil for a long time will damage engines, hot oil for a short time will damage engines........

ok, guess what im doing tomorrow

Going down to the woods for a big suprise?

you got it!

Just a quick one before you start changing engines.

When I first fitted a turbo, I used a T-piece so I could fit a gauge and a switch for the light. the pressure reading I got was really low, I couldn't believe it as the engine was brand new.

After fannying around for ages it turned out that because the turbo was now being fed off the pressure gauge tap-off point there was a pressure drop across the T-piece, causing the gauge to read low even though the pressure was fine.

Because the T-piece was designed not to have a flow through it, the internal bore was tiny. Drilling it out cured the problem.

Worth checking how you are measuring pressure and what sort of T-pieces you have.

Wil

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

yeah my pressure gauge is T pieced off the same point as my turbo oil feed, but it's always been the same since i turbo'd the car, just used the blue T piece that comes with the goodridge braided oil feed.

It's been fine up until saturday night when i noticed it dropping, just took it easy on the way home as i thought it was the gauge/sender playing up.

I'll have a look at it anyway, anythings going to be better than ripping the engine apart.

just a nother thought bud

could be the turbo bearings worn not the mains and big ends ?

you say its a good engine not done any miles at all?

could be the blower dumping all the oil to sump under load ???

hehe, i was talkin to my mate last night and he suggested that as its doing it under acceleration, so when the turbo is spinning up.

it has been smoking for a while which i put down to the turbo as its totally unknown, no idea on the mileage of it etc. might see if i can borrow a turbo of me mate and give that a quick try.

basically i'll try and rule out every possibility before pulling the engine.

Or how about borrowing a NA exhaust manifold or an LCB to fit to your engine to eliminate the turbo altogether?

yeah definately worth a try

dropped the oil tonight and the sump plug was pretty much swarf free (never seen it that clean to be honest) except for 3 chunks of metal in the pic below. we also filtered the oil after it was dropped but there was nothing in it.

it really is knocking at idle now and sound slike its running on 3, has only been run for about 3mins max tonight.

anyway, what do you make of these bits of metal. Gonna strip it down now anyway as i suspect a knackered big end.

I think the top one looks like an old tooth, the middle one a monkeys hat and the bottom one a nasty scorpian.

Oh, and the one on the left looks remarkably like a 20 pence piece, amazing!

Wil

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

see i thought the bottom one kinda looks like a dinosaur