low oil pressure
Turbo Mini Forums

Hello
Well, finally got the engine running sweetly, but now up pops another biggy.

On start-up, the oil pressure reads about 80psi, which is fairly normal for a cold start. Was the same on my previous mini. But as the engine gets hot, about 80 deg c on the gauge the oil pressure just drops away to next to nothing at tickover and at best 25psi when revved up a bit. I don`t even think the rockers are getting wet either.

I bought this engine a while ago, all built-up fully re-conned, well thats what I was told. The piccys on ebay backed this up but now I am not so sure.

Any suggestions as how I go about solving this would be useful please. I can get it out but I don`t have the fully tec knowledge to find the fault. I know that it`s gotta come out, but I think I need someone in the Southampton area to go through it and sort it. Again, recommendations would be nice.

So close to finishing two years work, bugger.

Cheers

Id be checking the prv as a first place to check

13.95 1/4 mile on a 2.95 fd. Carnt be that hard to beat!

First of all what grade oil is in it?
But its generaly not good news the hot oil pressure is an indication of internal clearances
A couple things to try though pull out the oil pressure releaf valve clean it and the seat it rests on ( may be stuck open slightly )
Try thicker oil if its going to get rebuilt but not yet some thicker oil will buy you a few thousand miles

If neither of these help prob best to pull it out and have the crank ground and new bearings might as well do the piston rings too as they maybe getting tired too

Yes i moved to the darkside

Instagram @jdm_brett

Yes as the guys state above go for the pressure relife valve it may have stuck off its seat a Tad with a particle of gear steel
Make sure that it slides in and out ok if there is any scoring on the valve file this off

Other than that you need a strip down the shells main bearings and big ends will be goosed!

Infact my bet is its an engine that's just been painted and sold what has done star ship miles sadley!!!

Gonna give the valve a try first.
Hate to think I have been rolled.
Paid a lot for this lump, cos all the piccys ,looked bang on.
Still need someone in Hampshire to look at it when it's opened up though.
See what happens tomorrow. Thanks all

It has been mentioned, but what grade oil is in it?

I had the same issue and it turned out to be the main bearings. The analysis was that moisture had gotten to the shells or fuel and caused the white metal to lift and brake off in areas. The engine ran fine but like yours the oil pressure was fine on startup but dropped to nothing when warm and only picked up when the engine was reved but like you it only achieved 20-30psi

Own the day

Ok,
Took out the prv. Unlike the pictures in both mini and metro manuals, I have the spring with a ball bearing on the end, and not the "cap" type as showing in the books. The length of the spring is 65mm as oposed to the spec saying it should be 72mm long.
Your thoughts please gentlemen.
Allan

For the sake of a few quid, I would replace it:

http://www.minispares.com/product/Classic/...k%20to%20search

the pressure relief valve controls the over pressure of the oil, usually only when cold is this ever open, or maybe at high rpm or if you have a massive oil pump

now if your current one is not seating at all it would cause your symptoms
the short spring wont be helping but may not be the whole problem,

^^ as andy says replace with the correct part and prey it helps, if not, all the above about a rebuild still stands

Yes i moved to the darkside

Instagram @jdm_brett

The problem is that it is a funny flat shape, the spring is strong, but not strong enough not to distort sideways under high pressure, or if swarf gets lodged in the way.

A CV ball bearing fits in nicer and seats better. Buy a new spring, cut off one "ring", slide in a small piece of steel rod in it (so to stop distortion) Happy days.

Edited by mattsmadmini on 19th Nov, 2012.

“A turbo: exhaust gasses go into the turbocharger and spin it, witchcraft happens and you go faster.” - Jeremy Clarkson

Yes fit the original. Spring an valve. ... those ball type setups are ill thought out, for. A standard block. All I have Delt with have never worked. I never use them. Consign it to the bin

Thanks for the advice gentlemen.
A new standard spring and end piece is now on order from mini spares. Gotta give this a go first.
I spoke to the gent I bought the engine from and he is very up-set at the problems with it. His manner tells me this engine was fully re-conned as he said , but with a mistake made somewhere along the line. At least I don`t have to worry that it`s a painted up high mile lump.
Let you all know what happens next when the bits get here.
Cheers

I used the ball, and the oil pressure gauge always fluttered. I changed bcak to the bullet and the gauge stopped fluttering. Coincidental?

Yes i moved to the darkside

Instagram @jdm_brett

Have we got an answer for what grade oil is in it!!!!!!

When mine was running i used the ball bearing and a cheap tim oil pressure gauge, i allways saw 20-25 at tickover when hot and it was a worry. ive had the big ends out since 1k of driving and they were fine.It allways shot up with the revs.
I used castrol rs 10/60

rick

Oh dear,
Fitted the new relief valve set-up.
As the motor was warming up, it when clunk clunk rattle clunk, knock knock knock.
My money is on the oil pump going tits up. We have a good engine shop near Southampton and his price for sorting it out was ok. Just gotta give him the block is all
Think I know what I will be doing next Saturday. Still, opportunity to change the diff ratio and fit a cross pin.
Let you know what is was when I find out.
Thanks for all the help so far.

Pisser!

I run a supercharger and I don't care the TB is on the wrong side.
VEMS + 12 PSI + Liquid Intercooler = Small Bore FUN!

Never wanted to say this but nearly all the turbo blocks I have taken apart have had a loose centre main was going the oil relief thing was your issue. Sorry to hear this.

Own the day

Thanks for the kind words.
Well at least I will know for sure that the engine has been rebuilt properly now and with a few mods that I was going to do over the winter anyway. The young fella that works on the counter of my local garage used to race mini`s a while back, with his dad building his engines. He has offered to assist me with all the tec bits I don`t know, so thats a bonus. Just gotta do it.
Cheers