Lack of oil pressure
Turbo Mini Forums

sorry but this is a long one - I have looked through previous posts and although they give me some guidance I want to be sure:
Problem: Complete engine rebuild completed and we were advised that Standard oil pump was man enough for turbo unit, therefore that is what we installed. Pressure was just over 60psi running, cant be sure of tick over pressure. The car was then sent off for tuning on rolling road, carried out by the same people who recommended oil pump. They tuned it to approx 90bhp and noticed that the oil pressure had drop to 10psi flat out, so stop the motor. They tried packing the oil pressure relief valve and found a "piece of swarf" in the camber. The washers on the spring did nothing to boost the pressure. We have since rebuilt the engine with new gaskets, oil seals, o'rings and another pump and new main and big end shells. Still getting bad pressure. 15-20psi at tick over when hot rising to barely 30 - 35psi at 3000rpm. The pressure rises VERY slowly. So we took out the oil pressure relief vale which is badly scored. Put one in from another motor, ran it up and same problem. Took out pressure relief valve and it is now also scored.
How can we check that the valve is operating correctly and were do we looked before a total strip down again. Even then we don't know what to look for.
Running 15w40 duckhams at mo.
We are suppose to be doing the italian job in this in about 7 weeks. If we can't sort it the we have to cancel.
Thanks guys.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Did you remove oil gallery plugs and clean them through?

Did you strip the oil pump that you removed to check it? What about the new one? Did you get oil pressure fully up before you first started the rebuilt engine? If you did not do this you may have wrecked the bearing shells. What oil pump did you use, most of the commonly available ones are junk, the only ones to use are those available from Avonbar.

Have you checked out the oil pick up pipe is not either clogged or sucking in air?

Something must be scoring your oil pressure relief valve causing it to stick, you need to find and cure this fault. You could try replacing the standard valve spool with a ball bearing from the inner pot joint, despite this sounding like a bodge it is a common modification, I have the exact thing in my own engine.

Did you fit a new oil cooler after rebuild (if you have one fitted)

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

Thanks tom, new oil pick up so hope that is ok, Mini speed supply so I guess it was correct. Not sure what make the pump is. New one seemed ok, the one we have just replaced was a bit notchy. Primed the pump by filling it with oil before installing it, then turned the engine over with no spark plugs to make sure that we had pressure, admittedly the pressure only reached 40 psi but we thought this was down to the slow revs. Will try the inner pot ball bearing tomorrow. Have to admit that I do not know what you mean by the oil gallery plugs but I will guess that the old man clean them out, if not will suggest that to him. Thanks again.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Sorry dangerous, did not see you post. the oil cooler is the same one that we had on the first build.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

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

my thoughts are with.......toms and danerouse

go for the Avonbar pump! (SUPAFLOW)
around 35 pounds

but ...................... sort the swarf problem ............................

PRONTO!

when you rebuilt did you check ure big end shells ? if swarf has got in there and damaged them you will lose oil pressure there. Iam with Benross get the avonbar oilpump (you would want the best heart in ure own body ) drop all the oil out, and flush the engine.
new oil filter. new oil cooler, or at least remove it and put the stock pipes on see if this helps. have you checked the magnet on the sump plug for swarf ? if there is loads there and you havnt covered any miles i would want to know why, infact having gone through the expense of building the negine, i would take it straight out !

EDIT:- not to insult you but did you torque up the big ends fully ? easy mistake to make.....?

Edited by Richie on 28th Aug, 2006.

______________________________________________________
TRADER HALL OF FAME
BENROSS...MINIMARK..WOLFIE (comic genius).....CARL....MARTPAUL.......AXEL
______________________________________________________
TRADERS OF SHAME
1 user....pm me 4 details

LEGENDS
MikeRace, Mini13

The engine never actually went into self distruct. The people doing the tuning noticed the pressure drop and stop it before this point. They suggested that either the oil pump was failing, the o'ring joint between the gearbox and block was leaking or the pick up had failed. So we took it apart to check all 3. Replaced the pick up, and obviously resealled the o'ring joint when we put the block back on the gear box. As a matter of course whilst the engine was apart we replaced the big end bearings, but there was no damage and also inspected the main bearing shells, but they looked fine so dropped them back in. The big end bolts were torqued up and checked twice because we have fallen into that trap in the past with standard minis. we will replace the press. relief valve with a ball bearing and see what this does. I guess though it looks like a total strip down to ensure that there are no bits of swarf in there anywhere, although there was no evidence of this on the sump plug or in the sump.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

did you inspect the pump to see if it was badly scored U/S ??

There was no scoring on the pump. We put a bearing in the oil pressure reief valve and managed to get the pressure up by about 10psi to 45psi when cold. At tick over with oil temp at 75-80deg, pressure was 22psi. It also rose quicker, but not nearly as quick as it should. The only concern is still that it does no rise when the engine is revved. I have ordered a replacement oil pressure valve kit from avon bar as I am convinced now that the piece of swarf found was a part of the oil pressure valve seat. Guess this may explain why the pressure still is not great. Will try the kit then have to move on to oil pump etc.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

running 10/40 wont help matters though especially if the pump is shagged, if you had swarf issues at the relieve valve then the pump will be shagged.

the best pump i have used is the AE steel backed standard slot drive oil pump.

always looking for them bigger bunches of bannanas

could the seat in the block where the relief valve goes in be scored?

The swarf issue was on the original pump. We have rebuilt since then with a new pump and a clean engine, there was no evidence of swarf anywhere in the engine.
I think maybe it was a scored or maybe chipped(hence the swarf) relief valve seat.We fitted the replacement relief valve and had excellent pressure, infact too good. Adjusted the spring length and got the pressure down to 65psi. The oil still takes a fraction longer than expected to rise, but i think that this will have to be a hi capacity oil pump before we go to italy. For now atleast the car is on the road. thanks all.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

did you measure the clearence on the new big end bearings with plastiguage when you fitted them. perhaps the crank had been re ground previously and youve fitted standard bearings? just an idea.

did you put a gasket between the top of the oil pick up and the gearbox casing.

no longer a series, but still 1.3 turbo.