Low oil pressure at idle.....turbo the cause?
Turbo Mini Forums

Ok so on a brand new rebuilt engine that had a new metro turbo oil pump, done about 2-3k, Ive noticed I'm getting low oil pressure below 1500rpm it can almost drop to nothing on the gauge then picks up to 7-10 at 800rpm. If you hold it at 1500-2k it will rise to 20psi then driving around and higher revs it's 40-70psi

I've got a ball and spring relief valve.
I've sat in loads of traffic for hours at a time and can't say I've noticed the oil pressure.

It's a smiths mechanical gauge.

I'm guessing it's the oil pump but does anyone have any other ideas? Turbo? It's a gt17

Also when the engine was first started I had problems with it making was too much pressure at idle like 80+ cold so I trimed the spring down. I've tried a longer spring again and it's still sluggish and really low even when cold

If the pumps fucked can anyone shed any light onto what may have caused it?

Cheers

Edited by Custard on 14th Jan, 2015.

Dave the Cake

Tired a new oil filter?

If something is worth doing, it's worth doing half of.

No as it goes... I changed the oil at 300-400 miles but not the filter. Worth a shot you recon?

Dave the Cake

Yep before you start pulling things apart!

If something is worth doing, it's worth doing half of.

Change the oil too. If it's gone pissy then it will be harder to make pressure at low rpm.

Maybe the ball is not seated correctly.

Remove the spring and ball, do the nut back up, and crank for 5 seconds (with plugs removed) to dislodge any debris.

Put the ball back in and give it a few taps with a punch to see if that creates a better seat for the ball, then reassemble and try again.

If you change the filter, prod the pressure release ball in the filter head to make sure that's not wedged open, as this would give a pressure reading a few psi lower than it would normally.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Here is a set of operations that I performed to fix a very similar problem.

1) Undo oil pressure relief valve
2) Remove spring and ball bearing
3) Chuck Spring and ball bearing in the bin
4) Replace with standard items
5) Nip up retaining cap
6) Restart engine

Whoever came up with the ball bearing solution must have been trying to solve a problem, but what was it? All they cause is trouble; vairable oul pressure being one of them. The standard item is perfect for the job it was designed for. The ball bearing is not.

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

www.twin-turbo.co.uk

Well nothing good to report chaps.

I've tried the bullet valve and standard spring, shorter springs with the ball and longer springs. Tapping the ball/cleaning it out.

I've tried a different oil pressure gauge. Which read more of less the same, perhaps a couple of psi higher. But still too low.

Changing the oil and filter didn't do anything either.

Could it be anything turbo related?

I read that running a turbo without oil feed even for 5 seconds is a no go? As this would tell me if it's the turbo?
Cheers

Dave the Cake

I'm running a gt17 with no bov at 15psi

Is it possible the turbos worn and is causeing the low pressure at idle?

If so. If I stuck open the waste gate and removed the oil feed, would I be able to run the engine for literally 5 seconds to see if the oil pressure rockets to the moon?

Maybe even....clamp the compressor still somehow and remove the intercooler pipe off the plenum XD

Dave the Cake

Try it for nothing!

If something is worth doing, it's worth doing half of.

make sure that the paypass ball non return valve on the oul filter housing is not extremely Weak! or stuck open partially.

my money is not on the turbo, that would be last on my list, was the oil pressure ok when the the engine was built to start with ? if so it will be the main bearings goosed and or the oil pump has come adrift slightley on the bolts ................ let us know

The chances of it being the turbo is slim.

But 5 secs without oil at idle wouldnt be the end of the world

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Is there a restrictor in your oil feed? Maybe it's just dumping all the pressure out through the oil drain?

http://www.turbominis.co.uk/forums/index.p...tid=469104&fr=0

Ok so I just ran the engine with turbo oil feed disconnected and alas...no difference as you all suspected!

No I don't have a restrictor in the feed.

When the engine was built it made a lot of pressure with the ball and spring. Maxed out a 100psi gauge. So I trimmed the spring to bring it down to about 70/80

Dave the Cake

What was the condition of the oil when you dumped it? Metalic looking? Any metal on the magnet?

Take the starter motor off: Any sign of oil around the flywheel?

Do you run oil jets; if so, which ones?

I split my oil cooler core a few years ago on the way back from the rollers. Oil pressure gradually dropped on the way home, but pressure of just a few psi afterwards. Changed from 10/40 to 20/50. Obviously changed the filter etc. No tapping to the bottom end. I tried some of that oil treatment stuff...cant remember the name now but it restored oil pressure and I covered many miles like that.

my thoughts in my case are bottom end bearings and pump. That treatment may be worth a try for a short term fix??

Can't say anything seemed wrong with the oil tbh. Slight bit of swarf on the gb magnet but nothing unusual. I can't get the starter off due to front rad and fans and I'm not running oil jets (yet) I'm looking forward to stripping it, hopefully I'll find a conclusive answer. Will let you all no

Thing is Dan I wanna get it sorted before all the shows start as I don't wanna be worrying about it!

Edited by Custard on 15th Jan, 2015.

Dave the Cake

is there any difference between hot and cold?

had crap oil pressure in mine and turned out to be a shagged pump

Na no difference between hot and cold...

Dave the Cake

Did you use thread locker on the oil pump bolts? If not could be they've worked loose?

'Where does the engine go?'

Edited by BENROSS on 15th Jan, 2015.

With all respect to Steve Benross (and I know he mentioned longer bolts to allow for the spring washers) I have seen two examples where either slightly longer bolts were used, or the pump body was fractionally thinner, with the result that the bolts bottomed out before the pump was clamped up.

In one example the bolt had been tightened up ,probably too enthusiastically,and against the bottom of the hole and then sheared in service, again probably because of expansion of the alloy bodied pump. causing a serious oil leak.

Getting the broken bit out was fun !

Update-

Turns out it was my oil temp capillary gauge sender was loose.... Where it bolted into the back of the gearbox in the oil pickup gallery. Knocked it loose when changing down pipes.

DOH!
I stripped the engine anyway and checked the oil pump which was fine.

Back together and it made 80-90 psi cold at idle.

Nex saga is on the way to work this morning (first drive in it) my pot joint seems to have somehow shat itself and was skipping/self destructed with very light acceleration. Will investigate once home

Dave the Cake