Oil Pressure to turbo
Turbo Mini Forums

Hi,
when warm my turbo engine blows out blue/grey smoke from the exhaust, it seems to do it while cruising at 2-300rpm an occasionally at idle, sometimes it will not smoke at all and other times it will,
It doesn't smoke much when under boost, usually not at all.

I believe the turbo seals are Ok, the drain is not blocked and I have just rebuilt the engine,

has anybody bled off the oil feed to reduce the oil pressure to the turbo, my engines oil pressure is around 60psi when warm and running above idle.

Does anybody know what the minimum oil pressure required to the turbo would be,

cheers guys.
Phil

Garret Spec sheet i have for a nissan T2 is 16psi minium...

Will check the Metro turbocharger spec tomorrow...

cheers Dave, very helpful

I think i'll try reducing the oil feed pressure to the turbo, I remember reading about tapping off the oil feed with another pipe, then with a restriction in this pipe to bleed off the oil pressure.

I'm thinking of putting a pressure relief valve in this bleed line (spare MBC) This will open around 20 psi, hence the minimum oil pressure at idle will never drop below 20psi. But when running above idle oil pressure wil open the valve and bleed off the high oil pressure. The amount will be set by the restriction in the line.

Hope this makes sense. Any ideas?

Just try one of the pressure regulator kits from minispares etc.

Bring the whole engine pressure down to something like 50/60psi max. Should do the trick id guess.

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=1992

Here is the T3 information from the Garrett Spec sheet for the metro instalation

so between 40 and 80 psi

but remember flow is VITAL!

alex

AlexF

Especially for a non water-cooled unit!

Interestingly, the RST S2 (water cooled) spec sheet says 60psi as the maximum, as does the T2 spec sheets...

Cheers Guys, thats excellent that dave,

I think i'll reduce the pressure by bleeding it off, (rather than restricting it) and see if is any help,

I dont really want to reduce the engines oil pressure,

I'll try it tonight and see what happens

Have you measured the pressure at the trubo...?

Alex

AlexF

Right, sucessfully reduced the oil pressure at the turbo down to around 40psi max, MBC worked in preventing the oil pressure droping at idle.
I used a pressure gauge in line with the feed. originally it was max 60psi.

Unfortunatly no effect on the smoke from the exhaust. So i decided to remove the turbo, I split it leaving the turbine housing still attached to the manifold and downpipe (mounted over clutch housing as per janspeed) Blanked off the turbine housing and ran the engine and took it for a run, smoke soon cleared up so I beleive its the turbo, theres alittle play in the shaft.

Does anyone know where I can get a rebuild kit from?

or a good cheap t3 turbo

AET in Wakefield are fast, reliable and cost effective.

I do rebuild kits for ?50. Thats if you feel confident in fitting it

Its not hard to do, i did it easy enough but havent tested it yet.

On a std setup your unlike to have high oil pressure causing a turbo to smoke!

Alex

AlexF

I need one today, i'll ring round see what i can find

Ok mate, no worries, could get you one there first thing tomorrow morning i reckon, ill just have to check stock before i confirm.

PM me if you want one.

thabks ive found one faily local thanks to Dave for a resonable price. Cheers anyway
Phil

Found the problem last night, one of the valve stem oil seals had come loose, going up and down with the exhaust valve.

The problem seemed to come and go and didnt burn oil as when the inlets seals go and oil is drawn through with the vacuum.

back to smoke free motoring at last, pheeew

Phil

Would of thought that means that the stems are getting worn? Seals help a fair bit but it "should" cope without them id say.

Nothing to worry about but one to consider next time you have the head off.

There wasn't that much play in the that particular stem, It recently had 4 new exhaust valves after the timing pully broke! But ive heard people only run 4 seals on the inlets, I dont know any other cars that do this, only something ive heard of with Minis. I'll change the guides next time its off and ive cash to spare.

I think on the turbos with the bigger exhaust stem they have a tendency to get stuck and become more of a pain.
I always put 8 on my NA and never have any problems at all.
May aswell for pennies!

Think it was jimster who had a problem with them sticking, could be completely wrong though!!!

hope this can help: how is the pulse from the rock cover when you are opening the oil fidding? if the engine is just rebuilt it could just need a run in before to let the rings bed in and then the oil will get out from the turbo easily and will not go out thru the seals.

Yeah I see what you mean but its fine now, not a hint of smoke, it was just the loose stem seal. You could see where it had leaked as the port was oily rather than sooty.

#You cant feel much pressure coming from the oil filler cap, (the best ive ever felt it) Its run in now after a couple of weeks and going great
cheers
Phil