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R32 GTS-T

RB20DET w/ 105000km's on odometer. Major service done at 95000km's.

About a week ago after coming back from a drive which had some hard driving i got a whole lot of white smoke (white smoke with blue tinge, pretty sure it smelt like oil) coming from the exhaust...it would mainly do it after backing off the throttle. And it would also do it on idle. I noticed that when on boost the turbo made a different whistle noise.

So i thought it was the turbo (It isn't a std turbo...but it's about the size of a 2530) and i took it off. There was no oil in the exhaust manifold. I took the turbo in to be inspected and the report came back showing only bearing wear etc and slight scoring on the seal plate. The seals were all okay. The turbo wasn't the problem, but i got it rebuilt anyway since they took it apart.

I have done a compression test which showed all cylinders having about 130psi except one which was at about 120psi. What is considered good compression?

If the turbo is okay, then I think this problem could only be caused by 3 things.

1. Oil pressure/flow is too great into the turbo?

2. Oil return line from turbo is obstructed?

3. Blowby?

I have a one way catch can set up on the engine (non-recirculating) and it had not collected much oil at all (hardly any), but i had noticed in the last couple months that the dip stick was having a tendancy to be forced out a little bit. Pressurised sump maybe? Could that somehow stop the oil from the turbo returning to the sump and be pushing it past the seals in the turbo to burn into the exhaust?

So how could i be getting a pressurised sump and not getting any oil back out through the rocker covers? Could there be something wrong with the crankcase ventilation system? Is there a valve or something which relieves the sump of pressure and directs the vapour up to the top of the engine?

I have the turbo back now ($660 later) but have not put it back on the car yet.

Some expert advice would be greatly appreciated!

Regards,

Scott

Edit: Pretty sure it's oil burning, not water vapour

Edited by MM2death
white smoke (white smoke with blue tinge, pretty sure it smelt like oil) coming from the exhaust...it would mainly do it after backing off the throttle.  And it would also do it on idle. 

sounds like valve stem seals

So how could i be getting a pressurised sump and not getting any oil back out through the rocker covers?  Could there be something wrong with the crankcase ventilation system?  Is there a valve or something which relieves the sump of pressure and directs the vapour up to the top of the engine?

check that all the breather pipe that lead from the rocker-covers are free from blockages

I had a similar problem on mine when running a catch can just of the cam covers and the PCV valve blocked

I used to run my oil level high as well which doesn't help

I set it up so the catch can still is in operation, but its now plumbed in between the r/h rocker cover take of point and where the air gets sucked in before the turbo if that makes sense! The PCV valve is still hooked up, so on decel, light throttle etc the crankcase air is still being sucked into the motor. So it filters the crankcase air going in before the turbo, and the other hose from the other cam cover is as it was standard

I have found this works well for me, the catch can has steel wool/stocking combo in it and gets rid of most of the oil mist from the blow-by. My intercooler/turbo etc have no traces of oil in them

I'd suggest trying this, mine has be running like this for almost 70,000kms at 200rwkw and it works a treat

Give it a go, worked for me

Chris

I set it up so the catch can still is in operation, but its now plumbed in between the r/h rocker cover take of point and where the air gets sucked in before the turbo if that makes sense! The PCV valve is still hooked up, so on decel, light throttle etc the crankcase air is still being sucked into the motor. So it filters the crankcase air going in before the turbo, and the other hose from the other cam cover is as it was standard

Okay Chris, thanks for the reply, but i'm a little confused as to how you have set yours up. Could you try to explain it a bit better. I'll post a pic of my current setup in a minute.

Scott

Yeah sure, this pic makes it a bit clearer!

You can see the l/h cam cover breather goes to the PCV Valve, like standard

Under boost, the PCV valve is forced shut, forcing the blow-by though the other side, into your inlet

This where I plumbeb my catch can in, it consists of a Greddy catch can, with a divider plate I made for the inside of it, one side is the inlet, the other is the outlet

Inside that is steel wool in a stocking, this gets rid of most of the oil from the air getting sucked into your inlet

post-493-1125449039.jpg

post-493-1125449150.jpg

Yeah, mine was setup just like yours, and it would smoke quite a bit. I changed it after reading up a bit on PCV setups etc

Popped the dipstick on mine too, and my compressions where ok. I was running the stock turbo when it did this, so it was ages ago

Try setting it up like mine, works fantastic for me.

I think i know what you're saying now.  So by my current setup, all i should do is connect up my PCV valve again and my setup should be the same as yours.  Correct?

Regards,

Scott

Kinda, but your catch can must be sealed, and not be able to suck air from atmosphere, otherwise off boost, you will jsut suck up whats in your catch can

My setup is totally sealed, nothing goes to atmosphere, so its 100% legal too

Yeah, otherwise it will not work at all. Will need to be sealed, otherwise it will be like you are running bugger all vacum because of the air leak

Stuff a heap of steel wool in a stocking and put that in your catch can as a filter, should work no worries

What sort of catch can are you running? can it be opened up so you can put some steel wool in there?

post-493-1125450141.jpg

post-493-1125450211.jpg

Edited by Chris32
No not really lol.  Um only way to get steel wool in there was to push it through the hole.  A mate made it for me from stainless.

I will seal it up...otherwise my car will probably stall everywhere.  It's a one way catch can too.

Scott

Dunno if it would work then, as you really need something with two fittings so you can have a inlet and a outlet, otherwise it won't work because it won't be able to flow air through it. Best bet would be to get hold of a greddy copy or something from autobarn, they are pretty cheap and then mod it to suit

Or put the stock pipe back on and see if that works, alothough you might get a bit of oil in your 'cooler/turbo etc which wouldn't be good

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