Smoke when off boost, fine on boost and idle / static rev

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Big Daz

New Member
Got an issue with my R that I am looking for help with please;
When on track I am getting blue smoke out the exhaust after being on boost and coming off the throttle onto the brakes, no smoke on boost or during idle / tickover or static revving.
On removing the top intercooler pipe off the turbo, there is oil.
Its a brand new turbo, which has been checked and is working correctly. Compression test shows 160 +/- 2 psi across the cylinders, leak down is 5, 15, 8, 12 approx.
I have a catch can fitted which does not vent to air at all, 2 pipes, one from the top of the rocker cover and the other from the G/Box breather. It also has the wee black box between the block and the rocker cover still fitted.

My initial thoughts are valve stem seals, but as its not smoking all the time, I am not convinced, so next thought is breather issues.

Any suggestions / experiences?

Cheers

Daz
 
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pulsarboby

Guest
sounds like a turbo prob to me
if i were you i would remove plugs and check top of pistons to see if they are wet with oil
if so then it could well be stem seals letting by

also unbolt the ex manifold to see if any of the ex ports are wet with oil
 
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Big Daz

New Member
Hi Bobby,
Aye, done most of that - thats why its confusing me!
Plugs and tops all dry - starts and runs fine. I just refitted the manifold / turbo etc yesterday after it was away getting stripped and checked (its brand new and only done 4 miles)- given the all clear. exhaust ports are slightly sooty but no sign of oil or dampness. Confusing the hell out of me, hence why I am thinking its maybe breathers rather than seals.
 
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Big Daz

New Member
Yep that was my 1st thoughts too, but its a brand new turbo, but just to be sure it I removed it from the car and sent it to an independant specialist (one of the biggest in the UK) to check out and they confirmed its in perfect condition. any way that oil could be forced past them by having the breathers wrong and pressurising the crankcase / head?
 
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jambo_gtir

Member
That's what mine is doing mate. I re-built the turbo with a £30 rebuild kit and it solved problem for a while. It's started to come back again though.....
Check the oil return for the turbo? I had a mate who's return pipe was constricting and causing the turbo to leak oil.
 
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pulsarboby

Guest
yep as jambo said it could be restricting flow back to block possibly!

why not take the breather pipe off the catchcan so shes breathing to atmosphere (no possible crankcase pressure then) then give her a run round to see what shes like and if it makes any difference, if not then it has to be a tubby problem
 
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Big Daz

New Member
pulsarboby said:
yep as jambo said it could be restricting flow back to block possibly!

why not take the breather pipe off the catchcan so shes breathing to atmosphere (no possible crankcase pressure then) then give her a run round to see what shes like and if it makes any difference, if not then it has to be a tubby problem
Click to expand...
I guess thats worth a shot :), as that hose is really quite soft and flexible (but its handy for the awkward refitting...)

Also that sounds like a plan, I have a sprint next weekend, so I try that then and see if there is any improvement. I'm getting sick of being black flagged :)
 
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pulsarboby

Guest
just say you didnt see the flag as too much smoke :lol:
 
warpspeed

warpspeed

Well-Known Member
sounds like the pcv sticking open on vacuum, unbolt it and soak it in brake cleaner or try another one
 
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Big Daz

New Member
pulsarboby said:
just say you didnt see the flag as too much smoke :lol:
Click to expand...
I didn't see any smoke - going too fast ;-) other behind me however.......

Ok, been looking at that PCV thingy, looks like that lots getting stipped off and junked too :lol: Extra weight and I think a pipe direct to the catch can is better suited to the car.
 
warpspeed

warpspeed

Well-Known Member
If you have a catch tank you should keep the pcv otherwise you'll be filling the catch tank in no time at all
 
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Big Daz

New Member
warpspeed said:
If you have a catch tank you should keep the pcv otherwise you'll be filling the catch tank in no time at all
Click to expand...
So better to block it off altogether then? Seen some threads on that, but opinion is divided. My thinking is - if its blocked off, is that not just going to increase my problem as all vapour is then going back into the engine?
 
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pulsarboby

Guest
dont block it off as it will create crankcase pressure

to test it get a pair of grips on the pipe and pinch it you should then hear the valve pinging back and forth, if not then it maybe jammed in which case just undo the union on rc then remove and clean it
 
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