Hi guys, over here in UK with an 8 that is smoking a little blue/grey smoke when I rev it.
I've heard many times that it ends up being the turbo rather than engine in most cases. I've had a specialist remove air box, pull off turbo pipe & find no oil & insignificant movement in shaft. Does this mean the turbo is fine, or is there any other checks to make on it?
The compression test on engine showed 180,165,165,180 across cylinders. We used a bore scope to look deeper that revealed oil on pistons 1 & 4 (with the higher compression), looking at valves could see oil near edges. The specialist seems to rule out turbo & suspects valve stem oil seals, & can change without removing head.
Specs on car is:
HKS GTII KAI Turbo (less than 10k miles)
1000cc injectors
DW Fuel pump
& tuned to a modest 1.5 bar max making 380bhp.
The car drives smooth, with low down power, idles really well & doesn't burn oil between yearly changes. 73k miles on car.
Last thing I want to do is get valve seals done & still smokes, to find it is turbo. Turbo quite new but heard they're not the most reliable turbo's.

Thanks for any advice.

Steve

 

If there's a large puff of blue smoke on initial startup after the car has sat for more an hour that's a pretty normal symptom for leaking valve seals.

 

To expand on this, if it doesn't occur until the exhaust is warmed up enough to burn oil, its likely the turbo.

Smoke on start-up is often from the valve stem seals leaking while it sits and it gets burned during combustion. When it occurs after its warmed up some, its leaking into the turbine housing and burning from the heat in the turbine housing and downpipe.

 

-Smoke immediately on startup could be turbo or valve stem seals. It depends on the damage of the two.


-If the valve stems are shot, it will smoke immediately and keep smoking, if they are slightly damaged as in being hardened and not sealing well, it will take half a minute or even a minute to see smoke, as the oil gets thinner and goes though them, once it starts to smoke it will continue to do so through out idle as the engine is on vacuum.


-If it is the turbo it also depends on how deformed/damaged is the gas ring. It might smoke immediately, or it might take a bit longer for the oil to become thinner to go pass the ring, and get burnt/vaporized by the exhaust gasses on the turbine wheel area.


-I also gave you a reply on MLR, I do not know if you saw it, so I answered here as well, if you did not see it, check it out.



-In regards to idle smoke, there is a way to distinguish between the two. You can remove the oil feed from the turbo, before you start the car. Do not worry the HKS will not get damaged, it uses dual steel ball bearings with steel cages, there will be some oil inside the cages still, and the shaft speed is very low. Let it idle for 30 sec, do not rev the engine, if you do not see any smoke, it is the turbo.







Marios

 

Hi Marios, thanks for the in depth reply.

I'm not getting any noticeable smoke on start up after filming it this morning being left sitting overnight. I do straight away smell oil when I start though. So took for long drive, and I'm getting the light grey / blue smoke puff out whenever I rev it once warmed up. I also sometimes see it in door mirror as I pull away from lights etc. Also have noticed it while reversing up slope on my driveway, where I have to give a bit more rev (horrible paddle clutch) & slip to stop from stalling.
Most people say if it doesn't smoke on start up & only at revs when warm, then it's not valve seals, but I've seen some disagree with this. Went to get wheel alignment done today & guy who works there, said his previous Astra VXR smoked in the same way as mine, & new valve seals stopped it.
As I said previous, there was found to be no play in turbo shaft or oil in pipes. I do notice this zzooooooop sound (very faint & can only hear with windows open sometimes) from turbo now & then on light boost, which garage thought was strange so checked for turbo oil & play.

Could a leaky turbo leave oil on top of pistons? Any other way a turbo can be checked? People have mentioned with previous HKS GT2 turbo to be unreliable sometimes, mentioning oil restrictor pushing too much oil through seals or WG flapper not sealing well?

Just hoping to rule out turbo before going for new valve seals.

Thanks again

 

If it was leaking from Turbo can this still leave oil on top of pistons?
Only smokes once warm & revs, I took two short videos today of cold start up & rev once warmed up.

 

Any oil in the j-pipe? Any up near the throttle body/IC pipe?