Smoking problem

[Baz]

Well lads, my St has been gong great for the last 3 years,just coming across a problem that seems to be getting worse as the oil degrades

I'm telling the truth when I say it does'nt get driven hard on the road as it attracts to much attention etc. but when I use it on track I use all of the rev range in all gears except fifth as the straight is'nt long enough(or the gearing to long whatever way you look at it)

This car is maintained meticulously and everything is checked anything it being used.Oil ,coolant, water hoses etc .

When I have the throttle open on full boost no smoke,when I change gear a small bit of blue smoke (nothing major) but if I'm say in 3rd flat to the mat and let off ( the revs have gone to near the rev limit 7k rpm and then i let off) I get a big quantidy of blue smoke out the back and if I open the throttle slightly it stops,close it again and another small puff. While this is happening I'm still in the same gear and the revs are decreasing.

Would it be a crankcase beather problem?? Compression I think is still quite healthy on this engine although cylinder 1 is about 10psi lower than the other 3 cylinders. No loss in power since it was mapped over a year ago either

 

[Stani1029]

turbo seals i think so possible turbo rebuild

 

[imp124]

you didnt have that turbo long ago really? i take it you are still using the hybrid? seems very strange

 

[MLC2]

I'd suspect valve stem oil seals. High vacuum when you close the throttle drawing oil past them.

 

[Stani1029]

if its the valve stem seams check on startup to see if theres a puff of smoke

 

[Duncan]

I agree, valve stem seals generally cause smoke on gear changes....and mine has exactly the same problem when booting it in 2nd, 3rd, 4th. Probably does the same in 1st but its over too quickly to tell

 

[Ed]

Hi crank case pressure on my old ST engine caused exactly this... I had a cracked ring land, but the compression test came up fine.

 

[Baz]

if its the valve stem seams check on startup to see if theres a puff of smoke

Small little bit when cold for 10 seconds or so.The turbo's in about 2and a half years dont think it this tbh.@Ed should the breather system be addressed to combat the high crankcase pressure?

 

[Duncan]

I read Ed's comment as a ring problem not a healthy motor. I have done a compression test too and it is ok so I assumed it was not a bad ring problem (ie mine is low but not rooted which I assume meant worn rings not broken ones). Will be interesting when I tear it down to see.

turbo seal is more likely to leak at high boost and high revs (ie before throttle closes) than after.

 

[Stani1029]

yeah i suppose, on my almera when the rings were gone the smoke was unbeleivable! and compression test showed up fine. ill leave the working out to the the others

 

[frank]

yeah i suppose, on my almera when the rings were gone the smoke was unbeleivable! and compression test showed up fine. ill leave the working out to the the others

maybe because the thinner oil rings suffer far more wear (rings in pics are from the same engine) so the compression rings are working fine but the oil control rings are,nt scraping the bore

 

[Baz]

maybe because the thinner oil rings suffer far more wear (rings in pics are from the same engine) so the compression rings are working fine but the oil control rings are,nt scraping the bore

Interesting Frank . . . . .I have a feeling it a breather problem on valve stem oil seals though

 

[linz0577]

easy way to tell is to run it and the remove the oil filler cap if you hear a puff of air you know its that. john

 

[imp124]

it will be an easy fix i think Baz

 

[Baz]

it will be an easy fix i think Baz

I hope so