As you can imagine since my turbos parted ways with there seal, ive been looking in the rear view mirror for smoke as much as the road infront waiting to see what happens. early reports were good did a few 5 mile round trips etc, at first there was a fair bit of smoke but then it died down, eventually the last few of those small journey's nothing. Which I was very happy with, yesterday I took it for a blat up the dual carriage way and back to see what it did again pulling well no smoke etc etc.

So today I took it for a proper drive, I drove it for about 2/2.5 hours covering about 80 miles of mixed driving and full throttle acceleration through several gears. So really todays the first time its got hot, properly warm. the first hour was all smiles and very much the same smoke free-ness as previously, but about an hour or 2in I started to get smoke again, not the same as before mind. Previously I had grey/blue smoke at low rev pull away and idle, uptil 3k when it cleared. This time Im literally only getting it on the overrun. which is intermittent, it DONT get plumes of grey everytime I downshift and engine brake, its only every now and again. Its also worse in traffic for example at 30mph on the overrun is worse than at 70.

The negative side of me is saying great the piston rings are on the way out, and that is now a new problem after ive just pulled the damn engine. The positive side of me is saying the following, you did a compression test pre turbo refurb, which came back very healthy, between 165/170 on all cylinders. The car has done around 100 miles since all that oil ended up in the exhaust, and this is the first time that exhaust has got upto full temperature. So im reasoning with myself, that its merely oil residue burning off still and the hot gases aren't passing through as fast so im seeing the smoke burning off like that.

I do have a habbit of being very paranoid and the reasoning strange things with myself.

Opinions please??????????

you'll probably need a few very hot cycles to get rid of all the residue from the last issue. Dont worry about it yet.

I went out for another blast this afternoon once it had cooled a bit, and im fairly sure your right now. on a hard pull a little comes out then clears then your fine on the overrun for a fair while then once its sat there warm with little flow it will do it. ive only done a total of 126 miles now. 400 miles time it might stop. I may still do compression to put my mind at ease over the rings.

keep driving it, :)

Pull your tounge out the back of your head.

Pull your tounge out the back of your head.

hahaha that z does go well mate, i nearly swollowed me own tongue!!

its suprising how fast a stock manual z feels when you've been driving euro boxes for weeks lol

its suprising how fast a stock manual z feels when you've been driving euro boxes for weeks lol

i know im sick of the damn clio now, 1.2 piece of shit! i want my 6 banger back!

250 miles now still got smoke on the overrun, possibly less though.

I can see me rebuilding this block over winter :( which means il be about a year behinf where I wanted to be with it. Grrrr

I can see me rebuilding this block over winter :( which means il be about a year behinf where I wanted to be with it. Grrrr

PCV valves? i get smoke if i give it hard acceleration but only after and im sat still, soon clears on a blip of the throttle, definitely not turbo related as it doesnt do it on normal driving conditions, you would know if it was piston rings and a easy way to check that would be to see if your dipstick is still in its pipe correctly after a good welly. pressure build up in the crank from leaky piston rings would pop that out.

 

Im leaning more to PCV valves as smokey turbos will gunk them up quite good. you may also still have residual oil in the plenum that only presents its self once its been pushed towards the back of the engine under hard acceleration. You will be suprised with the amount of oil vapor that gets everywhere when turbo seals are on the way out.

 

Here is a video of my blue zeds intercooler pipes and the oil that came out of just one side due to turbo seal failure.

 

Click image.

 

Check the lowest point on your intercoolers.

PCV valves? i get smoke if i give it hard acceleration but only after and im sat still, soon clears on a blip of the throttle, definitely not turbo related as it doesnt do it on normal driving conditions, you would know if it was piston rings and a easy way to check that would be to see if your dipstick is still in its pipe correctly after a good welly. pressure build up in the crank from leaky piston rings would pop that out.

 

Im leaning more to PCV valves as smokey turbos will gunk them up quite good. you may also still have residual oil in the plenum that only presents its self once its been pushed towards the back of the engine under hard acceleration. You will be suprised with the amount of oil vapor that gets everywhere when turbo seals are on the way out.

 

Here is a video of my blue zeds intercooler pipes and the oil that came out of just one side due to turbo seal failure.

 

Click image.

 

Check the lowest point on your intercoolers.

Ive got brand new pcvs, not oem though, I was gonns have a little look down the tubes tonight actially. If it was in the plenum though surely it would pourout on acceleation. This only shows on overrun on a hot engine.

Ive got brand new pcvs, not oem though, I was gonns have a little look down the tubes tonight actially. If it was in the plenum though surely it would pourout on acceleation. This only shows on overrun on a hot engine.

Ive got brand new pcvs, not oem though, I was gonns have a little look down the tubes tonight actially. If it was in the plenum though surely it would pourout on acceleation. This only shows on overrun on a hot engine.

 

You would think that but does happen as the plenum has pooling area's for the oil. i had the same once id changed engine and turbos over, luckily i took the time to check the intercooler pipe work, had i not, im sure i would of thought the turbos were at it again lol

Ive got brand new pcvs, not oem though, I was gonns have a little look down the tubes tonight actially. If it was in the plenum though surely it would pourout on acceleation. This only shows on overrun on a hot engine.

 

You would think that but does happen as the plenum has pooling area's for the oil. i had the same once id changed engine and turbos over, luckily i took the time to check the intercooler pipe work, had i not, im sure i would of thought the turbos were at it again lol

Is it possible for the pcvs to not seal properly so when your on vaccum on closed throttleitsucks oil out the valve cover?

Done some investigating today with the little free time I had. all of the intercooler piping is clear, or as clear as to be expected, certainly not over oily or dirty. The plenum itself has like a tidemark up the side but no visible pools of oil, the tide mark has ben there since I got the engine. Checked the oil level which is the same as it was 100 miles ago, but too few miles to tell hey but yeah. I also watched the oil pressure, at idle this stayed at the first notch, rising with the revs. The smoke on start up is pure white and I did a condensation collection by sticking some cold metal next to it, what was collected was pure water, with a little black dust, so I happy with that. I also had a look at the exhaust gaskets and joins theres no oil pooling round there or evidence of it. I also popped off the oil filler cap, the engine idle changed when this happened, I assume this is correct? I also pulled the dipstick whilst idling and placed my thumb over it, no pressure was felt, I take it this is also a good thing? I am as of yet to do a compression or leak down, however after even more reading today I would seem its not unusual to have traces of oil burning out the exhaust on overrun for upto 2000 miles! im confused as to why oil burns on the overrun, whether its simply more visible or whether theres something else to it :s

Oh and the pvc's.... Im not 100% confident on them as they are not oem. However I do feel slightly more positive.

Valve stem seals...They can leak down overnight but also on overrun when motor is pulling full vacume with throttle bodies closed

Valve stem seals...They can leak down overnight but also on overrun when motor is pulling full vacume with throttle bodies closed

 

would I not get blue smoke on idle at start up though? because i don't just normal condensate white clears after a few minutes of driving.

Steve I have a set of nearly new nissan pcv valves........yours if you want them foc:cool3:

Worth a punt bud, if you could bring them along on the rr day that would be awesome. Just dont trust these non oems. Do you need monies for that yet?

thought id update this, driven the car a fair bit this weekend, the smoke on deceleration has now stopped. 3rd and 2nd gear overruns from 50/60mph and not a hint.... what I am stil getting a touch of though is that characteristic grey smoke, after prolonged hot idle(cold idle its fine) if your stop start in traffic for example there is a small amount of grey smoke, looks like a cigarettes been left in the exhaust, then if you roll forward and stop you get a small roll of smoke, you can smell its oily, and it clears almost instantly.

However if I turn my aircon on, the problem magically disappears. To me this sounds like my rebuilt turbos are still letting by the tiniest portion of oil. However ive still only got 200 odd miles on the clock, since the rebuild. I Think I'm going to consider refitting some sort of cat or extra silencer to build some backpressure back into the exhaust system, the problem is tiny but im a bit picky. All things being equal il be fitting some gt525s in about 18 months anyways, if all goes to plan :) going for new chra this time though not rebuilt ones.