smoking after decat - anything apart from the turbo seals? - Drifting forum

YashioFactory · 11-08-2008, 20:07

just decated my Z32,

(2 cats as V6)

it smoked on boost after as soon as drove it.

so thaught turbo seals.

drove it OFF boost today to work and back (30 miles total)

then boosted it when coming from the gym, and no smoke???

is it possible that it was just flushing some old shit from outa the exhaust?

or isit 100% turbo seals and just didnt smoke just now?

Going to put the cats back on this weekend.

NORFY · 11-08-2008, 20:16

some aftermarket exhaust parts have a very thin coating of anti rust stuff on them, could just be this burning off.

keep an eye on it for a week, sure it`ll be ok

YashioFactory · 11-08-2008, 21:38

hmm..

its had kakimoto cat back exhaust on there since ive had the car (cuple months)

the decat pipes are second hand also.

yea il see how it behaves after a week?

perhaps its just some oil that was trapt/slodged just before the cats?

and is just being flusht out?

or it is the turbo seals

Danny_Boy · 11-08-2008, 22:02

Leave it on idle when warm for a bit, i decatted my old old S14a and it smoked wuite badly but i think the seals where a bit weak and the coplete lack of backpressure was pulling oil through the seals. Once the car was revved the smoke stopped. I ended up putting a differene exhaust on that had more back pressure and it cured it.

HTH

YashioFactory · 11-08-2008, 22:18

doesnt smoke on ildle.

not when rev it right out in neitrul.

only on boost, which isnt good

i decated on my S13 before, as soon as started up car, smoke pored out of it on idle, boost all the time.

the turbo was shagged, smoked with the standard exhaust & cat onit.
Blitz nur an decat really braught it out lol

anyway my Z isnt no where near as bad as my S13 was.

il see what its like on boost tomorrow, if still smokey the cats are off back on.
smokey car looks shit!

healthy car = happy me

YashioFactory · 14-08-2008, 23:06

hmm...

still doing it, but not really bad.

think we all get the odd bit of smoke on boost?

long as theres oil in the car, and have an oil pressure gauge, ensure you sont burn off too much.

doesnt do on idle, or when revd out, so i think il just leave it a bit smokey now and again.

thanks anyway

Kenji · 15-08-2008, 16:24

Blueish smoke on idle = turboseals
Blueish smoke on boost = valve stem seals

That's what I was told when my 1JZ was smoking (did that on idle).
I changed my turbo's recemntly to HKS T3G twinturbo's and no more smokeysmokey.

gandyRX · 15-08-2008, 16:28

could be some of the spray they use when they weld it, mine smoked for a abit (about 1hrr) after it was fitted but then went away, i did notice that there was a slight oily residue on the exhaust and on the inside of the packaging before i put it on

NayAE86 · 15-08-2008, 16:41

De-catted my old celica gt4 and it started smoking.....turbo oil seals went, one 2nd hand turbo later and viola no smoke

SxBoi · 15-08-2008, 23:10

you sure its not overfueling causing the smoke?? check the injector connectors for corrosion very common problem which makes them overfuel

Vova · 16-08-2008, 00:00

The only reasones for (blue) smoke are:

1. Turbo seals -> allows oil into compressor which is venturied along into the cilinders.
2. Valve stem seals -> vacuum draws oil past the valve stem into the cilinder
3. Worn oil-piston-rings -> don't clear all the oil of the bore leaving it to be burned.

So its either one of those, good luck!

Ohw I forgot, there is a 4. Dwarfs at night opening your bonnet, taking out the plugs, spraying WD40 inside the cilinder, put everything back in, and feck off, videotape you driving away in the morning in confusion and laugh while sucking their trousers.

YashioFactory · 16-08-2008, 11:32

smoke isnt blue,

its grey.

only on boost, but not all the time?

reallly dont wana replace the turbos, as there are 2 of them, and its an engine out job on a 300zx.

as its not too bad, and only does it sometmes after hard driving,

ive come to the conclusion of leaving it. weighing the cats in for 100 quid.

i have GReddy oil pressure gauge, so can see when theres oil in there etc.

dont really give this car a hard driving often, more of a cruiser. but i like the power to be there! (3litre V6 TT)

thanks for posts, but its grey smoke no blue, and only after decat its noticible.

if was piston rings would have noticed it before i decated???

PS mods are:

Apexi intake, Kakimoto exhautst, decats.
Getting it chipt soon and then turning the boost up.

pics of my new car (Z32 TT)

royal · 16-08-2008, 12:29

Grey smoke is probably still the turbos, I think its something to do with if its burn't or not (? can't remember.). I had a kinked oil return hose on my Rex and it was smoking really badly grey until I sorted the hose.
Zeds smoking after decatting are pretty common. The shelf life of the turbo seals tends to be around 80-100,000 miles and decatting shows up weaknesses that were already there but not an issue due to the back pressure on the cats. If you stick the cats back on it'll probably be fine for ages.

YashioFactory · 16-08-2008, 19:33

thanks,

what about if i leave them off?

itl get worse, eventually,

or will they just be gone completly after 2 weeks or something?

i havent weighed them in at the scrappys yet, just incase.

but probably will next week, as the smoke isnt too bad

Vova · 18-08-2008, 19:50

I heard about a thing called a 'one wat valve trick' which is if I'm not mistaken, making a one-way valve for the oil-vapour-ventilation system so the engine can't suck oil vapour in but can expell it (one wat valve).

So you could try to route the cam breathers into a catch tank (or a soda bottle), blank off the PCV valve (you can unscrew it and put a 1/4" (iirc size) plumbing-plug in it, get it a a local hardware/plumbing appliances shop) and blank the intake-hose hole that is where the breather went into, a wheel nut usually fits. If this takes care of it, hooray!

YashioFactory · 18-08-2008, 21:46

Quote:

Originally Posted by Vova

I heard about a thing called a 'one wat valve trick' which is if I'm not mistaken, making a one-way valve for the oil-vapour-ventilation system so the engine can't suck oil vapour in but can expell it (one wat valve).

So you could try to route the cam breathers into a catch tank (or a soda bottle), blank off the PCV valve (you can unscrew it and put a 1/4" (iirc size) plumbing-plug in it, get it a a local hardware/plumbing appliances shop) and blank the intake-hose hole that is where the breather went into, a wheel nut usually fits. If this takes care of it, hooray!

did this on my S13!!

workd a treat! (on idle, still smokes on boost)

i was thinkin how to do it on the Z, do you happen to know??
il post on the 300zx owners otherwise...

Supercharged · 26-08-2008, 11:24

I also have a Zed TT (actually I bought it from UK) which runs with Kakimoto and decat pipes... It also smokes (grey/blue) when it's been running on idle for a few minutes... On boost there's no smoke at all. It's a common "problem" with the zed, so live with it, or put the cats back on...

Cheers,
Claus

11-08-2008, 20:07	#1 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	smoking after decat - anything apart from the turbo seals? just decated my Z32, (2 cats as V6) it smoked on boost after as soon as drove it. so thaught turbo seals. drove it OFF boost today to work and back (30 miles total) then boosted it when coming from the gym, and no smoke??? is it possible that it was just flushing some old shit from outa the exhaust? or isit 100% turbo seals and just didnt smoke just now? Going to put the cats back on this weekend.

11-08-2008, 21:38	#3 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	hmm.. its had kakimoto cat back exhaust on there since ive had the car (cuple months) the decat pipes are second hand also. yea il see how it behaves after a week? perhaps its just some oil that was trapt/slodged just before the cats? and is just being flusht out? or it is the turbo seals Last edited by YashioFactory : 11-08-2008 at 21:49.

16-08-2008, 11:32	#12 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	smoke isnt blue, its grey. only on boost, but not all the time? reallly dont wana replace the turbos, as there are 2 of them, and its an engine out job on a 300zx. as its not too bad, and only does it sometmes after hard driving, ive come to the conclusion of leaving it. weighing the cats in for 100 quid. i have GReddy oil pressure gauge, so can see when theres oil in there etc. dont really give this car a hard driving often, more of a cruiser. but i like the power to be there! (3litre V6 TT) thanks for posts, but its grey smoke no blue, and only after decat its noticible. if was piston rings would have noticed it before i decated??? PS mods are: Apexi intake, Kakimoto exhautst, decats. Getting it chipt soon and then turning the boost up. pics of my new car (Z32 TT) Last edited by YashioFactory : 16-08-2008 at 11:35.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11-08-2008, 20:16	#2 (permalink)
NORFY dorifto kingu! Join Date: May 2008 Location: faversham, kent Posts: 907	some aftermarket exhaust parts have a very thin coating of anti rust stuff on them, could just be this burning off. keep an eye on it for a week, sure it`ll be ok

11-08-2008, 22:02	#4 (permalink)
Danny_Boy spl dori master Join Date: Oct 2007 Location: Lordswood, Chatham Posts: 250	Leave it on idle when warm for a bit, i decatted my old old S14a and it smoked wuite badly but i think the seals where a bit weak and the coplete lack of backpressure was pulling oil through the seals. Once the car was revved the smoke stopped. I ended up putting a differene exhaust on that had more back pressure and it cured it. HTH

11-08-2008, 22:18	#5 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	doesnt smoke on ildle. not when rev it right out in neitrul. only on boost, which isnt good i decated on my S13 before, as soon as started up car, smoke pored out of it on idle, boost all the time. the turbo was shagged, smoked with the standard exhaust & cat onit. Blitz nur an decat really braught it out lol anyway my Z isnt no where near as bad as my S13 was. il see what its like on boost tomorrow, if still smokey the cats are off back on. smokey car looks shit! healthy car = happy me

14-08-2008, 23:06	#6 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	hmm... still doing it, but not really bad. think we all get the odd bit of smoke on boost? long as theres oil in the car, and have an oil pressure gauge, ensure you sont burn off too much. doesnt do on idle, or when revd out, so i think il just leave it a bit smokey now and again. thanks anyway

15-08-2008, 16:24	#7 (permalink)
Kenji dorifto kingu! Join Date: Dec 2004 Location: The Netherlands Posts: 860	Blueish smoke on idle = turboseals Blueish smoke on boost = valve stem seals That's what I was told when my 1JZ was smoking (did that on idle). I changed my turbo's recemntly to HKS T3G twinturbo's and no more smokeysmokey.

15-08-2008, 16:28	#8 (permalink)
gandyRX gripper Join Date: Aug 2008 Posts: 19	could be some of the spray they use when they weld it, mine smoked for a abit (about 1hrr) after it was fitted but then went away, i did notice that there was a slight oily residue on the exhaust and on the inside of the packaging before i put it on

15-08-2008, 16:41	#9 (permalink)
NayAE86 spl dori master Join Date: Aug 2007 Location: now in a gtst Posts: 382	De-catted my old celica gt4 and it started smoking.....turbo oil seals went, one 2nd hand turbo later and viola no smoke

15-08-2008, 23:10	#10 (permalink)
SxBoi gripper Join Date: Mar 2008 Location: Huntingdon Posts: 26	you sure its not overfueling causing the smoke?? check the injector connectors for corrosion very common problem which makes them overfuel

16-08-2008, 00:00	#11 (permalink)
Vova touge runner Join Date: Apr 2008 Location: Netherlands, in Maastricht Posts: 195	The only reasones for (blue) smoke are: 1. Turbo seals -> allows oil into compressor which is venturied along into the cilinders. 2. Valve stem seals -> vacuum draws oil past the valve stem into the cilinder 3. Worn oil-piston-rings -> don't clear all the oil of the bore leaving it to be burned. So its either one of those, good luck! Ohw I forgot, there is a 4. Dwarfs at night opening your bonnet, taking out the plugs, spraying WD40 inside the cilinder, put everything back in, and feck off, videotape you driving away in the morning in confusion and laugh while sucking their trousers.

16-08-2008, 12:29	#13 (permalink)
royal S1- F.T break! Join Date: Nov 2005 Posts: 4,819	Grey smoke is probably still the turbos, I think its something to do with if its burn't or not (? can't remember.). I had a kinked oil return hose on my Rex and it was smoking really badly grey until I sorted the hose. Zeds smoking after decatting are pretty common. The shelf life of the turbo seals tends to be around 80-100,000 miles and decatting shows up weaknesses that were already there but not an issue due to the back pressure on the cats. If you stick the cats back on it'll probably be fine for ages.

16-08-2008, 19:33	#14 (permalink)
YashioFactory dorifto kingu! Join Date: Nov 2005 Posts: 849	thanks, what about if i leave them off? itl get worse, eventually, or will they just be gone completly after 2 weeks or something? i havent weighed them in at the scrappys yet, just incase. but probably will next week, as the smoke isnt too bad

18-08-2008, 19:50	#15 (permalink)
Vova touge runner Join Date: Apr 2008 Location: Netherlands, in Maastricht Posts: 195	I heard about a thing called a 'one wat valve trick' which is if I'm not mistaken, making a one-way valve for the oil-vapour-ventilation system so the engine can't suck oil vapour in but can expell it (one wat valve). So you could try to route the cam breathers into a catch tank (or a soda bottle), blank off the PCV valve (you can unscrew it and put a 1/4" (iirc size) plumbing-plug in it, get it a a local hardware/plumbing appliances shop) and blank the intake-hose hole that is where the breather went into, a wheel nut usually fits. If this takes care of it, hooray!

26-08-2008, 11:24	#17 (permalink)
Supercharged gripper Join Date: Mar 2008 Posts: 22	I also have a Zed TT (actually I bought it from UK) which runs with Kakimoto and decat pipes... It also smokes (grey/blue) when it's been running on idle for a few minutes... On boost there's no smoke at all. It's a common "problem" with the zed, so live with it, or put the cats back on... Cheers, Claus