Beach

Its nothin too bad as its had a recent engine and turbo...

When rolling down hills in say third gear using the engine to brake, when you get back on the throttle it gives a puff of blue smoke but then clears pretty much straight away.

Could this be the valve stem oil seals leaking ??

Thanks in advance

Alps Pacino

Its a cossie

On a serious note i havent seen a cossie yet that doesnt smoke a little, and i have no idea what the problem with yours is sorry

R4N SS

iTrader: (6)

they all smoke, but if you had an engine just done surely the stem seals would have been changed anyway.

Beach

Exactly my thoughts, dont know if they were changed 100% as the head came from a1 rally sport as the head they took off was fooked and it may have allready had seals in.

This all happened before i got the car though you see so i cant be certain.

Like i say just wanted to know if id got any problems

cossie4i+

iTrader: (15)

I get somke on the overun on mine when i have been given it large

Also been told i get flames

Steve.

pee vee

have you got a middle box in your exhaust?

Beach

No mate ??

pee vee

ive read, and heard it said that the turbo relies on a LITTTLE back pressure to keep the oil on board (backpressure caused by middle box i guess!?)
so if you aint got it,, on over run like you describe, that COULD well be
why it does it!!

Damo V

turbo or stem seals

Beach

Cheers Damo

Beach

Duno it sounds a bit strange to me as the backbox will cause very little if no backpressure as its a 3''bore

pee vee

yeah mate.
i mean, according to this tuners mag i was reading
it says the turbo seals rely on some back pressure to keep the oil in,
so maybe just the back box isnt enough?

dunno, i was skeptical too till the guy that rebuilds turbos
on here posted about it too


EDIT: but as damo and others have said, could well be the stem seals/turbo. but seems odd if they are all new.

Dunc Maclean

was a werid one ay beach. was kicking out quite a bit when u went down my hill after dropping me off

Dunc

p.s. it still was fucking quick as Mr yellow scoob found out ay mate

rs nuts

iTrader: (4)

mine does the same changed turbo still the same and the valve guides and stem seals are newish

mk2rstaff

sounds silly but is every thing still bolted tight to where it should be mate

i would expect a little poof of smoke on over run just build up of burnt gases and fluid in the exhaust? ever noticed someone driving down the road with back box having a pee same thing i believe

cossiecrew

beach you forgot to add it stinks of fuel all the time

R4N SS

iTrader: (6)

have you checked the breather is not clogged up as thats what mine was

Si B

iTrader: (59)

Mine used to do this a fair bit - had new Stem seals and brand new turbo.

On my old chip it did it a lot, and flamed A LOT.

Now on new chip and same turbo / engine and no smoke and very little flames. I know you said blue smoke (suggesting as per others Stem seals or turbo oil seals), but this is what mine did and was pretty much entirely over run fueling (part of the way the chip is set up.)

Sounds like you need a flamer kit fitted to burn off that nasty smoke!

Simon

Dunc Maclean

lol, i notice this everytime i go out in it

Dunc

Beach

Shit i think ive become used to the optimax smell and dont tend to notice it as everyone who goes in the car says it stinks but i cant find any leaks at all.

I know that it is mapped to have plenty of fuel as well but still think its oil, its only when you go back on the throttle after using the engine brake, fitting a new breather soon so ill just see how it goes

Dave Henshall

mine does the same with new exaust guides and stem selas, and turbo seals done, no smoke when idle or on power, just likeu say on over run down a long hil, then when u open teh throttle, a quick whiff of smoke then clear againb,

like aabove, its a cossie, and mine does have the centre section to my mongoos btw

frog

Stu once said that in those conditions, some "soot" is allowed to build up in the exhaust due to the low-ish air pressure in there. When you get back on the gas, the pressure increases and the exhaust clears itself, hence the puff.

Dave Henshall

would make sense

cossiecrew

strange to me mate but dont say i didnt warn ya dont want to be reading a its gone up in flames post

Beach

Dont know what to say, i just cant find a leak anywhere

I think its un burnt fuel that you can smell in the exhaust but i couldnt be sure

gibbo frst

iTrader: (2)

shit i just chopped the middle box out on mine as was so quiet now only has the rear box does this mean i may fook the turbo?? am i better off welding the box back in?

Damo V

Beach

WHat fuel lines do yuo run? std or aftermarket, as non PTFE aeroquip, "bleed" petrol fumes

gibbo frst
No dont worry, agreed turbo does require a little backpressure, but I wouldnt worry about it IMO

Beach

[quote="Damo V"]Beach

WHat fuel lines do yuo run? std or aftermarket, as non PTFE aeroquip, "bleed" petrol fumes

All standard stuff mate not done anything witht he fuel lines at all.

Which are the ptfe type then Damo ??

Damo V

Just more rigid than the "normal" aeroquip thats all

Beach

Cheers for that ill have to look into sorting those out in the future

Mad_Ad_300bhp

sounds like the problems i had, a little blue on the overrun or when u pull up to a junction after a good thrashing, started off very light but within a month u couldnt see behind you for the white smoke! allthough its blue smoke id say its your pistons but i could be wrong as im no expert

rabmc

Prettt sure the all do after giving it some , once u go back on gas u get a little puff

Not much though

Beach

What do you mean mate ??

The rings are passing or the pistons are fooked from being melted ??

rabmc

My bezzer mate had this problems and thought it was stem seals , but he was getting a large amount off smoke once he went back on throttle turned out to be rings

Sure he will reply to this to tell it a bit better

rapidcossie

what about worn valve guides??

would this not let oil run down the valve and into the combustion chamber?

was the head defo a full recon??

Mad_Ad_300bhp

Piston Rings mate, even when they are going fucked they should still last a for a while. When i bought my pulsar i had it about a 1 week, then decided to do a comp test when one of the electrodes came off one of the plugs. turned out 3 cyl's where around 160 and no 4 was only giving 60 psi. You could not tell any difference by driving it. ie there was no smoke and the power seemed to be there most of the time. I drove it round like this for a good 6 months of hammering @1.2 bar.

the mahle pistons in your cossie are 10 times better than the standard nissan shite so i wouldnt worry about it mate.

Damo V

Wasnt going to suggest rings as you said engine not long been rebuilt, but it is guite likely

Beach

Well i cant be sure at all as the head came from A1 rally sport and im told was fitted with new seals, not sure about guides though

Im sure it never used to do it before i went stage 3, maybee its having a hard life and just wants a re build.

Im going to see Karl in the new year im sure he can tell em what it is as im not going to worry about it just yet, all i want to do is ensure ill be ok for the ring trip next year

Cheers people

AlexF

turbos need back pressure?!?!

Since when?!


Alex

Beach

Yeah i will have to do the comp test to be sure aswell.

Its been rebuilt 13k ago with new 4x4 mahle pistons and rings so id be gutted if it were that.

Cheers for the advice mate