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Blue Smoke Out Of Exhaust

SECURITY

By SECURITY,
in Engines & Forced Induction

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SECURITY Grand Master

SECURITY

Posted
Posted

well when im on boost i get some blue smoke. on idle and low rev driving its fine.

oil pressure is fine too.

im not sure if its my rings or my valve stem seals.

ive completely ruled out the new turbo as ive checked the cooler pipes etc.

ill be doing a compression test tomorrow to see if its my rings (mind you ive rebuilt the motor with NEW rings).

what should i be looking out for if its my valve stem seals?

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Ryanrb25 Grand Master

Ryanrb25

Posted
Posted (edited)
sorry to ask this question, i am curious how you guys find out that smoke is blowing out of the exhaust while you are driving? especially on boost.

revision mirror dude.

your turbo can still be burning oil without traces in your cooler pipes...the rear seal in your turbo could be gone. say movement in your turbo shaft can be pulling forward under boost so that allows oil to slip out the seal on the exhaust side. hence only on boost. idle the motor and take the oil cap off and feel for excessive blow by.

you cant really 'check' valve stem seals. you only know it was them when you change them and the smoke stops. spent hours on a 4g63 changing the valve stem seals only to find out that it was the turbo seals.

Edited by Ryanrb25
DVS JEZ Grand Master

DVS JEZ

Posted
Posted
orh ok. thanks. i am wondering how to spot the problem if i happen to encounter one.

cheers

do you have a catch can???

also is it plumbed back into the inlet and or turbo ducting?

take off your rockers and check if the breathers are clogged in the rocker cover baffles,

i had similar problem after i built my engine, new turbo everthing, was blowing shit loads of smoke(blue)

found to be cause the breathers were blocked due to old engine having so much blo by..

hope this helps

Jeremy

SECURITY Grand Master

SECURITY

Posted
  • Author
Posted

thanks for the replies guys.

im going to compression test it today, ill take it for a drive and see if its doing it today, its a bit on and off sometimes.

ill check my breather pipe after the drive too.

Space Goat Community Regular

Space Goat

Posted
Posted

any other symptoms??? misfiring... check out your spark plugs too (stupid to say i guess coz you take em out when you comp test anyway) if theyre fouled or very clean

how long since the rebuild

Omurru Veteran

Omurru

Posted
Posted

After my engine was built, it was doing similar things and it came down to 2 of the rings were leaking. They said it was something to do with the type of rings that were used, they either seat properley and you never have a problem or they don't and they leak. They replaced all the rings with new ones and haven't had a problem since.....

DVS JEZ Grand Master

DVS JEZ

Posted
Posted (edited)
i have heard the same thing about the valve stem seals

your having the exact same symptoms as i did,

check your breathers in the rocker covers,

take them out and soak them in kero,then let them dry then put it all back in

Edited by DVS32R
Omurru Veteran

Omurru

Posted
Posted
the rings i used were brand new from nissan. they were placed on the right angles too (i.e. not on the thrust side of the piston).

ah fair enough, I dun have factory ring there something else. Can't think of what there made of off the top of my head....

Abo Bob Grand Master

Abo Bob

Posted
Posted

Yeah valve stem seals going is usually evident by what I would call back off blow by.

I'd be thinking of rear turbo seal possibly. This happened to me recently.

Are you sure it's blue and not black from running rich? (Have to ask. :dry:)

Is it definitely coming OUT of the exhaust? I mean, some oil could be dripping ONTO it from somewhere possibly, although you would probably smell it when idling.

wrxhoon Grand Master

wrxhoon

Posted
Posted

Blue under hard acceleration sounds like rings to me, of course turbo seal will do the same thing, stemseals will smoke downhill of throtle.

Don't forget slightly worn or not bedded in rings won't always show on a compression test because the oil blocks the gap and you could have perfect comp. Actualy a slightly worn engine ( bottom end, not worn valves) could have higher comp due to the fact that you may have carbon on the top of the pistons.

Do a leakdown test , then you will know for sure if you are loosing comp.

SECURITY Grand Master

SECURITY

Posted
  • Author
Posted
Blue under hard acceleration sounds like rings to me, of course turbo seal will do the same thing, stemseals will smoke downhill of throtle.

Don't forget slightly worn or not bedded in rings won't always show on a compression test because the oil blocks the gap and you could have perfect comp. Actualy a slightly worn engine ( bottom end, not worn valves) could have higher comp due to the fact that you may have carbon on the top of the pistons.

Do a leakdown test , then you will know for sure if you are loosing comp.

thanks mate, ill get a leakdown test done.

is there any way to check if its the turbo?

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