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REVTECHRACING.COM
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Discussion Starter #1
my car is a 93 tt with only 45k on it and i get a 2 second puff of smoke at idle during redlights more and more often now. i assume its the valve stems seals since it did it during stock twins and now single turbo. i also get smoke[white] on boost but just a tiny hint of it while at wot[people behind me tell me this]. i did a compression test and that was a result. i just wanna narrow this down to the stem seals before i buy them from the dealer and pay big bucks to get this job done right.
 

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353 Posts
I would also check the turbo. Pull the center section of the turbo from the exhaust housing and look for oil in the exhaust housing and on the exhaust wheel.
 

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Sooooooo JDM
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1,221 Posts
As Sal pointed out, check the turbo first. Valve stem seals typically rear their head at cold startup then cease. The smoke will also be blue for stem seals (oil burning). Did you do the single install? If so, what size hose did you use on the oil return?

Ryan
 

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REVTECHRACING.COM
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2,675 Posts
Discussion Starter #7
not the turbo did it single and twins. boost logic kit ,return line is fine.

yes on start up it will be blueish smoke for 2 seconds then gone. the the same at a redlight light and on boost sometimes.hard to tell color when at wot with girlfriend describing it. if not the seals ,what else. oil/coolant have been changed regularly. ive ignored it for about a yaer now and it seems to be a lil more frequent now then before. plus im a picky bastard.
 

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feeding your habit
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stem seals..... that's it. Rings would be shot and show up on compression test if they were the source.

stem seal... stem seal... steemmmmmmmm seaaaallllllll.....
 

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Boost Junkie
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12,385 Posts
VSS for sure. Had the same problem last spring and replaced mine. No more smokey at first. Now my stock twins are on there way out so I am getting a puff at WOT when the 2nd turbo comes on line.


Steve K.
 

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OCC
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897 Posts
98mkiv said:
stem seals..... that's it. Rings would be shot and show up on compression test if they were the source.

stem seal... stem seal... steemmmmmmmm seaaaallllllll.....
Oil control rings have no bearing on compression numbers.

sushi
 

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feeding your habit
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4,015 Posts
Rings certainly are important to compression. Rings provide the seal around the piston. That is why ring end gap is important. Rings are what make compression my friend.... Bad rings = low compression (as would bad valve seats). Try running your motor without rings.....

The problem this person describes is very typical of age or mileage worn stem seals.
 

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Team 10+ Year Member
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3,510 Posts
What would the issue be if I got some smoking coming off an WOT run.. the car dumps smoke out. I know I need VSS b/c the car puffs at startup and coming off a light too.. but under boost a bit and more so when I lay off having just made boost. Any ideas?
 

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This kiss ain't for you!
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368 Posts
on a turboed car this is difficult to diagnose. but a leak down will tell you if your stem seals are done (puff at startup). Also when you let off from boost is can be the compressor thrust collar that are worn to a bad piston ring (creates vacuum in the chamber when you let off). But on a 40k supra piston rings would be premature I suspect the 2nd turbo is at fault. If you can inspect the inside of you intercooler piping. If there is more than juste a very slight coat of oil (nothing greasy here) then your thrust collar are gone...

But seriously a 93car would need an overhaul if it was mine. Things like those (stem seals, turbos) are essential maintenance for a turboed car.

hope that helps...Dont forget if you have access to a compressor, hook up a leak down tester this one is a life saver ;)

Chris
 

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OCC
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897 Posts
98mkiv said:
Rings certainly are important to compression. Rings provide the seal around the piston. That is why ring end gap is important. Rings are what make compression my friend.... Bad rings = low compression (as would bad valve seats). Try running your motor without rings.....

The problem this person describes is very typical of age or mileage worn stem seals.
Thanks for pointing out that rings are necessary for compression. How many rings does each piston contain? There are two compression rings (#1&2), and a oil control ring (#3). As I said before, the oil control rings have no bearing on compression numbers. =)

sushi
 
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