Blowing blue smoke on decel...
07-15-2013, 09:23 AM
#1
Blowing blue smoke on decel... Hey guys,
I have a 2002 LS1 installed in my Porsche 944 track car. Mods to the LS1 are Kooks long tubes, EPS cam, FAST92/92 and a matching tune.
I'm burning oil and blowing blue smoke on decel. I plan on doing a compression and leakdown test this week.
What are the odds that it's the valve guide seals vs rings?
If it's rings, where's the best place to source a LS2/3 short block?
TIA!
I have a 2002 LS1 installed in my Porsche 944 track car. Mods to the LS1 are Kooks long tubes, EPS cam, FAST92/92 and a matching tune.
I'm burning oil and blowing blue smoke on decel. I plan on doing a compression and leakdown test this week.
What are the odds that it's the valve guide seals vs rings?
If it's rings, where's the best place to source a LS2/3 short block?
TIA!
07-15-2013, 09:33 AM
#2
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Mine did that exact thing. Ran great but only smoked at the end of the 1/4 mile when I lifted.....#7 cyl was down 40psi, pulled heads and found a broken piston.....Now I'm in the middle of a 415 LS3 build
Do you have a catch can? It could be pulling oil on decel
Do you have a catch can? It could be pulling oil on decel
07-15-2013, 03:40 PM
#4
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Mine does it as well. Sounds like youre going to answer your own question, but of course if compression is fine you know its valve seals, if comp is down you know its rings.
07-15-2013, 03:57 PM
#5
I'm trying to prepare for the worst, where's a good place to get a short block if I need it?
I've called Texas Performance and they're 3-5 weeks out, plus time for freight. At that point I'd miss the rest of the season.
Anywhere else have crate LS2-3 short blocks or a reputable engine builder that could get one out quickly?
I've called Texas Performance and they're 3-5 weeks out, plus time for freight. At that point I'd miss the rest of the season.
Anywhere else have crate LS2-3 short blocks or a reputable engine builder that could get one out quickly?
07-15-2013, 05:36 PM
#6
I had the same issue and it was valve stem seals...
I used TMS (http://thompsonmotorsports.net) for an LS1 short block just last year and have nothing but great things to say about them.
I used TMS (http://thompsonmotorsports.net) for an LS1 short block just last year and have nothing but great things to say about them.
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07-16-2013, 07:04 AM
#8
Good Luck... I will go ahead and recommend the 2nd design seals if you end up replacing them. (It's actually so cheap it's worth just doing it regardless).
You don't want to change them again... trust me.
https://ls1tech.com/forums/generatio...al-issues.html
You don't want to change them again... trust me.
https://ls1tech.com/forums/generatio...al-issues.html
07-16-2013, 11:42 AM
#10
You can get them at the parts store (Autozone and Carquest had them).. just have to pay attention to which part they offer you.
Do you have dual springs? That might be the only hang up...(Someone out there hopefully knows for sure) but I think the 1 piece seals won't fit under most dual springs.
Do you have dual springs? That might be the only hang up...(Someone out there hopefully knows for sure) but I think the 1 piece seals won't fit under most dual springs.
07-16-2013, 12:12 PM
#12
You should be ok... I'm looking now but this appears to be the felpro part ss71039
http://www.ws6project.com/user_stor/...elpro-ss71039/
http://www.ws6project.com/user_stor/...elpro-ss71039/
Within 5% on each cylinder too. Looking like it's the valve stem seals, so I'll have them replaced and go from there... 
07-28-2013, 01:06 PM
#15
Well, valve stem seals are replaced, however we found play in the exhaust valve guides.
The car isn't smoking as badly, but it's 5% down on power on the dyno. It was making 400rwhp, now it's making 380rwhp.
Looks like it's time to replace the heads, as it's not worth me pulling the heads (241's) off to get them rebuilt when I can put on a set of 243's instead.
The car isn't smoking as badly, but it's 5% down on power on the dyno. It was making 400rwhp, now it's making 380rwhp.
Looks like it's time to replace the heads, as it's not worth me pulling the heads (241's) off to get them rebuilt when I can put on a set of 243's instead.
07-28-2013, 11:13 PM
#18
Dynoed right away. The smoke got better as more dyno runs went on, but the fact remains that I'm 20rwhp and 20ft lbs down vs earlier this past spring. Something is causing the power loss and the leakdowns and compression test are good, so it's not the bottom end...
