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Leak Down Results

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Old 02-12-2010, 12:54 PM
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Default Leak Down Results

I was a little worried going in. 43K miles on 01 WS6. All cylinders were within 2%. Suweeet.

Don't burst my bubble if this is no big deal, OK?
Old 02-12-2010, 01:07 PM
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POP.. thats normal. lol
Old 02-12-2010, 02:52 PM
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Within 15% is good, if yours are within 2% thats a good *** set of rings and cylinder wall seal.
Old 02-12-2010, 03:03 PM
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All cylinders showed 2% or less leak down, or all cylinders were within 2% of each others' leakdowns?
Old 02-12-2010, 04:48 PM
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All cylinders showed 2% or less leakdown. 5 cylinders were 1%.
Old 02-12-2010, 05:24 PM
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Damn that is typical of a hand built race motor not a mass produced factory piece....
Old 02-13-2010, 03:58 AM
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Originally Posted by danbrazda
Don't burst my bubble if this is no big deal, OK?


sorry I had to...

but 43k miles is like brand new for one of these engines, especially if it is all stock...good deal.
Old 02-13-2010, 01:10 PM
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Good to know you have a solid foundation.....not to open a can of worms, but have you pulled the intake?
Old 02-22-2010, 07:03 PM
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Originally Posted by SOMbitch
Damn that is typical of a hand built race motor not a mass produced factory piece....
+1

I don't know who leak-down tested your motor, but I am 99% sure you were lied to. A stock motor is never going to leak-down that low. I guess you keep listening to people who don't know about these cars
Old 02-23-2010, 07:12 AM
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Originally Posted by AFASTYZFR1
+1

I don't know who leak-down tested your motor, but I am 99% sure you were lied to. A stock motor is never going to leak-down that low. I guess you keep listening to people who don't know about these cars
There is a better chance that I misunderstood what I was told rather than I was "lied to". I'll call and ask better questions.

R1, Not quite sure if you're calling me an idiot or trying to help but thanks for your input all the same.
Old 02-23-2010, 07:25 AM
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That's pretty low, I've never heard of a stock motor that low, they're usually higher then that.

I'd believe that all the cyl's were within 2%, but 2% seems low to me. But hey, if it's that good, go with it!

fwiw, my race motor's about 12 to 15%, but that's gapped for 400hp of nitrous, so it's normal.
Old 02-23-2010, 10:09 AM
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Originally Posted by danbrazda
I was a little worried going in. 43K miles on 01 WS6. All cylinders were within 2%. Suweeet.

Don't burst my bubble if this is no big deal, OK?
Yeah i have nice bridge in Jersey for sale...........I'm not trying to upset you but there is NOWAY you have 2% or less leakage. I suspect one of two possiblites,either they never tested it and are just blowing smoke(most shops VERY rarely do leak tests and just flat out lie about results) OR they don't understand how to use the tester properly.

A stock factory built engine is going to be from 5-10% REALISTICLY.
Old 02-23-2010, 10:38 AM
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Originally Posted by O2Form
Yeah i have nice bridge in Jersey for sale...........I'm not trying to upset you but there is NOWAY you have 2% or less leakage. I suspect one of two possiblites,either they never tested it and are just blowing smoke(most shops VERY rarely do leak tests and just flat out lie about results) OR they don't understand how to use the tester properly.

A stock factory built engine is going to be from 5-10% REALISTICLY.
I bet they didn't even test it. I'm not trying to insult you Dan, but I told you I would leakdown your car if you were worried. Instead I'm sure you paid more and got impossible results which suggests they didn't even test it and just told you a number you would want to hear.
Old 02-23-2010, 11:12 AM
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Originally Posted by AFASTYZFR1
I bet they didn't even test it. I'm not trying to insult you Dan, but I told you I would leakdown your car if you were worried. Instead I'm sure you paid more and got impossible results which suggests they didn't even test it and just told you a number you would want to hear.
I stood and watched while they tested it. They were very surprised the numbers were as tight as they were. Maybe they were doing something wrong? Whatever. You sound very confident and I don't doubt your experience with these cars but you're just guessing when you say things like "they lied" and "they never tested it". Based on the overall feedback from this thread I will assume all cylinders are within 1-2% of each other and that is not the baseline for the overall leakdown of the engine.
Old 02-23-2010, 12:29 PM
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If you watched them then what is the issue? Did they set everything up properly? There are alot of things you could do wrong. You need to put exactly 100psi into the leak down tester with the cylinders at bdc. Then if you are real tricky you test um at TDC too.

If those numbers are good your pistons and cylinders are in excellent condition.
Old 02-23-2010, 12:54 PM
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Originally Posted by O2Form
If you watched them then what is the issue? Did they set everything up properly? There are alot of things you could do wrong. You need to put exactly 100psi into the leak down tester with the cylinders at bdc. Then if you are real tricky you test um at TDC too.

If those numbers are good your pistons and cylinders are in excellent condition.
No problems here. Just trying to reply to those who called BS on the thread. As I said, I am walking away from the experience confident that my bottom end is in decent shape-period.
Old 02-23-2010, 03:21 PM
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Bottom end? No .....your pistons rings seal very well to the cylinder walls and the valves seal well. Thats what a leak down test indicates. Bottom end = crank and rod, main bearings and crank end play and timing chain slack. Need to pull it apart to check the bottom end.

Sorry but i still don't beileve your test results. Are you sure Elvis didn't test it? LOL
Old 02-23-2010, 03:45 PM
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Originally Posted by O2Form
Bottom end? No .....your pistons rings seal very well to the cylinder walls and the valves seal well. Thats what a leak down test indicates. Bottom end = crank and rod, main bearings and crank end play and timing chain slack. Need to pull it apart to check the bottom end.

Sorry but i still don't beileve your test results. Are you sure Elvis didn't test it? LOL
Where's that "beating a dead horse" emoticon when I need it? I think it has been well established that many feel I was given bad info. What started out as a relatively light-hearted thread has now reached the point of diminishing returns.

Thanks for all the input folks. I am learning to filter through all the varying degrees of relevance.
Old 02-23-2010, 04:01 PM
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I'm not buying what they were selling you.
Old 02-25-2010, 12:09 AM
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tonight i installed my LS6 valve springs and to fill the cylinders with air to hold up the valves i use a leak down tester, here are the results.

starting at drivers side front and working around to the passenger side front, I used 75 psi in and did not rotate any of the cyl to BDC or at all for that matter all test was done at what ever location in the bore the piston happened to be at, all test was done with no rockers installed so the valves was all closed.
75 input pressure.
\
62 driver side front
74
60
65 driver side rear
73 passenger side rear
73
73
72 passenger side front

ok so as you see 1 cyl was 75 in 74 out and a bunch was 73 so indeed 2% or less is possible, miles on the motor are unknown, but it runs like a champ and only smokes after a hard pull and i let it decelerate hard and then get back in it. the most deposited spark plug was the one from the 74 cylinder which was the best leak down number lol, i figure the oil was the valve seals and yes i replaced them to. any way it seems my best is 2% or better and my worse is 15% so there is a 12% variance between best and worse. The car goes on the dyno in 2 weeks and the boost gets turned up so the way i see it at least 3 of my cylinders are already loose enough for higher boost hahah.

Last edited by lavoy; 02-25-2010 at 12:14 AM.


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