Leak Down Results
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?
Pouria Savadkouei
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
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
Thread Starter
Launching!
Joined: Mar 2009
Posts: 203
Likes: 0
From: Chesterfield, VA
R1, Not quite sure if you're calling me an idiot or trying to help but thanks for your input all the same.
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.
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.
Banned
Joined: Oct 2009
Posts: 992
Likes: 1
A stock factory built engine is going to be from 5-10% REALISTICLY.
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.
A stock factory built engine is going to be from 5-10% REALISTICLY.
Thread Starter
Launching!
Joined: Mar 2009
Posts: 203
Likes: 0
From: Chesterfield, VA
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.
Banned
Joined: Oct 2009
Posts: 992
Likes: 1
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.
If those numbers are good your pistons and cylinders are in excellent condition.
Thread Starter
Launching!
Joined: Mar 2009
Posts: 203
Likes: 0
From: Chesterfield, VA
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.
If those numbers are good your pistons and cylinders are in excellent condition.
Banned
Joined: Oct 2009
Posts: 992
Likes: 1
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
Sorry but i still don't beileve your test results. Are you sure Elvis didn't test it? LOL
Thread Starter
Launching!
Joined: Mar 2009
Posts: 203
Likes: 0
From: Chesterfield, VA
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
Sorry but i still don't beileve your test results. Are you sure Elvis didn't test it? LOL
Thanks for all the input folks. I am learning to filter through all the varying degrees of relevance.
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.
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; Feb 25, 2010 at 12:14 AM.