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Saturday Night Racer >> RACE TECH >> Leak down numbers
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Message started by 3racer on 01/16/10 at 8:40pm

Title: Leak down numbers
Post by 3racer on 01/16/10 at 8:40pm

What should a race motor leak down %'s be?

Thanks for any help.

Title: Re: Leak down numbers
Post by Nick on 01/17/10 at 3:41pm

0% leak for racing applications lol

Title: Re: Leak down numbers
Post by miniguru27 on 01/17/10 at 10:27pm

I would say no more than 5% total.Anything more i would be doing a valve job to start with.JMO
Mike Weigel

Title: Re: Leak down numbers
Post by slidinbmw on 01/19/10 at 9:06am

I see 20% all the time on new crate motors. Just make sure you are even between cylinders. The quality of your gauge matters too. You will obviously see higher numbers on a cold engine.

Title: Re: Leak down numbers
Post by 3racer on 01/19/10 at 1:24pm

Thanks for the help. Turns out one of the holes was leaking pretty bad. Upwards of 30%. Rebuild time. Thanks again.

Title: Re: Leak down numbers
Post by imracin68j on 01/20/10 at 7:58pm

If you're not seeing smoke out of the breathers I wouldn't worry about it. Some motors are loose at cooler temps. Throw a compression guage and see if you see a big difference between the cylinders.

Title: Re: Leak down numbers
Post by mudslinger47 on 01/22/10 at 9:45pm

Depends on your rings too, gapless or standard.

Duane