Leak down Test



Leak down Test

Postby nawlins-tim » July 6th, 2014, 4:20 pm

Grumpy I totally respect your decision making ability and auto knowledge so I figured I'd start this question with you. I have a new motor I'm building and a had a small "alignment pin" issue when I went to assemble some new heads on a freshly decked 400sbc block. Well I'm about 95% happy with the way the heads going on and I have this slight worry that I may have a leak of some kind. And by the way it's in my nature to think of the worst happening in everything I do.
My question is would a leak down test be worth while on a fresh motor that has not been started or broken in. I know I can physically do the test, but would the un-broken in ring be able to hold enough air preasure to tell me if my head gasket is in good shape. I would like to know now , before the engine is in the car, to find out IF in fact my head gasket has a good seal. And if you recommend this type of test, how much air preasure would you use? Thanks, Tim
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Re: Leak down Test

Postby grumpyvette » July 6th, 2014, 6:22 pm

I personally would wait until the rings seat after running the engine for at least 3 hours , and Id use 100psi- 110 psi for testing,and have EACH of the cylinders tested at TDC, so having a degree wheel or at least timing tape on the damper helps
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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