Leakdown Numbers Needed

GASKETBOY · #1 (**permalink**) 07-02-2003, 01:32 PM

What should I expect to see for a % on an FE is good condition, and at what % should I get the hoist ready?

The engine in question is a 390, unsure of the internal specifics as far as ring type, end gap, etc. Heads are Edelbrock with less than 5,000 miles. No loss through carb or exhaust - it went past rings.

I ran the test, but the numnbers are at home - just need to know how to interpret the data so I do not make a costly mistake.

Thanks guys,

Jeff

speed220mph · #2 (**permalink**) 07-02-2003, 03:39 PM

If leakage is more than 20%, warm up the hoist. However, if leakdown is between 5 and 10%, you're good.

Sounds like your engine is leaking past the rings, so check it after warming up the engine. Numbers may improve.

About the numbers, if your shop pressure is 100 psi, pressure held in the cylinder should be 10% minum. Hope you get good numbers.



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