When to freshen the motor?

[sho305]

I wondered if you guys have any easy ways you check unknown motors to know when it needs freshening? I know if the compression has a change between cylinders over maybe 5-10psi, but how else? My old inline for example, is within 2psi...how should I find out before it blows?

[Jay Smith]

A Leakdown test is a good test as to the condition of the ring-bore combo. A GOOD sealing motor is 4 to 8% leakage. Anything more and I suggest its time to re ring. BTW Balzy makes a GREAT LEAKDOWN tester at a real bargin price , contact him !

[sho305]

Ok, I checked it out and he has a nice tool there....http://www.fortunecity.com/olympia/montana/513/id44.htm

Leakdown:
4-8%? Anyone have other reads on this % like for a mod motor, a stock motor, an old inline like mine:), one about ready to blow? Others say 15%, just wondering....have to get one of those, could use it on lots of things.

Nice site there Jay Smith....suppose you are going to tell me that fine lady does not deliver all of your parts to customers....:) Some very nice parts you make.