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Old 09-08-2010, 04:55 AM
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Possible leaky valve?

Originally Posted by F-BIRD'88
Use a bathroom scale and a drill press. Check them at 1.75" and 1.70".

stock 85# Z28 #105-115 stock diameter race 125-135#
Back in the Seventies I bought my first adapter in order to pressurize a cylinder so I could replace the valve seals without removing the head.

I realized during the course of that job that it was the best diagnostic tool I had ever had. The first cylinder I pressurized was spewing pressure out of the ex valve/tail pipe, so fast I was worried if it would stay up.

Another cylinder had an intake valve nearly as bad and the carb belched up a puff fuel mixture from the intake. Another cylinder had really weak rings.

All the cylinders had a small leak you could hear but if it's bad there is no mistaking it. I keep a kit on the wall and use it once in a while.
Oh, If anyone does this who has never done it before, I recommend a swivel hose and not a quick coupling. Take no chance of it blowing off. keep fingers away from belts and pulleys
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