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Re: [Healeys] playing detective

To: PG <bj8mk3@shaw.ca>
Subject: Re: [Healeys] playing detective
From: "Richard Ewald" <richard.ewald@gmail.com>
Date: Thu, 27 Sep 2007 23:35:31 -0700
If you put 150 PSI into a cylinder you will wind up pushing the piston to
bottom dead center.  Pushing the piston to BTC will open one valve,
depending on which way the engine rotates.  ask me how I know this.  An
engine only runs about about 60 PSI at idle, and that is enough to push the
piston down.  even with a large leak in the cylinder there is an excellent
change that your compressor can supply the air faster than the problem can
leak it out.  In this case the engine will still rotate.
I am going to go with there is a problem with the valve train.  Either a
rocker is bound up, valves are mis adjusted, a valve is hung up in the head,
or a pushrod is somehow stuck holding the valve open.

Rick



On 9/27/07, PG <bj8mk3@shaw.ca> wrote:
>
> The quickest way to tell your problem is by doing a leak down test.
>
> There are specialized tools for this purpose but, you can do it without.
>
> Using a pressurized air hose with an adaptor to fit in the sparkplug hole,
> pressurize the cylinder you want to test with about 150 lbs of air.
>
> Because you have no compression in this cylinder, the air will leak
> out:  If
> it leaks out the carburetor or the exhaust pipe, you have a leaky valve
> (intake or exhaust depending upon where the air comes out):  If the air
> leaks out through the rings, you will hear the "hiss" through the oil
> dipstick tube.
>
> A least then, you will know where to look.
>
> Good Luck.
>
> Paul
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