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Re: [oletrucks] leak-down compression test

To: "Rob J." <a70ragtop@hotmail.com>
Subject: Re: [oletrucks] leak-down compression test
From: "A.B." <bigfred@unm.edu>
Date: Wed, 23 Jan 2002 13:39:47 -0700 (MST)
I can't see why that wouldn't work, other then the leak down not telling
you if your valves are closing all the way.


On Wed, 23 Jan 2002, Rob J. wrote:

> Would it be possible to simply loosen the rocker arm assembly, removing the
> pressure on the valve springs?  That would eliminate having to individually
> put all pistons at TDC in order to ensure the valves are closed.  Seems that
> percentage drop should not matter whether the piston is at TDC, or bottom or
> middle.  Just a thought.
>
> Rob
>
> My Zen Moment for the Day:  Don't be irreplaceable.  If you can't be
> replaced, you can't be promoted.
>
> ----- Original Message -----
> From: "A.B." <bigfred@unm.edu>
> To: "Dana Muise" <dana@spazzco.com>
> Cc: <oletrucks@autox.team.net>
> Sent: Wednesday, January 23, 2002 12:04 PM
> Subject: Re: [oletrucks] leak-down compression test
>
>
> > On a leak down the PSI isnt' really all that important, you are really
> > just looking for the percentage of leakage, ie, if you put in say 50 psi
> > (w/piston at TDC so it doesn't turn the motor and the valves stay shut),
> > and lose 2.5 psi you are losing 5%, 100 psi is the easiest, I use that on
> > modern motor cycle engines, but I dont' know if that is a safe pressure
> > for these older motors. I assume it should be fine.
> > -alfie
> >
> >
> > On Wed, 23 Jan 2002, Dana Muise wrote:
> >
> > > Hey truckers
> > > I did a compression check on my old 235 last week and all 6 cylinders
> came in
> > > about 10 lbs below the minimum. The manual said to put a little oil into
> the
> > > cylinders and try it again. They all checked great after that. People
> are
> > > telling me this indicated worn rings. Does any one have any theory on
> this?
> > >
> > > I'm going to perform a leak-down check this week-end. I'm told you have
> to
> > > listen at the tail pipe or intake for hissing (bad valves) or oil
> breather for
> > > bad rings. Is this right? It doesn't seem very accurate. Does anyone
> know what
> > > the PSI range is for this check?
> > > Thanks for you help!
> > > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
> > oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959

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