Date: Sat, 30 Dec 2006 23:26:36 +0000
Reply-To: dhaynes@OPTONLINE.NET
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <dhaynes@OPTONLINE.NET>
Subject: Re: Manifold vacuum specs?-Leak down testing
In-Reply-To: <vanagon%2006123012200936@GERRY.VANAGON.COM>
Content-Type: text/plain; charset=us-ascii
A proper leak down test will tell you all you need to know. After measuring the leak down, wit the engine restrained, you can by pass the tester and directly pressurize the cylinders with shop air and you will be able to hear where the internal leakage is occurring. Remove the airflow meter and coolant pressure cap while doing this. If the air forces coolant out of the expansion tank, then you know you have an internal leak. If you hear air leaking through the crank breather, it is getting past the pistons/rings/some leakage is normal past the ring gaps. If your hear leakage through the intake, you have an intake that is not seating and if through the exhaust, bad exhaust valve.
Poor valve seating is usually the result of worn guides. Loosening the lifters may provide temporary relief but this is not the fix. If the lifters are not noisy, it is unlikely they are a problem unless you excessively high oil pressure or weak valve springs.
Dennis
----- Original Message -----
From: Geza Polony
Date: Saturday, December 30, 2006 12:31 pm
Subject: Manifold vacuum specs?
To: vanagon@GERRY.VANAGON.COM
> Volks--
>
>
> I've been trying to sleuth out yet another prob on my '84 1.9:
> erratic idle,
> compression noise under load, low (er) power on hills, harder
> starting when
> hot. I'm toying with the idea that there's a lifter problem, a valve
> problem, or worse, ie., rings or head gaskets.
>
> Now. I went out and got a vacuum guage and compression tester.
> However, I
> can't find the correct specs for vacuum readings ANYWHERE in the
> Bentley or
> the Haynes manuals. Am I missing something?
>
> Nearest I can find, searching the archives, is that 8 in. is too
> low. Is
> that right? What's the acceptable range?
>
> What else am I looking for in this vacuum test? Just vacuum level?
>
> Is there a way to pinpoint problems with it, or does it just
> tell you
> "there's a problem?"
>
> I want to try backing out the valve adjustment screws to give a
> .06 lash as
> suggested by some of the heavyweights here (and in Bentley) but
> understandit's better to read vacuum and compression before and
> after.
> Thanks to all--
>
> Geza
>
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