Date: Fri, 1 Mar 2002 08:33:59 -0800
Reply-To: Ben McCafferty <ben@KBMC.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Ben McCafferty <ben@KBMC.NET>
Subject: Re: It's smoking! Help!
In-Reply-To: <F620BzwrO544tuvN8Kr0001ab96@hotmail.com>
Content-type: text/plain; charset="US-ASCII"
Hi Jon,
No, it won't leave you stranded, it would just keep getting worse over time.
If it's bad enough, it will also foul your plugs pretty quickly, and that
could potentially leave you stranded. Think 2-cycle plugs, and you get the
idea.
A compression test wouldn't really diagnose this problem, because it's
measuring compression while the valves are closed, i.e. the valve guides are
not inside the compression chamber. It would indicate bad rings or a burned
valve or worn/pitted valve seats. Those three things would cause blue
smoke, but it would usually be consistent when under acceleration, not when
you let off the gas (though it could be worse when you let off the gas as
well).
If you have bad valve guides, valves, or valve seats, they can all be
remedied by pulling the heads and having them reworked. Find a good
VW-knowledgeable shop, not just any machine shop. If it's rings, you'd also
need to at least do a top-end (pull the cylinders and replace rings, break
glaze in cylinders, lap cylinders into reworked heads, replace cylinders and
heads with new pushrod tubes as needed).
If you do just the heads, you will probably want to lap in the cylinders
again, since they may no longer be perfectly flat on the end that meets the
heads. So if you pull the heads, you may as well do rings at the same time.
While you're going that far, it wouldn't hurt to have endgap on your
crankshaft tested, and if it's out of whack, you may want to do a full
rebuild. This whole job is a lot easier if you just drop the engine, and
you'd be surprised how fast it goes.
Welcome to Pandora's Box.
bmc :)
"Faith will move mountains, but you'd better bring a shovel...."
> From: Jon Joyce <okartguy@HOTMAIL.COM>
> Reply-To: Jon Joyce <okartguy@HOTMAIL.COM>
> Date: Fri, 1 Mar 2002 00:21:05 -0600
> To: vanagon@GERRY.VANAGON.COM
> Subject: Re: It's smoking! Help!
>
>> In my experience, the scene you describe means valve guides are going.
>
> Ben-
>
> What's the best solution if this is indeed the case? Is this a problem that
> will leave me stranded any time soon? The bus still fires right up hot or
> cold, and idles fine. Will a compression test confirm a valve guide problem?
> Thanks for your help-
>
> JJ
>
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