Date: Thu, 22 Oct 2009 18:43:53 -0400
Reply-To: Mike <mbucchino@CHARTER.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mike <mbucchino@CHARTER.NET>
Subject: Re: 1.9 Head replacement (was lifter collapse / smog issue)
Content-Type: text/plain; charset="iso-8859-1"
NO silicone sealant is rated for DIRECT and CONTINUOUS exposure to the extremely high temps and pressures of an exhaust system, even Ultra Copper RTV. It's rated for 700 degrees F max, and EGT's (exhaust gas temps) can sometimes reach 1500 degrees F, so the reality is that it just won't hold up for the long run. I don't care what it says on the package. Don't forget, they want to sell you something that's a cheaper magic cure to your problems.
If your exhaust flanges are that damaged, you need new pipes, along with your new gaskets. However, slightly-scratched up or distorted flanges can be hammered and filed back to perfectly flat for better sealing.
Mike B.
----- Original Message -----
From: Dennis Haynes
To: vanagon@GERRY.VANAGON.COM
Sent: Thursday, October 22, 2009 6:02 PM
Subject: Re: 1.9 Head replacement (was lifter collapse / smog issue)
Silicone anything on exhaust gaskets does not add any sealing value except
maybe to foul the O2 sensor and catalyst.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
craig cowan
Sent: Thursday, October 22, 2009 4:12 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 1.9 Head replacement (was lifter collapse / smog issue)
Any exhaust gasket that comes off needs to be replaced. You're unlikely to
get a good seal putting a used gasket back on, as they compress to fit. I
also tend to replace every coolant or otherwise gasket that I take off, as I
tend to feel that most are a "one time" use type of thing (as they compress
to fit).
If you've never taken a head off before, come ready with a pry bar and
rubber mallet. They don't always put up a fight, but when they do, you want
to be armed. Benny-Boy has a great video on how to remove a head (properly),
you might want to check out his site.
Keep everything clean, the cleaner the better. It's always good to have
clear access to what your doing, and clean it up BEFORE you remove the head,
otherwise stuff will just fall in as you take the head off.
Junk in an engine= bad.
There's some people that believe you cannot remove the head even once
without having to replace the studs, which are of the stretch variety. It's
a reasonable claim, I've just never felt the need to replace them (if
they're in good shape).
When you get the heads off and you want to clean up the insides of the
combustion chamber (on the head) or the valves themselves, Regular H20
(Water, Hydrogen Hydroxide, Etc) will make carbon dissolve if you just let
it soak for a bit. I learned that if you soak a valve covered in carbon in a
glass of water, you'll be left with a clean valve.
Upon reassembly remember to wet your gaskets. Coolant gaskets get wet down
with some coolant, Oil gaskets with some oil, and Exhaust gaskets can go on
dry (though I like using Permetex Ultra Copper on both sides).
Good luck, have fun.
-Craig
'85GL turned WESTY
BOSTIG in the back
On Thu, Oct 22, 2009 at 3:51 PM, Leonard Anthony
<whitewatering@gmail.com>wrote:
> The lifter was fine. The valve adjuster tip (intake, cyl 1) sheared off so
> I
> replaced it and adjusted the valves.
> The exhaust valves on 3 & 4 failed the leak down test. This engine is a
> Canadian VW Reman with ~ 15,000 mi.
> Cyl 1&2 tested OK, German head. Cyl 3&4, bad valves, on AMC head. So this
> is
> probably a quality issue with the valves on the AMC heads, as I've read
all
> about it. Even though the engine has very low miles it had been replaced
in
> '02, seemingly a very bad year for AMC heads, from what I have read from
> the
> archives & elsewhere.
>
> Before I pull the head off, I thought I would ask (those on the list who
> have replaced heads before) if there are any shortcuts, hints or do's &
> don'ts not covered in the Bentley on head replacement. I don't want to
> touch
> the good side. Will 1 head gasket set be enough or will I also need
exhaust
> / coolant etc. gaskets for the good side? The engine does not currently
> leak
> anything, the water jacket is fine.
>
> Also, I'm wondering how to tell if the heads are 1.9 or 2.1, as it sounds
> like they should not be co-mingled on an engine. What about co-mingling
> German & Spanish heads, as was done on my VW rebuild? I do have an extra
> German 1.9 head but until I pull them off the engine(s) I won't know which
> one will be better to use.
>
>
> Thanks,
> Leonard
>
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