Date: Tue, 2 Nov 2010 09:25:44 -0700
Reply-To: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Subject: Re: A response from Prestone about Stainless Steel Pipes
In-Reply-To: <BF46BD5D-D7CF-464E-93E2-7721FD3E6931@shaw.ca>
Content-Type: text/plain; charset=ISO-8859-1
Hey Al, you'd think somebody would know which alloy blend the engines are
made of . Failing that, do you want me to chop a piece off the old 2.1
block I have and send it over?
Jake
On Tue, Nov 2, 2010 at 9:05 AM, Alistair Bell <albell@shaw.ca> wrote:
> Hey, I don't take it as a personal attack, but feel free to knock me
> down a peg or two if I start spouting more Feynman or Fermi quotes :)
>
> The engine alloy is the question. I didn't have a bit lying around to
> use in test. I am thinking it has at least Silicon in the mix,
> perhaps Mg too? This is pure speculation, but the alloy may have been
> chosen for reasons other than corrosion resistance. You notice how
> bad some engine and tranny exteriors look?
>
> What I have concluded after all the discussion about this topic, and
> my wee experiment, is:
>
> 1. its an undeniable fact that aluminium is much more of an active
> metal than any type of stainless.
> 2. if the metals are electrically connected and share the same
> electrolyte, then dissimilar metal corrosion will occur, with the
> aluminium being the anode and oxidised.
> 3. the anti corrosion additives in modern coolants - and I used an
> OAT based (ie Dexcool or "long life" type) - will prevent the
> corrosion on the aluminium.
> 4. the coolant in our vans is, on average, not changed often enough.
>
> The whole subject of dissimilar metal corrosion in a complicated set
> up such as the vanagon cooling system is full of unknowns and is ripe
> for fantasy ideas.
>
> 1. what is happening when you get corrosion under an O-ring or
> gasket? Is it a stagnant area where the coolant is depleted of its
> anti corrosion additives? Or, (and this is really wild speculation),
> does the carbon black filler in rubber O-rings act as the noble
> metal? Carbon is close to the top, if not at the top, of most list of
> noble metals.
> 2. does the anoxic environment of the system cause any stainless
> steel present to change into its active form (loss of protective
> oxide layer). If so, this might be an advantage, lessening the
> galvanic differences between stainless and aluminium.
>
> I will take pics of the metal samples today, and I will post on my
> blog as well as the previously mentioned samba blog.
>
> Oh one more thing.... I can understand how vendors of stainless pipes
> might feel a little uneasy with this discussion. Ken, you are the
> first vendor that actually seems to care and do some research rather
> than reflexively attack or dismiss the whole idea. Good on you Ken, I
> mean it.
>
> alistair
> '86 syncro 7 passenger
> '82 westy, diesel converted to gas in '94
> http://shufti.wordpress.com
>
>
> On 2-Nov-10, at 8:31 AM, Ken Wilford wrote:
>
> Alistair, I am happy you are doing this experiment. Just so you know
> all the the stainless lines that I have sold and seen are 304
> stainless. So your test should be good. Not sure what alloy the
> Vanagon engine case is though.
>
> PS I didn't know you were doing this so please don't take my post as
> some type of personal attack on you. I respect folks who are willing
> to test things. Just not folks who only speculate.
>
> --
> Thanks,
> Ken Wilford
> John 3:16
> www.vanagain.com
> Phone: 856-327-4936
> Fax: 856-327-2242
>
--
Jake
1984 Vanagon GL 1.9 WBX 'The Grey Van'
1986 Westy Weekender/2.5 SOHC Suby 'Dixie'
Crescent Beach, BC
www.thebassspa.com
www.crescentbeachguitar.com
http://subyjake.googlepages.com/mydixiedarlin%27
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