All,
Metallurgy 101
I would highly recommend AGAINST wrapping mild steel headers on a street
car. Because the heat is kept in, the working temperature of the header is
raised significantly. At this elevated temperature it doesn't matter
whether you live in an area of high corrosion or not, the steel is at a
temperature where the material begins to break down and oxidise at an
accelerated rate. You'll be lucky if you don't have to replace headers
every year or so.
Aaron
>
>
> ----- Original Message -----
> From: "Neil Penberthy" <npenberthy@yahoo.com>
> To: <spitfires@autox.team.net>
> Sent: 27 March, 2003 11:56
> Subject: Re: Exhaust questions: paste, wrap, needles
>
>
> > Bill mentioned cracked headers:
> >
> > "Joe's comments started me on something of a tangent
> > to this thread. I was wondering what bearing exhaust
> > wraps and coatings might have on the cracking which is
> > a perceived problem with stainless manifolds. Has
> > anyone done any kind of study on this?"
> >
> > Bill
> >
> > My Triumphtune mild steel headers cracked without any
> > wrap or coatings. I think that the movement of the
> > engine on the mounts and the movement of the exhaust
> > system make cracking almost inevitable.
> >
> > Mine lasted around 50,000 miles and were easily fixed
> > by an exhaust shop for $10. I may end up using header
> > wrap as I think the risk of corrision is small here in
> > Texas, and I am still thinking that my misfire might
> > be heat related. Maybe I should find some heat shields
> > for the carbs. I knew I shouldn't have thrown them out
> > !!
> >
> > Neil
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