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Yeah, I've heard that too (usually from the 'hot rod guys'). I
wrapped my BJ8's downpipes about 8yrs/40K or so miles ago, and when
I rebuilt the engine 3 years ago I checked them; no evidence of any
degradation.<br>
<br>
My thinking: Rust is, of course, oxidation. Water does not rust
metal, it facilitates oxidation by providing a medium for electron
transfer between the oxygen in the air and the iron in steel.
Manifolds, downpipes and headers get hot enough that the water in
the exhaust gasses stays vaporized (until shutdown). It cools and
pools in the pipes and mufflers, which rust from the inside out.
What's unclear to me is how wrap, or ceramic coating, which should
theoretically keep more heat in the system affects the steel. I
would expect some embrittlement from the heat cycling, but haven't
seen it (yet). <br>
<br>
FWIW, I had my exhaust manifold ceramic coated (Jet Hot) and
downpipes wrapped, and didn't notice much, if any cooler running (I
was disappointed). The side vents seem like they would help but,
curiously, my BJ8 and BN2/100M behave exactly the same WRT engine
temps. I expected the louvered bonnet to help prevent overheating,
esp. at idle but ... nope.<br>
<br>
Bob<br>
<br>
<br>
<div class="moz-cite-prefix">On 9/14/2020 7:56 AM, Michael Oritt
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAPTa0B5Wa-h8JK1qqgs9OD6MPWZOFMCWQAW69dWUyfczcM8=LQ@mail.gmail.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
<div dir="auto">Common wisdom isthatexhaust wrapped to rusting
out. it took 15 years to happen on my car and I am not
convinced even now that the wrap promoted or hastened the
process.
<div dir="auto"><br>
</div>
<div dir="auto">Best--Michael Oritt </div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Mon, Sep 14, 2020, 10:16 AM
Charles Schott via Healeys <<a
href="mailto:healeys@autox.team.net" moz-do-not-send="true">healeys@autox.team.net</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>
<div style="font-family:times new roman,new
york,times,serif;font-size:12pt;color:#000000">
<div>Bob,</div>
<div><br>
</div>
<div>I did wrap the headers but I'm a belt and suspenders
type of guy. Never intended it to be that much work, but
once I started, I wasn't going to quit on it. I'm also
going to install the triangular vents into the front
wings which should help expel the heat. And I built a
false floor on the driver's side to provide an air space
that will act as an insulator. It gets hot in Florida.</div>
<div><br>
</div>
<div>Regards,</div>
<div><br>
</div>
<div>Charlie</div>
<div><br>
</div>
<hr id="m_5144250852966861597zwchr">
<div
style="color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt"><b>From:
</b>"Bob Spidell via Healeys" <<a
href="mailto:healeys@autox.team.net" target="_blank"
rel="noreferrer" moz-do-not-send="true">healeys@autox.team.net</a>><br>
<b>To: </b><a href="mailto:healeys@autox.team.net"
target="_blank" rel="noreferrer"
moz-do-not-send="true">healeys@autox.team.net</a><br>
<b>Sent: </b>Sunday, September 13, 2020 11:31:10 PM<br>
<b>Subject: </b>Re: [Healeys] [Healeys) 100-4 Heat
Shield with Headers<br>
<div><br>
</div>
Well done, but I gotta ask, why not just wrap the
headers?<br>
<br>
<br>
<div>On 9/13/2020 8:42 PM, Ray Juncal via Healeys wrote:<br>
</div>
<blockquote>
<div style="font-family:Helvetica
Neue,Helvetica,Arial,sans-serif;font-size:16px">
<div dir="ltr">Wow, you had fun making that. Nice
work.<br>
</div>
<div><br>
</div>
</div>
<div
id="m_5144250852966861597ydpe32942ddyahoo_quoted_0886130810">
<div style="font-family:'Helvetica
Neue',Helvetica,Arial,sans-serif;font-size:13px;color:#26282a">
<div> On Sunday, September 13, 2020, 3:38:08 PM
PDT, Charles Schott via Healeys <a
href="mailto:healeys@autox.team.net"
target="_blank" rel="noreferrer"
moz-do-not-send="true"><healeys@autox.team.net></a>
wrote: </div>
<div><br>
</div>
<div><br>
</div>
<div>
<div
id="m_5144250852966861597ydpe32942ddyiv5409415901">
<div>
<div style="font-family:times new roman,new
york,times,serif;font-size:12pt;color:#000000">
<div>After one more modification, the
fifth one, to eliminate interference
with the vacuum hose fitting, I can
continue with mounting the carbs. Some,
including me, might say it's been over
engineered.</div>
<div><br clear="none">
</div>
<div>Regards,</div>
<div><br clear="none">
</div>
<div>Charlie</div>
<br>
</div>
</div>
</div>
</div>
</div>
</div>
</blockquote>
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</blockquote>
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