<div dir="auto">I have had exactly the same results as Bob, as in "no noticeable change in temperature" despite those mods.<div dir="auto"><br></div><div dir="auto">M</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon., Sep. 14, 2020, 12:21 p.m. Bob Spidell, <<a href="mailto:bspidell@comcast.net">bspidell@comcast.net</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
  
    
  
  <div>
    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>On 9/14/2020 7:56 AM, Michael Oritt
      wrote:<br>
    </div>
    <blockquote type="cite">
      
      <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" target="_blank" rel="noreferrer">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_-1626287184057819499m_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" rel="noreferrer noreferrer" target="_blank">healeys@autox.team.net</a>><br>
                <b>To: </b><a href="mailto:healeys@autox.team.net" rel="noreferrer noreferrer" target="_blank">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_-1626287184057819499m_5144250852966861597ydpe32942ddyahoo_quoted_0886130810">
                    <div>
                      <div> On Sunday, September 13, 2020, 3:38:08 PM
                        PDT, Charles Schott via Healeys <a href="mailto:healeys@autox.team.net" rel="noreferrer noreferrer" target="_blank"><healeys@autox.team.net></a>
                        wrote: </div>
                      <div><br>
                      </div>
                      <div><br>
                      </div>
                      <div>
                        <div id="m_-1626287184057819499m_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>
              </div>
            </div>
          </div>
        </blockquote>
      </div>
    </blockquote>
    <br>
  </div>

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