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    That thought crossed my mind. I use silicone grease to lube oil
    filter gaskets, and putting silicone dielectric grease in our
    ancient electrical connectors--my dad's Model As used the same
    type--seems to help prevent some of the Lucas gremlins. I use a
    silicone 'oil' where light lubrication is needed and dirt and dust
    can build up (speedo cables and Bendix gears on starters come to
    mind).<br>
    <br>
    I'm taking the '50 to 75' years 'spec' with a grain of sodium
    chloride; cars of that era were designed and built to last for only
    a few years before being traded-in or scrapped, but my BJ8 has over
    205K miles and is going strong (but shows her age).<br>
    <br>
    So, Alan, what did you decide?<br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 2/22/2021 7:00 AM, Michael Oritt
      wrote:<br>
    </div>
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cite="mid:CAPTa0B6uwy5rv34G8UaZ3+ref_d8zMVb3651iwTXu0N_8UaqgQ@mail.gmail.com">
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        <div class="gmail_default" style=""><span
            style="color:rgb(51,51,255)">Bob wrote:  </span><font
            color="#0000ff">"I'm surprised they lasted this long--if
            they did--it's a pretty harsh environment for rubber. As a
            rule, I don't lubricate any rubber parts with a
            petroleum-based grease or oil; silicone is supposedly less
            antagonistic to rubber."</font></div>
        <div class="gmail_default" style=""><font color="#0000ff">--------------------------------------------</font></div>
        <div class="gmail_default" style=""><font color="#0000ff">50 to
            75 years is a pretty good replacement cycle.  </font></div>
        <div class="gmail_default" style=""><font color="#0000ff">Maybe
            we should now be searching for silicon-based motor oils?</font></div>
        <div class="gmail_default" style=""><font color="#0000ff"><br>
          </font></div>
        <div class="gmail_default" style=""><font color="#0000ff">Best--Michael
            Oritt</font></div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">On Sun, Feb 21, 2021 at 3:47
          PM Bob Spidell <<a href="mailto:bspidell@comcast.net"
            moz-do-not-send="true">bspidell@comcast.net</a>> wrote:<br>
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          0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
          <div> re: "... I'm wondering if these things have a definite
            life which originals are now reaching."<br>
            <br>
            I'm surprised they lasted this long--if they did--it's a
            pretty harsh environment for rubber. As a rule, I don't
            lubricate any rubber parts with a petroleum-based grease or
            oil; silicone is supposedly less antagonistic to rubber.<br>
            <br>
            Side note: The original car gear for the 4-cyls, with the
            metal 'slinger' plate are NLA. A Moss blurb advises
            transferring an original plate to one of their newer
            replacements; anyone tried this (it requires rivets)?<br>
            <br>
            <br>
            <div>On 2/21/2021 12:37 PM, Michael Salter via Healeys
              wrote:<br>
            </div>
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                <div class="gmail_default"
                  style="font-family:"comic sans
                  ms",sans-serif;font-size:small">Until fairly
                  recent years I had never experienced the breaking up
                  of the rubber slipper on timing chain tensioners but
                  the engine I recently disassembled had one that was
                  completely destroyed. Apparently this was the original
                  tensioner so I'm wondering if these things have a
                  definite life which originals are now reaching.</div>
                <div class="gmail_default"
                  style="font-family:"comic sans
                  ms",sans-serif;font-size:small"><br>
                </div>
                <div class="gmail_default"
                  style="font-family:"comic sans
                  ms",sans-serif;font-size:small">M<br>
                </div>
              </div>
              <br>
              <div class="gmail_quote">
                <div dir="ltr" class="gmail_attr">On Sun, Feb 21, 2021
                  at 2:27 PM Michael Oritt via Healeys <<a
                    href="mailto:healeys@autox.team.net" target="_blank"
                    moz-do-not-send="true">healeys@autox.team.net</a>>
                  wrote:<br>
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                  0px 0.8ex;border-left:1px solid
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                  <div dir="ltr">
                    <div class="gmail_default"
                      style="color:rgb(51,51,255)">In the string about
                      rubber valve seal shrouds Bob Spidell said:  "By
                      no means let crumbling rubber parts see the inside
                      of an engine."</div>
                    <div class="gmail_default"
                      style="color:rgb(51,51,255)"><br>
                    </div>
                    <div class="gmail_default"
                      style="color:rgb(51,51,255)">About a year back I
                      dropped the oil pan on my 100 to replace the oil
                      pump and found numerous chunks of what seemed like
                      very hard black plastic distributed throughout the
                      sump.  This was a head scratcher as I knew there
                      could be no plastic in the engine's interior yet
                      there it was.  After thinking about it further I
                      decided that it could only have been the remains
                      of the rubber timing chain tensioner and sure
                      enough when I pulled the front cover I saw that
                      the tensioner was non-existent and the chain
                      pretty loose.  I replaced the chain and
                      tensioner--not an easy job--and magically a
                      chattering sound that had been appearing at
                      certain rpm's disappeared, no doubt a harmonic
                      rattling of the loose timing chain.</div>
                    <div class="gmail_default"
                      style="color:rgb(51,51,255)"><br>
                    </div>
                    <div class="gmail_default"
                      style="color:rgb(51,51,255)">Best--Michael Oritt</div>
                  </div>
                  <br>
                  <div class="gmail_quote">
                    <div dir="ltr" class="gmail_attr">On Sun, Feb 21,
                      2021 at 12:17 PM Bob Spidell <<a
                        href="mailto:bspidell@comcast.net"
                        target="_blank" moz-do-not-send="true">bspidell@comcast.net</a>>
                      wrote:<br>
                    </div>
                    <blockquote class="gmail_quote" style="margin:0px
                      0px 0px 0.8ex;border-left:1px solid
                      rgb(204,204,204);padding-left:1ex">Most mechanics
                      favor modern 'top hat' style seals--I think
                      they're one <br>
                      piece--unless, of course, Concours Gold requires
                      blue smoke from the <br>
                      tailpipe.<br>
                      <br>
                      By no means let crumbling rubber parts see the
                      inside of an engine.<br>
                      <br>
                      Bob<br>
                      <br>
                      <br>
                      On 2/20/2021 9:28 PM, Alan Seigrist via Healeys
                      wrote:<br>
                      > All -<br>
                      ><br>
                      > On my A90 I am lapping one of the exhaust
                      valves and this seal came <br>
                      > off the upper part of the valve guide.<br>
                      ><br>
                      > It seems this is an original style valve seal
                      shroud which no one <br>
                      > sells.  I assume the best thing is to remove
                      it and chuck it, <br>
                      > correct?  It's already half disintegrated and
                      I'm not really worried <br>
                      > but would prefer to not  put it back on and
                      have old rubber parts <br>
                      > getting into the oil.<br>
                      ><br>
                      > Am I correct to not put it back on?  No one
                      seems to sell these.<br>
                      ><br>
                      > Best,<br>
                      ><br>
                      > Alan<br>
                      ><br>
                      ><br>
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