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Re: [Healeys] DW overdrive piston

To: Michael Salter <michaelsalter@gmail.com>, Warren Dietz <flyhihealey@gmail.com>
Subject: Re: [Healeys] DW overdrive piston
From: Bob Spidell <bspidell@comcast.net>
Date: Thu, 4 Aug 2022 10:12:30 -0700
Cc: "healeys@autox.team.net" <healeys@autox.team.net>
Delivered-to: mharc@autox.team.net
Delivered-to: healeys@autox.team.net
References: <519f18752779101056fc889c22a7b3fe696ee5a5@webmail> <c4313728-47ce-94f0-ed12-a6899978d67a@comcast.net> <C2F28F01-83FF-4774-B922-022773FD3F35@hxcore.ol> <ddc02db1-7316-fa91-f5c9-f6a4df15c148@comcast.net> <B06F3144-B35B-4D86-815A-59F470CC4365@hxcore.ol> <CAB3i7LL54tH+2nE6eQeDcqVwP2VMjc4k0LCm+NsXrQ+C7LpncA@mail.gmail.com>
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OK, who sells magnetic plugs for MOWOG gearboxes? I'd be willing to 
order from Canada ;)

I don't remember exactly when I started using MT-90 in my gearbox, but 
it was probably around 90-100K miles. I was hoping it would make the O/D 
a bit more responsive, but was surprised that shifting seemed smoother 
(I wasn't expecting it, so little-no confirmation bias).


On 8/4/2022 9:38 AM, Michael Salter wrote:
> Based upon my observations when the aluminium overdrive accumulator 
> housings are scored you will invariably find that there are chips out 
> of the non syncro 1st and reverse gears and usually badly damaged 
> laygear rollers.
> Because these gearboxes were not fitted with chip gathering magnet 
> originally the tiny hardened steel chips eventually find their way 
> into the overdrive then through the overdrive pump gauze (because the 
> magnets originally fitted in the overdrive have been lost by " the 
> lube guy") and lodge in the accumulator.
> Those chips very quickly score the cylinder as the accumulator piston 
> moves.
> If you are careful to never grind 1st or reverse no chips will be 
> created, that will mean that they don't go through the laygear 
> bearings or find their way into the overdrive.
> A magnetic plug in the gearbox is great insurance.
>
> M
>
> On Thu., Aug. 4, 2022, 12:13 p.m. Warren Dietz, 
> <flyhihealey@gmail.com> wrote:
>
>     Bob,
>
>     Interesting observation.
>
>     Only 30/40 wt non detergent oil was used from new till 2013  at
>     which time I switched
>
>     to Redline MT90 @ 181,000 miles.
>
>     Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986>
>     for Windows
>
>     *Sent: *Thursday, August 4, 2022 9:38 AM
>     healeys@autox.team.net
>     *Subject: *Re: [Healeys] DW overdrive piston
>
>     Warren,
>
>     Your accumulator piston and housing look to have a bit worse
>     scoring than mine; I used synthetic fluid for over half the life
>     of mine, I wonder if that made a difference?
>
>
>
>         Sent from Mail
>         <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
>
>         This was the condition of my piston and housing with close to
>         200,000 miles. Tranny was well maintained.
>
>         The original metal rings lasted 53 years. So I guess with
>         unknown quality of either of todays metal vs rubber
>
>         O rings, let the experiments begin.
>
>         *Sent: *Wednesday, August 3, 2022 10:12 PM
>         *To: *healeys@autox.team.net
>         *Subject: *Re: [Healeys] DW overdrive piston
>
>         The rings will score the inside of the piston housing, though
>         not badly (photo at 205K miles). Looks like there's a side
>         load on the piston, probably from the spring.
>
>         I donated this accumulator to another owner; never heard how
>         they worked. Moss shows the rings available (but who knows?).
>
>         On 8/3/2022 12:36 PM, Henry G Leach via Healeys wrote:
>
>             I assemble ODs using the original metal rings and have not
>             had any issues with pressure or engagement/disengagement.
>
>             When Mr. DeNormanville stayed up in the middle of the
>             night to engineer the operation of the unit,  I think he
>             decided that the use of softer rings (sacrificial metal)
>             against a hardened casing was the best solution for
>             control and wear.  If a rubber o-ring was a better
>             solution, he would have used one with the proper buna rating.
>
>             I think the bigger problem, now-a-days, is the
>             availability of the metal piston rings.  Rubber O rings
>             are a dime-a-dozen.  If you contact Overdrive Spares in
>             the UK, they should be able to supply the proper rings. 
>             If they too, have decided to go with rubber, then plan on
>             a breakdown/rebuild in a shorter period of time than units
>             equipped with the original parts that last a long, long
>             time. Hank
>
>             -----------------------------------------
>
>             From: "Michael Salter"
>             Cc:
>             Sent: Wednesday August 3 2022 9:38:15AM
>             Subject: Re: [Healeys] DW overdrive piston
>
>             I have a question about the "O" ring type of accumulator.
>
>             The way the accumulator works is that when it is fully
>             charged the piston moves against the spring until the
>             rings reach the radial holes in the wall of the housing
>             which acts to relieve any excess pressure.
>
>             My concern is that at 3 - 400 p.s.i. oil will obviously
>             get behind the "O" ring and force the material of the "O"
>             ring into those radial holes and then, as the piston moves
>             back over them, a piece of the ring will shear off.
>
>             I'm guessing that Laycock-DeNormanville used the complex
>             cast iron rings rather than "O" rings because they
>             recognized the possibility of this happening.
>
>             I'm sure that tiny pieces of the "O" ring would be found
>             in the filter if this was a problem. Anyone found them or
>             noticed damage to their accumulator "O" ring upon disassembly?
>
>             M
>
>             On Wed, Aug 3, 2022 at 9:08 AM Bob Spidell
>
>                 I put one in my BJ8's O/D. It's subjective*--O/Ds seem
>                 to work a little
>                 quicker with cold, thick oil than hot oil--but it cuts
>                 maybe a third off
>                 engagement time on average. I had the O/D on the bench
>                 and disassembled,
>                 and the current one had a scored barrel so, why not?
>                 Engagement isn't
>                 much, if any, harsher than before which, I believe is
>                 the reason DMH
>                 wanted the weaker, smaller spring. If I'd known about
>                 it, I might have
>                 bought AHSpares' with an O-ring instead.
>
>                 * I've never really 'timed' O/D functioning, it would
>                 be a bit awkward;
>                 anyone done it? I usually tap the clutch pedal when
>                 engaging O/D, and
>                 give a little throttle when disengaging. I thought
>                 mine engaged a little
>                 quicker when I switched to synthetic fluid from engine
>                 oil, but in all
>                 cases confirmation bias may be involved.
>
>
>
>                 On 8/2/2022 8:09 PM, Joseph Costa wrote:
>                 > Has anyone installed their upgraded overdrive
>                 piston?  If so, is it
>                 > worth the trouble ?
>                 >
>                 > Joe
>                 > BN1 #923
>                 >
>
>

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    OK, who sells magnetic plugs for MOWOG gearboxes? I'd be willing to
    order from Canada ;)<br>
    <br>
    I don't remember exactly when I started using MT-90 in my gearbox,
    but it was probably around 90-100K miles. I was hoping it would make
    the O/D a bit more responsive, but was surprised that shifting
    seemed smoother (I wasn't expecting it, so little-no confirmation
    bias). <br>
    <br>
    <br>
    <div class="moz-cite-prefix">On 8/4/2022 9:38 AM, Michael Salter
      wrote:<br>
    </div>
    <blockquote type="cite"
cite="mid:CAB3i7LL54tH+2nE6eQeDcqVwP2VMjc4k0LCm+NsXrQ+C7LpncA@mail.gmail.com">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      <div dir="auto">Based upon my observations when the aluminium
        overdrive accumulator housings are scored you will invariably
        find that there are chips out of the non syncro 1st and reverse
        gears and usually badly damaged laygear rollers.
        <div dir="auto">Because these gearboxes were not fitted with
          chip gathering magnet originally the tiny hardened steel chips
          eventually find their way into the overdrive then through the
          overdrive pump gauze (because the magnets originally fitted in
          the overdrive have been lost by " the lube guy") and lodge in
          the accumulator. </div>
        <div dir="auto">Those chips very quickly score the cylinder as
          the accumulator piston moves.</div>
        <div dir="auto">If you are careful to never grind 1st or reverse
          no chips will be created, that will mean that they don't go
          through the laygear bearings or find their way into the
          overdrive. </div>
        <div dir="auto">A magnetic plug in the gearbox is great
          insurance.</div>
        <div dir="auto"><br>
        </div>
        <div dir="auto">M</div>
      </div>
      <br>
      <div class="gmail_quote">
        <div dir="ltr" class="gmail_attr">On Thu., Aug. 4, 2022, 12:13
          p.m. Warren Dietz, &lt;<a href="mailto:flyhihealey@gmail.com";
            moz-do-not-send="true" 
class="moz-txt-link-freetext">flyhihealey@gmail.com</a>&gt;
          wrote:<br>
        </div>
        <blockquote class="gmail_quote" style="margin:0 0 0
          .8ex;border-left:1px #ccc solid;padding-left:1ex">
          <div link="blue" vlink="#954F72" style="word-wrap:break-word"
            lang="EN-US">
            <div class="m_-3387470703538253816WordSection1">
              <p class="MsoNormal">Bob,</p>
              <p class="MsoNormal">Interesting observation.</p>
              <p class="MsoNormal">Only 30/40 wt non detergent oil was
                used from new till 2013  at which time I switched</p>
              <p class="MsoNormal">to Redline MT90 @ 181,000 miles.</p>
              <p class="MsoNormal"> </p>
              <p class="MsoNormal">Sent from <a
                  href="https://go.microsoft.com/fwlink/?LinkId=550986";
                  target="_blank" rel="noreferrer"
                  moz-do-not-send="true">Mail</a> for Windows</p>
              <p class="MsoNormal"> </p>
              <div style="border:none;border-top:solid #e1e1e1
                1.0pt;padding:3.0pt 0in 0in 0in">
                <p class="MsoNormal" style="border:none;padding:0in"><b>From:
                  </b><a href="mailto:bspidell@comcast.net";
                    target="_blank" rel="noreferrer"
                    moz-do-not-send="true">Bob Spidell</a><br>
                  <b>Sent: </b>Thursday, August 4, 2022 9:38 AM<br>
                  <b>To: </b><a href="mailto:flyhihealey@gmail.com";
                    target="_blank" rel="noreferrer"
                    moz-do-not-send="true">Warren Dietz</a>; <a
                    href="mailto:healeys@autox.team.net"; target="_blank"
                    rel="noreferrer" moz-do-not-send="true"
                    class="moz-txt-link-freetext">healeys@autox.team.net</a><br>
                  <b>Subject: </b>Re: [Healeys] DW overdrive piston</p>
              </div>
              <p class="MsoNormal"> </p>
              <p class="MsoNormal">Warren,<br>
                <br>
                Your accumulator piston and housing look to have a bit
                worse scoring than mine; I used synthetic fluid for over
                half the life of mine, I wonder if that made a
                difference?<br>
                <br>
                <br>
                <br>
              </p>
              <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
                <p class="MsoNormal"> </p>
                <p class="MsoNormal"> </p>
                <p class="MsoNormal">Sent from <a
                    href="https://go.microsoft.com/fwlink/?LinkId=550986";
                    target="_blank" rel="noreferrer"
                    moz-do-not-send="true">Mail</a> for Windows</p>
                <p class="MsoNormal"> </p>
                <p class="MsoNormal">This was the condition of my piston
                  and housing with close to 200,000 miles. Tranny was
                  well maintained.</p>
                <p class="MsoNormal">The original metal rings lasted 53
                  years. So I guess with unknown quality of either of
                  todays metal vs rubber</p>
                <p class="MsoNormal">O rings, let the experiments begin.
                </p>
                <p class="MsoNormal"> </p>
                <p class="MsoNormal"> </p>
                <p class="MsoNormal"> </p>
                <div style="border:none;border-top:solid #e1e1e1
                  1.0pt;padding:3.0pt 0in 0in 0in">
                  <p class="MsoNormal"><b>From: </b><a
                      href="mailto:bspidell@comcast.net"; target="_blank"
                      rel="noreferrer" moz-do-not-send="true">Bob
                      Spidell</a><br>
                    <b>Sent: </b>Wednesday, August 3, 2022 10:12 PM<br>
                    <b>To: </b><a href="mailto:healeys@autox.team.net";
                      target="_blank" rel="noreferrer"
                      moz-do-not-send="true"
                      
class="moz-txt-link-freetext">healeys@autox.team.net</a><br>
                    <b>Subject: </b>Re: [Healeys] DW overdrive piston</p>
                </div>
                <p class="MsoNormal"> </p>
                <p class="MsoNormal" style="margin-bottom:12.0pt">The
                  rings will score the inside of the piston housing,
                  though not badly (photo at 205K miles). Looks like
                  there's a side load on the piston, probably from the
                  spring.<br>
                  <br>
                  I donated this accumulator to another owner; never
                  heard how they worked. Moss shows the rings available
                  (but who knows?).</p>
                <div>
                  <p class="MsoNormal">On 8/3/2022 12:36 PM, Henry G
                    Leach via Healeys wrote:</p>
                </div>
                <blockquote style="margin-top:5.0pt;margin-bottom:5.0pt">
                  <p class="MsoNormal">I assemble ODs using the original
                    metal rings and have not had any issues with
                    pressure or engagement/disengagement. </p>
                  <div>
                    <p class="MsoNormal"> </p>
                  </div>
                  <div>
                    <p class="MsoNormal">When Mr. DeNormanville stayed
                      up in the middle of the night to engineer the
                      operation of the unit,  I think he decided that
                      the use of softer rings (sacrificial metal)
                      against a hardened casing was the best solution
                      for control and wear.  If a rubber o-ring was a
                      better solution, he would have used one with the
                      proper buna rating.</p>
                  </div>
                  <div>
                    <p class="MsoNormal"> </p>
                  </div>
                  <div>
                    <p class="MsoNormal" style="margin-bottom:12.0pt">I
                      think the bigger problem, now-a-days, is the
                      availability of the metal piston rings.  Rubber O
                      rings are a dime-a-dozen.  If you contact
                      Overdrive Spares in the UK, they should be able to
                      supply the proper rings.  If they too, have
                      decided to go with rubber, then plan on a
                      breakdown/rebuild in a shorter period of time than
                      units equipped with the original parts that last a
                      long, long time. Hank</p>
                    <p>-----------------------------------------</p>
                    <p class="MsoNormal" style="margin-bottom:12.0pt">From:
                      "Michael Salter" <br>
                      To: <a href="mailto:healeys@autox.team.net";
                        target="_blank" rel="noreferrer"
                        moz-do-not-send="true">"healeys@autox.team.net"</a><br>
                      Cc: <br>
                      Sent: Wednesday August 3 2022 9:38:15AM<br>
                      Subject: Re: [Healeys] DW overdrive piston</p>
                    <div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">I
                            have a question about the "O" ring type of
                            accumulator.</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">The
                            way the accumulator works is that when it is
                            fully charged the piston moves against the
                            spring until the rings reach the radial
                            holes in the wall of the housing which acts
                            to relieve any excess pressure.</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">My
                            concern is that at 3 - 400 p.s.i. oil will
                            obviously get behind the "O" ring and force
                            the material of the "O" ring into those
                            radial holes and then, as the piston moves
                            back over them, a piece of the ring will
                            shear off.</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">I'm
                            guessing that Laycock-DeNormanville used the
                            complex cast iron rings rather than "O"
                            rings because they recognized the
                            possibility of this happening.</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">I'm
                            sure that tiny pieces of the "O" ring would
                            be found in the filter if this was a
                            problem. Anyone found them or noticed damage
                            to their accumulator "O" ring upon
                            disassembly?</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif"> </span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif">M</span></p>
                      </div>
                      <div>
                        <p class="MsoNormal"><span
                            
style="font-size:12.0pt;font-family:&quot;Arial&quot;,sans-serif"> </span></p>
                      </div>
                    </div>
                    <p class="MsoNormal"> </p>
                    <div>
                      <div>
                        <p class="MsoNormal">On Wed, Aug 3, 2022 at 9:08
                          AM Bob Spidell <a
                            href="mailto:bspidell@comcast.net";
                            target="_blank" rel="noreferrer"
                            
moz-do-not-send="true">&lt;bspidell@comcast.net&gt;</a>
                          wrote:</p>
                      </div>
                      <blockquote style="border:none;border-left:solid
                        #cccccc 1.0pt;padding:0in 0in 0in
6.0pt;margin-left:4.8pt;margin-top:5.0pt;margin-right:0in;margin-bottom:5.0pt">
                        <p class="MsoNormal"
                          
style="margin-right:0in;margin-bottom:12.0pt;margin-left:153.6pt">I
                          put one in my BJ8's O/D. It's
                          subjective*--O/Ds seem to work a little<br>
                          quicker with cold, thick oil than hot oil--but
                          it cuts maybe a third off<br>
                          engagement time on average. I had the O/D on
                          the bench and disassembled,<br>
                          and the current one had a scored barrel so,
                          why not? Engagement isn't<br>
                          much, if any, harsher than before which, I
                          believe is the reason DMH<br>
                          wanted the weaker, smaller spring. If I'd
                          known about it, I might have<br>
                          bought AHSpares' with an O-ring instead.<br>
                          <br>
                          * I've never really 'timed' O/D functioning,
                          it would be a bit awkward;<br>
                          anyone done it? I usually tap the clutch pedal
                          when engaging O/D, and<br>
                          give a little throttle when disengaging. I
                          thought mine engaged a little<br>
                          quicker when I switched to synthetic fluid
                          from engine oil, but in all<br>
                          cases confirmation bias may be involved.<br>
                          <br>
                          <br>
                          <br>
                          On 8/2/2022 8:09 PM, Joseph Costa wrote:<br>
                          &gt; Has anyone installed their upgraded
                          overdrive piston?  If so, is it<br>
                          &gt; worth the trouble ?<br>
                          &gt;<br>
                          &gt; Joe<br>
                          &gt; BN1 #923<br>
                          &gt;</p>
                      </blockquote>
                    </div>
                  </div>
                </blockquote>
                <br>
              </blockquote>
            </div>
          </div>
        </blockquote>
      </div>
    </blockquote>
    <br>
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