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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>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Sent from <a
href="https://go.microsoft.com/fwlink/?LinkId=550986"
moz-do-not-send="true">Mail</a> for Windows</p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">This was the condition of my piston and
housing with close to 200,000 miles. Tranny was well
maintained.<o:p></o:p></p>
<p class="MsoNormal">The original metal rings lasted 53 years.
So I guess with unknown quality of either of todays metal vs
rubber<o:p></o:p></p>
<p class="MsoNormal">O rings, let the experiments begin. <o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="border:none;padding:0in"><b>From:
</b><a href="mailto:bspidell@comcast.net"
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"
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>
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<p class="MsoNormal"><o:p> </o:p></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?).<br>
<br>
<o:p></o:p></p>
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<p class="MsoNormal">On 8/3/2022 12:36 PM, Henry G Leach via
Healeys wrote:<o:p></o:p></p>
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<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. <o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<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.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<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<o:p></o:p></p>
<p>-----------------------------------------</p>
<p class="MsoNormal" style="margin-bottom:12.0pt">From:
"Michael Salter" <br>
To: <a href="mailto:healeys@autox.team.net"
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<o:p></o:p></p>
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<div>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",sans-serif">I
have a question about the "O" ring type of
accumulator.<o:p></o:p></span></p>
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<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",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.<o:p></o:p></span></p>
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<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",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.<o:p></o:p></span></p>
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<div>
<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",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.<o:p></o:p></span></p>
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<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",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?<o:p></o:p></span></p>
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<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span
style="font-size:12.0pt;font-family:"Arial",sans-serif">M<o:p></o:p></span></p>
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style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p> </o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Wed, Aug 3, 2022 at 9:08 AM Bob
Spidell <a class="moz-txt-link-rfc2396E" href="mailto:bspidell@comcast.net"><bspidell@comcast.net></a> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt">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>
> Has anyone installed their upgraded overdrive
piston? If so, is it<br>
> worth the trouble ?<br>
><br>
> Joe<br>
> BN1 #923<br>
><o:p></o:p></p>
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