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Enlarging the photo clearly shows beveling on the relief ports.<br>
<br>
<div class="moz-cite-prefix">On 3/26/2021 7:39 AM, Bob Spidell
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:92e66205-520f-9576-9e34-6fac1363fe92@comcast.net">
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OK, I did the hard work (2 clicks) and dug up the source:<br>
<br>
<a class="moz-txt-link-freetext"
href="https://www.ahspares.co.uk/austin-healey/performance-parts/gearbox-overdrive/o-ring-conversion-accumulator-piston.aspx"
moz-do-not-send="true">https://www.ahspares.co.uk/austin-healey/performance-parts/gearbox-overdrive/o-ring-conversion-accumulator-piston.aspx</a><br>
<br>
They claim the housing is modified as well, maybe with bevels on
the pressure relief ports?<br>
<br>
<div class="moz-cite-prefix">On 3/26/2021 7:34 AM, Michael Salter
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAB3i7L+uQF2sUaBVMdOAfW2s7gfiM55SippNqWfb7LVhUXkvow@mail.gmail.com">
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<div dir="ltr">
<div class="gmail_default" style="font-family:comic sans
ms,sans-serif;font-size:small"><span
style="font-family:arial,sans-serif">Bob, I looked into
installing "O" rings into an accumulator many years ago
but couldn't figure out how to get around the problem
presented by the fact that the accumulator relieves
pressure by allowing the cast iron rings to pass over
radial holes in the body.</span></div>
<div class="gmail_default" style="font-family:comic sans
ms,sans-serif;font-size:small"><span
style="font-family:arial,sans-serif">When I tried them the
"O" rings were forced into those pressure relief holes and
tiny pieces were sliced off at each hole location!!<br>
</span></div>
<div class="gmail_default" style="font-family:comic sans
ms,sans-serif;font-size:small"><span
style="font-family:arial,sans-serif">How do the
accumulators with "O" rings address that issue?</span></div>
<div class="gmail_default" style="font-family:comic sans
ms,sans-serif;font-size:small"><span
style="font-family:arial,sans-serif"><br>
</span></div>
<div class="gmail_default" style="font-family:comic sans
ms,sans-serif;font-size:small"><span
style="font-family:arial,sans-serif">M</span><br>
</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri, Mar 26, 2021 at
10:26 AM Bob Spidell <<a
href="mailto:bspidell@comcast.net" 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">
<div> Maybe of interest to some: AFAIK, all O/D accumulators
came with metal rings, which likely cause or at least
contribute to scoring. One of the Brit suppliers--probably
AHS but I'm not sure--has an accumulator setup that uses
an O-ring(s) instead of metal rings, which should prevent
scoring. I rebuilt my O/D a couple years back, and if I'd
known of the O-ring type I would have installed it.
Earlier O/Ds used metal rings in the actuator pistons, but
later ones had O-rings, and it's logical to conclude LdeN
went to O-rings there because of excessive scoring of the
cases (or, possibly, because they were cheaper).<br>
<br>
<div>On 3/26/2021 6:03 AM, Michael Salter via Healeys
wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">Time this question was put to bed.
<div dir="auto">1. The throttle switch is not supposed
to disengage the overdrive if the dash switch is in
the "OVERDRIVE" position. If it does the system is
wired incorrectly. (BN1s are a little different)</div>
<div dir="auto">2. Overdrives which slip out, slip, or
won't engage WHEN HOT but do work when cold are
invariably suffering from low oil pressure which is
almost always caused by accumulator issues. The "O"
rings on the outside of the accumulator sleeve can
be a problem but in my experience scoring of the
accumulator bore and damage to the rings and piston
are a more common cause.</div>
<div dir="auto">3. Overdrives and gearboxes in Healeys
are meant to be lubricated with engine oil. Decades
ago I wrote to Laycock DeNormanville, back when
letters went in envelopes with stamps, and received
a response from their engineering department
indicating clearly that the oil specified for their
products was specified by the gearbox manufacturer
and whatever they specified was acceptable for the
overdrive.</div>
<div dir="auto">M</div>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Fri., Mar. 26,
2021, 2:13 a.m. WILLIAM B LAWRENCE via Healeys, <<a
href="mailto:healeys@autox.team.net"
target="_blank" moz-do-not-send="true">healeys@autox.team.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">
<div>
<div>The symptoms I’ve seen and experienced are
that the OD will engage and function until the
oil temp comes up and the viscosity drops off
and will then fail. I suppose it depends on the
degree of degradation of the o-rings.</div>
<hr style="display:inline-block;width:98%">
<div
id="gmail-m_-7260173366705078485m_2913893478454826311divRplyFwdMsg"
dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Healeys <<a
href="mailto:healeys-bounces@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">healeys-bounces@autox.team.net</a>>
on behalf of Bob Spidell <<a
href="mailto:bspidell@comcast.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">bspidell@comcast.net</a>><br>
<b>Sent:</b> Thursday, March 25, 2021 11:14 PM<br>
<b>To:</b> <a
href="mailto:healeys@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">healeys@autox.team.net</a>
<<a href="mailto:healeys@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">healeys@autox.team.net</a>><br>
<b>Subject:</b> Re: [Healeys] overdrive
problem</font>
<div> </div>
</div>
<div>Sure, but wouldn't faulty O-rings prevent the
OD from engaging in the first place? Just
guessing, but wouldn't a deficient pump cause
same symptoms?<br>
<br>
<br>
<div>On 3/25/2021 4:07 PM, WILLIAM B LAWRENCE
via Healeys wrote:<br>
</div>
<blockquote type="cite">
<div>Sorry, but the Laycock deNormanville
overdrive is not supposed to kick down
automatically. The most common fault that
causes the OD to drop out is faulty o-rings
on the accumulator sleeve. This won’t allow
the OD to build full operating pressure.</div>
<div><br>
</div>
<div>Bill Lawrence</div>
<div>BN1 #554</div>
<hr style="display:inline-block;width:98%">
<div
id="gmail-m_-7260173366705078485m_2913893478454826311x_divRplyFwdMsg"
dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Healeys <a
href="mailto:healeys-bounces@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true"><healeys-bounces@autox.team.net></a>
on behalf of Kees Oudesluijs via Healeys <a
href="mailto:healeys@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true"><healeys@autox.team.net></a><br>
<b>Sent:</b> Tuesday, March 23, 2021 7:37
AM<br>
<b>To:</b> <a
href="mailto:healeys@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">
healeys@autox.team.net</a> <a
href="mailto:healeys@autox.team.net"
rel="noreferrer" target="_blank"
moz-do-not-send="true">
<healeys@autox.team.net></a><br>
<b>Subject:</b> Re: [Healeys] overdrive
problem</font>
<div> </div>
</div>
<div><font size="2"><span
style="font-size:11pt">
<div>That is the way it should be when
accelerating hard, Kick down!!<br>
<br>
Kees Oudesluijs<br>
<br>
<br>
Op 23-3-2021 om 01:06 schreef
healeymanjim via Healeys:<br>
> friends BT7 had o/d quit.
solenoid was bad so replaced it. now
it will go into o/d but pop out when
accelerating. any<br>
> ideas what the cause is and the
fix?<br>
</div>
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