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Current engine thinking is to move the wrist pin closer to the top of
the piston and to reduce the length of the piston (shorter skirts) and
zero quench (piston rises above the deck level). The 5th oil control
ring served the purpose of (oil control) and also to minimize piston
slap on the cylinder wall as the piston reversed direction leading to
cylinder wall ovalization and subsequent loss of compression. Dave
On 4/18/2021 4:54 PM, Michael MacLean via Healeys wrote:
> I don't know about the six cylinder engines, but during the rebuild of
> my BN2 engine I used 3 ring pistons from Moss. Not exactly the most
> exclusive examples of piston technology, but the very experienced
> engine builder that built my shot block for me said they will do just
> fine. Heck I don't even remember seeing an oil scraper ring on them.Â
> Not an expert, but could the way the bottom ring was ground to shape
> have an oil scraping purpose?
> Mike MacLean
> Out of my five vehicles, only one has a catalytic converter. Take
> that Greta Thunberg.
>
> Sent from AT&T Yahoo Mail on Android
> <https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature>
>
> On Sat, Apr 17, 2021 at 4:37 PM, William Atterbury via Healeys
> <healeys@autox.team.net> wrote:
> Hey Ian,
> The rumor I heard was that the 5th ring was for hone-and-replace
> rebuilds to reduce oil consumption. I'll let others comment if
> these cars were fitted with 4 or 5 rings from the factory (I'm
> guessing 4). I rebuilt mine with 4, like the others. Not a
> problem for our coddled Healeys. Heck, I even know of one fellow
> who only put in three for a hot motor.
>
> Bill Atterbury
> BT7
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 16 Apr 2021 19:08:56 +0100
> From: "Ian Hey" <rianhey@btinternet.com
> Subject: [Healeys] To fit or not to fit
> Message-ID: <002201d732eb$915662a0$b40327e0$@btinternet.com>
> Content-Type: text/plain; charset="us-ascii"
>
> In a recent engine rebuild of a standard BJ7 engine which was
> fitted with
> four ring pistons, when I looked at replacement pistons they were
> pictured
> with five rings, which did not seem good to me.
>
> I fitted Omega pistons from Denis Welch. These have three rings
> with a
> total width of 3.2mm compared with 9.8mm for the four rings. (For
> the oil
> rings only the width contacting the cylinder bore is measured
>
> Since friction is in proportion to ring width (possibly due to the
> lower
> pressure required to make thinner rings seat against the cylinder
> wall) this
> represents a reduction in losses to heat and a power increase (small).
>
> Another, much more expensive, option for consideration. I also
> have no
> doubts about the quality of the pistons, whereas I am not sure
> about the
> four or five ringed replacements. They seem very cheap to me.
>
> Ian
>
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>
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--
Porter Custom Bicycles 2909 Arno St. NE Albuquerque, NM. 505-352-1378 My World
go here: WWW.PORTERBIKES.COM/
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<p>Current engine thinking is to move the wrist pin closer to the
top of the piston and to reduce the length of the piston (shorter
skirts) and zero quench (piston rises above the deck level). The
5th oil control ring served the purpose of (oil control) and also
to minimize piston slap on the cylinder wall as the piston
reversed direction leading to cylinder wall ovalization and
subsequent loss of compression. Dave<br>
</p>
<div class="moz-cite-prefix">On 4/18/2021 4:54 PM, Michael MacLean
via Healeys wrote:<br>
</div>
<blockquote type="cite"
cite="mid:1959093511.3621729.1618786496615@mail.yahoo.com">
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
I don't know about the six cylinder engines, but during the
rebuild of my BN2 engine I used 3 ring pistons from Moss. Not
exactly the most exclusive examples of piston technology, but the
very experienced engine builder that built my shot block for me
said they will do just fine. Heck I don't even remember seeing an
oil scraper ring on them. Not an expert, but could the way the
bottom ring was ground to shape have an oil scraping purpose?
<div id="yMail_cursorElementTracker_1618786399393">Mike MacLean </div>
<div id="yMail_cursorElementTracker_1618786421646">Out of my five
vehicles, only one has a catalytic converter. Take that Greta
Thunberg.<br>
<br>
<div id="ymail_android_signature"><a
id="ymail_android_signature_link"
href="https://go.onelink.me/107872968?pid=InProduct&c=Global_Internal_YGrowth_AndroidEmailSig__AndroidUsers&af_wl=ym&af_sub1=Internal&af_sub2=Global_YGrowth&af_sub3=EmailSignature";
moz-do-not-send="true">Sent from AT&T Yahoo Mail on
Android</a></div>
<br>
<blockquote style="margin: 0 0 20px 0;">
<div style="font-family:Roboto, sans-serif; color:#6D00F6;">
<div>On Sat, Apr 17, 2021 at 4:37 PM, William Atterbury via
Healeys</div>
<div><a class="moz-txt-link-rfc2396E"
href="mailto:healeys@autox.team.net";><healeys@autox.team.net></a>
wrote:</div>
</div>
<div style="padding: 10px 0 0 20px; margin: 10px 0 0 0;
border-left: 1px solid #6D00F6;">
<div id="yiv5269241550">
<div>
<div class="yiv5269241550ydpf5e37345yahoo-style-wrap"
style="font-family:Helvetica Neue, Helvetica, Arial,
sans-serif;font-size:16px;">
<div dir="ltr">
<div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Hey Ian,</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">The rumor I heard
was that the 5th ring was for hone-and-replace
rebuilds to reduce oil consumption. I'll let
others comment if these cars were fitted with 4
or 5 rings from the factory (I'm guessing 4). I
rebuilt mine with 4, like the others. Not a
problem for our coddled Healeys. Heck, I even
know of one fellow who only put in three for a
hot motor.</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Bill Atterbury</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">BT7</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial,
sans-serif;">----------------------------------------------------------------------<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Message: 1<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Date: Fri, 16 Apr
2021 19:08:56 +0100<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">From: "Ian Hey"
<<a rel="nofollow noopener noreferrer"
ymailto="mailto:rianhey@btinternet.com";
target="_blank"
href="mailto:rianhey@btinternet.com";
style="color:rgb(25, 106,
212);text-decoration-line:underline;"
moz-do-not-send="true">rianhey@btinternet.com</a>><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">To: <<a
rel="nofollow noopener noreferrer"
ymailto="mailto:healeys@autox.team.net";
target="_blank"
href="mailto:healeys@autox.team.net";
style="color:rgb(25, 106,
212);text-decoration-line:underline;"
moz-do-not-send="true">healeys@autox.team.net</a>><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Subject:
[Healeys] To fit or not to fit<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Message-ID:
<a class="moz-txt-link-rfc2396E"
href="mailto:002201d732eb$915662a0$b40327e0$@btinternet.com";><002201d732eb$915662a0$b40327e0$@btinternet.com></a><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Content-Type:
text/plain; charset="us-ascii"<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">In a recent
engine rebuild of a standard BJ7 engine which
was fitted with<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">four ring
pistons, when I looked at replacement pistons
they were pictured<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">with five rings,
which did not seem good to me.<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">I fitted Omega
pistons from Denis Welch. These have three
rings with a<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">total width of
3.2mm compared with 9.8mm for the four rings.Â
(For the oil<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">rings only the
width contacting the cylinder bore is measured</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Since friction is
in proportion to ring width (possibly due to the
lower<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">pressure required
to make thinner rings seat against the cylinder
wall) this<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">represents a
reduction in losses to heat and a power increase
(small).<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Another, much
more expensive, option for consideration. I
also have no<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">doubts about the
quality of the pistons, whereas I am not sure
about the<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">four or five
ringed replacements. They seem very cheap to
me.<br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;"><br>
</div>
<div dir="ltr" style="font-family:Helvetica Neue,
Helvetica, Arial, sans-serif;">Ian</div>
</div>
<br>
</div>
</div>
</div>
</div>
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</blockquote>
</div>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre"
wrap="">_______________________________________________
Archive: <a class="moz-txt-link-freetext"
href="http://www.team.net/pipermail/healeys";>http://www.team.net/pipermail/healeys</a>
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</pre>
</blockquote>
<pre class="moz-signature" cols="72">--
Porter Custom Bicycles 2909 Arno St. NE Albuquerque, NM. 505-352-1378 My World
go here: <a class="moz-txt-link-abbreviated"
href="http://WWW.PORTERBIKES.COM/";>WWW.PORTERBIKES.COM/</a></pre>
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