<html><body><br>Here is a note found on the web. Kinda explains the reasoning. However, I would talk to your machine shop and see what they recommend as technology has changed in 59-60 years. Today everything is about less drag. I have seen some folks leave off the bottom ring...I'm a purist, so I use original parts as they were manufactured. Hank<div><br></div><div><ul style="margin: 0px; padding: 0px; list-style: outside none; font-family: "helvetica neue", helvetica, arial, sans-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><li class="va-top ov-h" style="margin: 0px 0px 4px; padding: 0px; vertical-align: top; overflow: hidden; zoom: 1;">The oil control ring at the bottom actually consists of two rings and a spacer. The main trade off is, the 4-ring piston will have less drag on the cylinder walls, but the 5-ring piston will seal better. A better sealing piston will keep more power in the cylinder, but you'll see additional frictional losses.</li></ul><div class="reply-new-signature"></div><p>-----------------------------------------</p>From: "m.g.sharp--- via Healeys" <healeys@autox.team.net><br>To: "Ian Hey"<br>Cc: <br>Sent: Friday April 16 2021 12:18:04PM<br>Subject: Re: [Healeys] To fit or not to fit<br><br>
<div class="WordSection1">
<p class="MsoNormal">Hi Ian,</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">Thanks for responding. I am not going to
another piston manufacturer; the older AE pistons are excellent
quality and have a good reputation. You can’t judge the
quality of castings and machining from an illustration, and half
the time what is illustrated is not exactly what is sold anyhow.
Omega pistons are also excellent and I have fitted them to
classic BSA and Velocette motorcycles when I was doing a
complete balance, Carrillo rods, bench flowing the head; the
whole nine yards. However, with the Healey, unless you are
building a performance engine, I do not see the need for forged
pistons. That said, if I did not have the AE pistons, then I
would have gone with the Omegas.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal">I would still like to hear about the
purpose/wisdom behind the change in piston design that led to the
introduction of the 5<sup>th</sup> ring. They would not have
spent the extra money to switch up the machining if there was
not a good reason.</p>
<p class="MsoNormal"> </p>
<p class="MsoNormal"> </p>
<div>
<div style="border:none;border-top:solid #E1E1E1 1pt;padding:3pt 0cm 0cm 0cm;">
<p class="MsoNormal"><b><span lang="en-us">From:</span></b> <span lang="en-us">Healeys
<healeys-bounces@autox.team.net> <b>On Behalf Of</b> Ian Hey
via Healeys<br><b>Sent:</b> April 16, 2021 2:09 PM<br><b>To:</b> healeys@autox.team.net<br><b>Subject:</b> [Healeys] To fit or not to fit</span></p>
</div>
</div>
<p class="MsoNormal"> </p>
<p class="MsoNormal"><span lang="en-gb">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.</span></p>
<p class="MsoNormal"><span lang="en-gb"> </span></p>
<p class="MsoNormal"><span lang="en-gb">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)</span></p>
<p class="MsoNormal"><span lang="en-gb"> </span></p>
<p class="MsoNormal"><span lang="en-gb">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).</span></p>
<p class="MsoNormal"><span lang="en-gb"> </span></p>
<p class="MsoNormal"><span lang="en-gb">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.</span></p>
<p class="MsoNormal"><span lang="en-gb"> </span></p>
<p class="MsoNormal"><span lang="en-gb">Ian</span></p>
</div>
</healeys@autox.team.net></div></body></html>