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=0AHere is a note found on the web. Kinda explains the reasoning.=0AHowe=
ver, I would talk to your machine shop and see what they recommend=0Aas=
technology has changed in 59-60 years. Today everything is about=0Aless=
drag. I have seen some folks leave off the bottom ring...I'm a=0Apurist=
, so I use original parts as they were manufactured. Hank=0A=0A=09* The=
oil control ring at the bottom actually consists of two rings=0Aand a s=
pacer. The main trade off is, the 4-ring piston will have less=0Adrag on=
the cylinder walls, but the 5-ring piston will seal better. A=0Abetter=
sealing piston will keep more power in the cylinder, but you'll=0Asee a=
dditional frictional losses.=0A=0A=09-----------------------------------=
------From: "m.g.sharp--- via=0AHealeys" =0ATo: "Ian Hey"=0ACc: =0ASent:=
Friday April 16 2021 12:18:04PM=0ASubject: Re: [Healeys] To fit or not=
to fit=0A=0A=09Hi Ian, =0A=0A=09Thanks for responding. I am not going t=
o another piston manufacturer;=0Athe older AE pistons are excellent qual=
ity and have a good reputation.=0AYou can=E2=80=99t judge the quality of=
castings and machining from an=0Aillustration, and half the time what i=
s illustrated is not exactly=0Awhat is sold anyhow. Omega pistons are al=
so excellent and I have=0Afitted them to classic BSA and Velocette motor=
cycles when I was doing=0Aa complete balance, Carrillo rods, bench flowi=
ng the head; the whole=0Anine yards. However, with the Healey, unless yo=
u are building a=0Aperformance engine, I do not see the need for forged=
pistons. That=0Asaid, if I did not have the AE pistons, then I would ha=
ve gone with=0Athe Omegas. =0A=0A=09I would still like to hear about the=
purpose/wisdom behind the change=0Ain piston design that led to the int=
roduction of the 5th ring. They=0Awould not have spent the extra money t=
o switch up the machining if=0Athere was not a good reason. =0A=0A=09FRO=
M: Healeys ON BEHALF OF Ian Hey via Healeys=0ASENT: April 16, 2021 2:09=
PM=0ATO: healeys@autox.team.net=0ASUBJECT: [Healeys] To fit or not to f=
it =0A=0A=09In a recent engine rebuild of a standard BJ7 engine which=
was fitted=0Awith four ring pistons, when I looked at replacement pisto=
ns they were=0Apictured with five rings, which did not seem good to me.=
=0A=0A=09I fitted Omega pistons from Denis Welch. These have three ring=
s with=0Aa total width of 3.2mm compared with 9.8mm for the four rings.=
(For=0Athe oil rings only the width contacting the cylinder bore is mea=
sured)=0A=0A=0A=09Since friction is in proportion to ring width (possibl=
y due to the=0Alower pressure required to make thinner rings seat agains=
t the=0Acylinder wall) this represents a reduction in losses to heat and=
a=0Apower increase (small). =0A=0A=09Another, much more expensive, opti=
on for consideration. I also have=0Ano doubts about the quality of the p=
istons, whereas I am not sure=0Aabout the four or five ringed replacemen=
ts. They seem very cheap to=0Ame. =0A=0A=09Ian
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<html><body><br>Here is a note found on the web. Kinda explains the reas=
oning. However, I would talk to your machine shop and see what they reco=
mmend as technology has changed in 59-60 years. Today everything i=
s 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=3D"margin: 0px; padding: 0px; list-style: outsi=
de none; font-family: "helvetica neue", helvetica, arial, sans=
-serif; font-size: 16px; background-color: rgb(255, 255, 255);"><li clas=
s=3D"va-top ov-h" style=3D"margin: 0px 0px 4px; padding: 0px; vertical-a=
lign: top; overflow: hidden; zoom: 1;">The oil control ring at=
the bottom actually consists of two rings and a spacer. The m=
ain 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=3D"rep=
ly-new-signature"></div><p>-----------------------------------------</p>=
From: "m.g.sharp--- via Healeys" <healeys@autox.team.net><br>To: "Ian He=
y"<br>Cc: <br>Sent: Friday April 16 2021 12:18:04PM<br>Subject: Re: [Hea=
leys] To fit or not to fit<br><br>=0A<div class=3D"WordSection1">=0A<p c=
lass=3D"MsoNormal">Hi Ian,</p>=0A<p class=3D"MsoNormal"> </p>=0A<p=
class=3D"MsoNormal">Thanks for responding. I am not going to=0Aan=
other piston manufacturer; the older AE pistons are excellent=0Aquality=
and have a good reputation. You can=E2=80=99t judge the=0Aquality=
of castings and machining from an illustration, and half=0Athe time wha=
t is illustrated is not exactly what is sold anyhow.=0A Omega pisto=
ns are also excellent and I have fitted them to=0Aclassic BSA and Veloce=
tte motorcycles when I was doing a=0Acomplete balance, Carrillo ro=
ds, bench flowing the head; the=0Awhole nine yards. However, with=
the Healey, unless you are=0Abuilding a performance engine, I do not se=
e the need for forged=0Apistons. That said, if I did not have the=
AE pistons, then I=0Awould have gone with the Omegas.</p>=0A<p class=3D=
"MsoNormal"> </p>=0A<p class=3D"MsoNormal">I would still like to he=
ar about the=0Apurpose/wisdom behind the change in piston design that le=
d to the=0Aintroduction of the 5<sup>th</sup> ring. They would not=
have=0Aspent the extra money to switch up the machining if there=
was=0Anot a good reason.</p>=0A<p class=3D"MsoNormal"> </p>=0A<p c=
lass=3D"MsoNormal"> </p>=0A<div>=0A<div style=3D"border:none;border=
-top:solid #E1E1E1 1pt;padding:3pt 0cm 0cm 0cm;">=0A<p class=3D"MsoNorma=
l"><b><span lang=3D"en-us">From:</span></b> <span lang=3D"en-us">Healeys=
=0A<healeys-bounces@autox.team.net> <b>On Behalf Of</b> Ian Hey=0A=
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>=0A</div>=0A</div>=0A<p class=3D"MsoNormal"> </p>=0A<p class=3D=
"MsoNormal"><span lang=3D"en-gb">In a recent engine rebuild=0Aof a stand=
ard BJ7 engine which was fitted with four ring pistons,=0Awhen I looked=
at replacement pistons they were pictured with five=0Arings, which did=
not seem good to me.</span></p>=0A<p class=3D"MsoNormal"><span lang=3D"=
en-gb"> </span></p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb">I=
fitted Omega pistons from=0ADenis Welch. These have three rings w=
ith a total width of=0A3.2mm compared with 9.8mm for the four rings.&nbs=
p; (For the oil=0Arings only the width contacting the cylinder bore is=
=0Ameasured)</span></p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb">&n=
bsp;</span></p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb">Since fric=
tion is in=0Aproportion to ring width (possibly due to the lower pressur=
e=0Arequired to make thinner rings seat against the cylinder wall) this=
=0Arepresents a reduction in losses to heat and a power increase=0A(smal=
l).</span></p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb"> </spa=
n></p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb">Another, much more=
=0Aexpensive, option for consideration. I also have no doubts=0Aab=
out the quality of the pistons, whereas I am not sure about the=0Afour o=
r five ringed replacements. They seem very cheap to=0Ame.</span></=
p>=0A<p class=3D"MsoNormal"><span lang=3D"en-gb"> </span></p>=0A<p=
class=3D"MsoNormal"><span lang=3D"en-gb">Ian</span></p>=0A</div>=0A</he=
aleys@autox.team.net></div></body></html>
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