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Hey Ian,The rumor I heard was that the 5th ring was for hone-and-replace r=
ebuilds to reduce oil consumption.=C2=A0 I'll let others comment if these c=
ars were fitted with 4 or 5 rings from the factory (I'm guessing 4).=C2=A0 =
I rebuilt mine with 4, like the others.=C2=A0 Not a problem for our coddled=
Healeys.=C2=A0 Heck, I even know of one fellow who only put in three for a=
hot motor.
Bill AtterburyBT7
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Message: 1
Date: Fri, 16 Apr 2021 19:08:56 +0100
From: "Ian Hey" <rianhey@btinternet.com>
To: <healeys@autox.team.net>
Subject: [Healeys] To fit or not to fit
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.=C2=A0 These have three rings with =
a
total width of 3.2mm compared with 9.8mm for the four rings.=C2=A0 (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) thi=
s
represents a reduction in losses to heat and a power increase (small).
Another, much more expensive, option for consideration.=C2=A0 I also have n=
o
doubts about the quality of the pistons, whereas I am not sure about the
four or five ringed replacements.=C2=A0 They seem very cheap to me.
Ian
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<html><head></head><body><div class=3D"ydpf5e37345yahoo-style-wrap" style=
=3D"font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px=
;"><div></div>
<div dir=3D"ltr" data-setdir=3D"false"><div><div dir=3D"ltr" style=
=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;" data-setdir=
=3D"false">Hey Ian,</div><div dir=3D"ltr" style=3D"font-family: Helvetica N=
eue, Helvetica, Arial, sans-serif;" data-setdir=3D"false">The rumor I heard=
was that the 5th ring was for hone-and-replace rebuilds to reduce oil cons=
umption. 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, lik=
e the others. Not a problem for our coddled Healeys. Heck, I ev=
en know of one fellow who only put in three for a hot motor.</div><div dir=
=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif=
;" data-setdir=3D"false"><br></div><div dir=3D"ltr" style=3D"font-family: H=
elvetica Neue, Helvetica, Arial, sans-serif;" data-setdir=3D"false">Bill At=
terbury</div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helveti=
ca, Arial, sans-serif;" data-setdir=3D"false">BT7</div><div dir=3D"ltr" sty=
le=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><br></div=
><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, s=
ans-serif;">---------------------------------------------------------------=
-------<br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Hel=
vetica, Arial, sans-serif;"><br></div><div dir=3D"ltr" style=3D"font-family=
: Helvetica Neue, Helvetica, Arial, sans-serif;">Message: 1<br></div><div d=
ir=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-ser=
if;">Date: Fri, 16 Apr 2021 19:08:56 +0100<br></div><div dir=3D"ltr" style=
=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">From: "Ian =
Hey" <<a href=3D"mailto:rianhey@btinternet.com"; style=3D"color: rgb(25, =
106, 212); text-decoration-line: underline;" rel=3D"nofollow" target=3D"_bl=
ank">rianhey@btinternet.com</a>><br></div><div dir=3D"ltr" style=3D"font=
-family: Helvetica Neue, Helvetica, Arial, sans-serif;">To: <<a href=3D"=
mailto:healeys@autox.team.net"; style=3D"color: rgb(25, 106, 212); text-deco=
ration-line: underline;" rel=3D"nofollow" target=3D"_blank">healeys@autox.t=
eam.net</a>><br></div><div dir=3D"ltr" style=3D"font-family: Helvetica N=
eue, Helvetica, Arial, sans-serif;">Subject: [Healeys] To fit or not to fit=
<br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica,=
Arial, sans-serif;">Message-ID: <002201d732eb$915662a0$b40327e0$@btinte=
rnet.com><br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue=
, Helvetica, Arial, sans-serif;">Content-Type: text/plain; charset=3D"us-as=
cii"<br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helvet=
ica, Arial, sans-serif;"><br></div><div dir=3D"ltr" style=3D"font-family: H=
elvetica Neue, Helvetica, Arial, sans-serif;">In a recent engine rebuild of=
a standard BJ7 engine which was fitted with<br></div><div dir=3D"ltr" styl=
e=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">four ring =
pistons, when I looked at replacement pistons they were pictured<br></div><=
div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, san=
s-serif;">with five rings, which did not seem good to me.<br></div><div dir=
=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif=
;"><br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helveti=
ca, Arial, sans-serif;">I fitted Omega pistons from Denis Welch. Thes=
e have three rings with a<br></div><div dir=3D"ltr" style=3D"font-family: H=
elvetica Neue, Helvetica, Arial, sans-serif;">total width of 3.2mm compared=
with 9.8mm for the four rings. (For the oil<br></div><div dir=3D"ltr=
" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">ring=
s only the width contacting the cylinder bore is measured</div><div dir=3D"=
ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;"><=
br></div><div dir=3D"ltr" style=3D"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=3D"ltr" style=3D"font-family: Helvetica=
Neue, Helvetica, Arial, sans-serif;">pressure required to make thinner rin=
gs seat against the cylinder wall) this<br></div><div dir=3D"ltr" style=3D"=
font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">represents a re=
duction in losses to heat and a power increase (small).<br></div><div dir=
=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif=
;"><br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helveti=
ca, Arial, sans-serif;">Another, much more expensive, option for considerat=
ion. I also have no<br></div><div dir=3D"ltr" style=3D"font-family: H=
elvetica Neue, Helvetica, Arial, sans-serif;">doubts about the quality of t=
he pistons, whereas I am not sure about the<br></div><div dir=3D"ltr" style=
=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">four or fiv=
e ringed replacements. They seem very cheap to me.<br></div><div dir=
=3D"ltr" style=3D"font-family: Helvetica Neue, Helvetica, Arial, sans-serif=
;"><br></div><div dir=3D"ltr" style=3D"font-family: Helvetica Neue, Helveti=
ca, Arial, sans-serif;">Ian</div></div><br></div></div></body></html>
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