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<div dir="ltr" data-setdir="false"><div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;" data-setdir="false">Hey Ian,</div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;" data-setdir="false">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;" data-setdir="false"><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;" data-setdir="false">Bill Atterbury</div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;" data-setdir="false">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 href="mailto:rianhey@btinternet.com" style="color: rgb(25, 106, 212); text-decoration-line: underline;" rel="nofollow" target="_blank">rianhey@btinternet.com</a>><br></div><div dir="ltr" style="font-family: Helvetica Neue, Helvetica, Arial, sans-serif;">To: <<a href="mailto:healeys@autox.team.net" style="color: rgb(25, 106, 212); text-decoration-line: underline;" rel="nofollow" target="_blank">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: <002201d732eb$915662a0$b40327e0$@btinternet.com><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. (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></body></html>