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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple style='word-wrap:break-word'><div class=WordSection1><p class=MsoNormal>Mirek:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>My experience: When my BJ8 engine was rebuilt the first time in 1985 (at approx. 140k miles, 40k or so by me), 5 ring pistons were used (.030 over). I vaguely remember being told at the time that the factory used these pistons in their truck and marine engines – something about reduced piston slap for less wear, and maybe a bit more friction, but nothing really important in a stock big Healey engine for the street. In any case, that was what was available at the time, so that’s what went in.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Fast forward another approx. 140k miles to the recent second total rebuild, this time all miles driven by me, and with really good hobby car maintenance by me – a bit of overkill if anything. The engine was in really good shape when taken apart – didn’t really need to be done quite yet, but we were doing a total ground up resto on the car, so now was the time. ( I just might be the only big Healey owner that has run an entire rebuild cycle with 5 – ring pistons and then had the engine apart again and had a look).<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>New 5 – ring pistons were chosen – again all we could get in .040 over – and again, the engine was done to stock specs – ignition, cam, carbs etc. all as original. After some ‘sorting’, the engine has now approx. 15k miles on the new rebuild, and is running beautifully – excellent power for a stock spec engine. Approaching 300k miles. Amazing!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>As an aside, at the first rebuild in 1985, 12 hardened valve seat inserts were installed in the head – 2 adjacent ports had cracks, and at the time the world was faced with the unleaded fuel changeover. At this recent rebuild, the head barely needed work, a valve grind and not much else after being run exclusively on unleaded fuel for that entire rebuild cycle. ( didn’t even have hardened exhaust valves – couldn’t find any at the time). Sintered bronze guides too – we didn’t know any better! They must have been fitted right, they were left as is at the 2<sup>nd</sup> rebuild. Normal o-ring valve stem seals were used again – no unusual oil consumption at this time. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Based on my experience, unless you are modifying the engine for more power and therefore might not want the slight extra friction, I would install the rings. There is no question that the piston skirt is better supported with the extra ring below the pin, and the groove is already there – also, there is the possibility that there could be a down side in the long term from running with the groove empty. I doubt that anyone has enough mileage on such a rebuild to say for certain that it will be trouble free.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hope my experience helps with your decision.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Earl Kagna<o:p></o:p></p><p class=MsoNormal>Victoria BC<o:p></o:p></p><p class=MsoNormal>BJ8, BT7 tri-carb<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal> <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b>From:</b> Healeys <healeys-bounces@autox.team.net> <b>On Behalf Of </b>m.g.sharp--- via Healeys<br><b>Sent:</b> Friday, April 16, 2021 10:35 AM<br><b>To:</b> healeys@autox.team.net<br><b>Subject:</b> [Healeys] To fit or not to fit - that is the question: apologies to Hamlet<o:p></o:p></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Hi all,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>More on the rebuild of my BT7 engine. A number of years ago I purchased +0.030” AE pistons in anticipation of this rebuild. The AE <span lang=EN-CA>pistons have 5 rings: 3 compression and one oil control above the wrist pin and one oil control lower on the skirt, below the gudgeon pin. The pistons that came out, which were the originals, had the conventional 3 compression rings and one oil control ring.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA>I am wondering about that second oil control ring below the gudgeon pin and whether I should fit it or not. I am not building a performance engine, just want the highest quality job possible. The original pistons functioned fine and I never had oil consumption issues in the 110,000 miles I put on them. This engine had a bit of piston slap, which was typical of them. I wondered if the extra ring lower on the skirt was to address this. Perhaps it was a complaint from Austin Westminster owners wanting quieter engines? Was the 5<sup>th</sup> ring for another application? I also wonder whether wiping the oil off the bores by the lower control ring is a good thing or whether it is better to have some cylinder wall lubrication from oil splashing onto the cylinder walls.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA>I have searched for a service sheet on these pistons (thanks Scott!!) but found nothing. I also searched the List Archives, and there are a few older postings that suggest fitting all 5 rings, but no reasons why.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA>I doubt we can really know what is going on in there as the dynamics are complex, but I would be interested in any experience anyone has had with the 5-ring pistons. Theoretical discussion is always welcome!<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-CA>Best, Mirek<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-CA><o:p> </o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div><div id="DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2">
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