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We use them in every S65 build that does not have a Dailey Engineering dry sump system. Our most recent experience is that every S65 we see with a spun No. 1 main bearing and/or spun rod bearings has had aftermarket rod bearings installed with larger clearances within 10k miles or so. As BE's analysis candidly admits, the larger clearances do reduce oil pressure by a not immaterial amount, and our view is that the vanos system lacking its own pressurization system periodically exacerbates this phenomenon and increases the deficiency, causing a further drop in oil pressure. Combined with the S65s tight clearances, particularly on the No. 1 main bearing, where the journal expands when the harmonic balance bolts are installed, one winds up with an insufficient oil wedge. Increasing oil pump output by 20% plus with the SRD gears is in our view the best means of addressing the issue prophylactically short of installing a Dailey. And at $400, they are a tad more economically feasible than a Dailey. We are engine dynoing one of our S65 strokers that has the SRD gears installed tomorrow and Tuesday and will report back on the oil pressure analysis. Our clearances all exceed 0022" so it will be interesting to see.
Be well, and go fast.
--Peter
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