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MBruns MBruns is online now
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Join Date: Oct 2003
Location: Central Fla
Posts: 1,687
pin fit

Andy, it is common practice in performance engines to pin fit and set clearance in both rod bushings and piston pin bosses, they are floating pins by design, and need room for an oil film to reduce wear, prevent distress etc.. every piston has some way to get oil to the pin via oil ring feed or broaching the pin boss. On alot of OEM production engines they have press fit/floating because its cheaper. On some engines where you run hi vaccum and or dry sump there is a need for DLC coatings on the pins, even extra clearance. We never run them tighter than .0006 in. and always check them. In severe use we have found that they stay in spec much longer if they start out with proper clearance.

Mike Bruns JBRacing.com
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Old 09-09-2010, 09:13 PM
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