BUSA RIDER Posted January 15, 2012 Report Posted January 15, 2012 hi all new to the site happen to b doing a top end rebuild with mild port and stock head mod anybody know what the piston to wall clearance should b on wiseco 64.5 mm pro lites thanks in advance for any help wiseco tech is reccomending .003 BUSA rider Quote
BigRed350x Posted January 16, 2012 Report Posted January 16, 2012 Are you using a bore gauge and calipers? Using a feeler gauge is not the best way to measure ptw clearance. The reason you need a micrometer and bore gauge is because the piston is different in size at different points of the piston. Wiseco will give you a location on the piston to measure, like 1.300" down from the ring groove, 90deg away from the wristpin (or something similar) this is the point where you need to measure the piston, then measure your bore (hope your bore is true throughout). Take the difference and divide by two. This is how I was taught to do it when I was working at PRS Machine Works. You can do it with feeler gauges, but its not as reliable as using a bore gauge and calipers. Quote
mike0chek Posted January 16, 2012 Report Posted January 16, 2012 Are you using a bore gauge and calipers? Using a feeler gauge is not the best way to measure ptw clearance. The reason you need a micrometer and bore gauge is because the piston is different in size at different points of the piston. Wiseco will give you a location on the piston to measure, like 1.300" down from the ring groove, 90deg away from the wristpin (or something similar) this is the point where you need to measure the piston, then measure your bore (hope your bore is true throughout). Take the difference and divide by two. This is how I was taught to do it when I was working at PRS Machine Works. You can do it with feeler gauges, but its not as reliable as using a bore gauge and calipers. so would you get a larger reading with a feeler then the bore gauge, or othe other way around? Quote
BigRed350x Posted January 16, 2012 Report Posted January 16, 2012 so would you get a larger reading with a feeler then the bore gauge, or othe other way around? LOL I don't know, I wouldn't do it with feeler gauges. LOL You will get a sloppy reading. Using a flat tool to measure two round surfaces... Quote
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