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Feature
DRAG RACING ENGINE BUILDING TIPS
Left: Roller cam bearings are a plus in a race engine for a couple of reasons. They can handle very high valve spring pressures better than plain bearings, and they help reduce power-robbing friction. Top right: Main bearing clearance is checked by bolting the caps to 100 ft.lbs. with the bearings installed, then measuring with a dial bore gauge. Bottom right: The cap on this connecting rod for a 565 sportsman engine is torqued to 95 foot-pounds. A bore gauge to measure bearing clearance is then used and the coated bearings are set to .0025˝-.0032˝ clearance . The rods are forged from 4340 steel alloy that has a compact, uniform grain structure for ultimate strength. The wrist pin and big end bores are honed to a +/-.0002˝. tolerance, and the wrist pins have bronze alloy bushings. (Photos courtesy of Atech Motorsports)
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