- Joined
- Nov 26, 2009
- Messages
- 3,157
The pins in the photo below are from Kenny's racer after a few wins up to the point where he broke his crank. You can see that the coated pins and internal small rod end surfaces are in perfect shape with no wear whatsoever. The small ends of the rods show oil stain only - there is no evidence of metal to metal contact. So who needs bronze bushings? - Its just dead weight.
The crank had already suffered fatigue from several racing seasons with heavy, bronze bushed Steel rods and standard/full weight racing pistons before switching out to the recently available lightweight JS pistons & rods. The violence and stresses caused by the shaking forces increases exponentially with RPM. Reducing piston & upper rod weight helps to avoid or at least postpone expensive crankshaft destruction.
http://www.jsmotorsport.com
Jim Schmidt
The crank had already suffered fatigue from several racing seasons with heavy, bronze bushed Steel rods and standard/full weight racing pistons before switching out to the recently available lightweight JS pistons & rods. The violence and stresses caused by the shaking forces increases exponentially with RPM. Reducing piston & upper rod weight helps to avoid or at least postpone expensive crankshaft destruction.
http://www.jsmotorsport.com
Jim Schmidt