I read this tech rag when I'm on the crapper at work:
August 2002 Mechanical Engineering Departments: News and Notes
Clip from the article:
A custom injection molder in Cincinnati has developed a polymer distributor gear that the company said can provide longer life even under harsh racing conditions.
The company, Performance Plastics Ltd., worked with Victrex USA Inc. of Greenville, S.C., to develop the gear's material, a proprietary polyetheretherketone polymer. Frank Mills, the company's national sales manager, claimed that key advantages of PEEK are wear resistance and light weight. The material can withstand continuous operating temperatures of 500°F and retains physical properties close to its melting temperature of 645°F, according to Victrex. Mills also noted that the PEEK gear is more than 80 percent lighter than a bronze alloy gear.
PEEK distributor gears are said to be 80 times lighter than conventional bronze alloy gears.
Mel Perry, the owner of Mel's Ig-nition, a manufacturer of custom-made distributors in Siler City, N.C., has tested the gear.
Conventional metal gears may need to be replaced after 700 to 800 laps. The PEEK polymer gears are wearing more than five times longer, which can mean that they'll last for an entire racing season, Perry said.
"When you are turning 7,000, 8,000, 9,000 rpm, you are stressing everything beyond their capabilities," he said. "This composite gear runs cool, and that cooling leads to less friction and wear and longevity."
Mills said that the gears could be molded to the same dimensional tolerances as bronze alloy gears. His company keeps an inventory of standard sizes, and Mills said that the gears could also be supplied oversized, which some racers believe can reduce backlash and increase horsepower.
Performance Plastics is producing PEEK gears for Ford, Chevrolet, and Chrysler engines. The first gear went into service at the end of 2001, and to Mills's knowledge none has been replaced.
