Leading valve train specialist Kibblewhite Precision Machining is offering a choice of three different material specification valve guide seals for most Harley-Davidson applications, including Panheads, Shovelheads, Ironhead Sportsters, Evolution Big Twins, Evolution style Sportsters, and Twin Cams.
Their “PC Style” Valve Stem Seals for all Harleys (except V-Rods) are made in PTFE (Polytetrafluoroethylene), a synthetic fluoropolymer of tetrafluoroethylene. PTFE does not have “memory” and therefore is subject to "creep", which allows the seal to conform to mating surfaces - which controls oil without letting parts run dry.
KPMI say they have used fillers to keep the material stable and to reduce friction; PTFE is known to retain its mechanical properties at temperatures as high as 500°F. The twin spring design provides continuous tension on the valve guide and the stem of the valve.
KPMI's steel clad OE style seals have a low profile for seal-to-retainer clearance, and will fit inside dual spring assemblies. Also made in PTFE, they incorporate a special low friction graphite impregnated sealing element.
Finally, KPMI's solid and steel clad Viton valve stem seals are designed to have "optimum fitment, allow for maximum lift, and to give maximum life," according to CEO Will Kibblewhite."Our Red valve stem seals are resistant to high temperatures, petroleum products and the corrosive gasses that are the by-products of combustion. These seals retain their ability to seal in situations where other materials could harden and allow oil to enter the combustion chamber causing detonation, carbon build up and a loss of power. The Red Ones are truly the racer’s choice!"
KIBBLEWHITE PRECISION MACHINING INC
www.kpmi.us