These examples of failed retainers, except the piece on the far right, are typical when engine rpm's exceed 32,000 for extended periods of time. Materials used & tested include beryllium copper (full hard # 172), A-2 tool steel (Rc-60), & C-350 maraging steel (RC-62). The piece on the right made of (C-350) maraging steel, has been tested many times at 32,000+ rpm's without wear or failure using oil contents of 6 to 8%. The retainer's OD is guided in the connecting rod's ID with .001 clearance. Also notice the wide window in this retainer which accepts two side by side rollers. This increased the load carrying ability & the wear resistance of the assembly greatly. There is no problem with the two rollers rubbing against each other as thought by some engine builders! The retainer is necessary at high rpm to prevent the rollers from developing a "helix angle" common with all uncaged assemblies. This problem with uncaged assemblies in high speed applications causes high friction, high heat & eventual failure.
