I am by no means disparaging using a roller bearing. I just want the potential issue with using a roller bearing to be clear to anyone reading this now or down the road. The difference is that all those systems you mention were DESIGNED to use a roller bearing. The Cub mechanism was DESIGNED for the graphite. Keep in mind a Cub was originally designed to be inexpensive and last seven (not seventy!) years. There are several "corners cut" that could have been engineered differently. One being the TOB mechanism, no use spending the time, money, and engineering to make it always perfectly centered with a more complicated mechanism when IH could use a graphite block and some flat strap metal bolted together and aligment of the TOB to clutch fingers can have a little offset and fully function without harm.Fireman Bob wrote:.............I am not disparaging the graphite system but almost every clutch throwout system in the last 50 years has used a roller bearing with great success.
I hope they do tolerate it but put two pieces of metal together with no lubrication and move them back and forth at a rate of 1800 times a minute. If the TOB is not centered every time the engine makes one revolution the clutch fingers have slid out and then back on the face of the roller bearing. Longevity of the roller bearing really depends on how often you use the clutch, how far the fingers slide, and how fast the engine is turning. If clutching infrequently the fingers and TOB could cool off between clutching. If clutching more frequently, the fingers and TOB may heat up and be able to tolerate it, but it can't be doing the grease and seals in the roller TOB any good.Fireman Bob wrote:........
While there will be some lateral/radial movement between the clutch fingers and the bearing if everything is not centered both of these surfaces are hardened to over Rockwell 55 and should easily tolerate this.........