When the Mabuchi brothers launched their FT16 and FT36 motors in 1963, they created a little revolution in the burgeoning slot car racing world. The new Mabuchi motors, while not being more powerful than the conventional, open-frame type motors previously used in model-train locomotives, manufactured by Pittman or other companies in the USA and Japan, were considerably lighter than the veritable boat anchors available until then. The difference was not in raw speed, but in cornering, where the lightweight simply smoked the cars fitted with the heavyweights.
As speeds slowly increased, as rewinds became more radical, heat became a serious factor. The Mabuchi endbells, made of Delrin, had a fairly low melting point. Generally speaking, what was happening under stress and the very unclean power of many tracks using a battery charger to feed the lanes, was a slow melting of the endbells, moving the brush holders, causing the brush springs to melt into their posts and eventually causing the most dramatically spectacular failures, as well as terribly smelly ones.
The first attempts to address this was the fitment of metal sleeves over the spring posts, that helped the springs to keep their composure. The first know commercial examples of these were seen on the Dyna-Rewind motors concocted by motor genius and GM engineer Ted Lech. It will take a full year for the "major" motor rewinders, Mura and Champion, to catch up with those details. However this did not stop the endbells from melting.
Nest step was the very intelligent design of a completely new endbell for their "700" series motors (the BIG Mabuchi FT36D) by Champion of Chamblee. The brush holders used pent-roof "hats" to keep them in place, and the design worked well enough, for a while, but even the Cycolac plastic eventually melted. A similar endbell was introduced in 1967 for their "500" series of rewinds.
Meanwhile by early 1968, the folks at Mura had made a new endbell mold and produced them in a gray plastic that was more heat resistant, but still melted under the stress of bigger armature wire, now up to 25 AWG. Later that year, a revision of the failing motors produced the first phenolic plastic endbell, the famous "Mura-Cukras" motors now benefiting of the design also featuring the Champion style pent-roof design.
Competition was now fierce between the two companies, and by September 1968, Champion produced their response to the new Mura M400-series motors in the form of the "535" and "545" series of new motors. These came in plain black, or as "Bob Cozine Signature" specials designed to counter the "John Cukras" signed motors offered by Mura.
These new Champion motors had a new phenolic plastic endbell, one that is quite scarce today. It was supplied to the Champion folks by a company called United Commercial Co., a manufacturers representative in Japan. I recently analyzed an unused sample, called "EB-1", now at the LASCM.
I always knew that this was the first commercially available, Mabuchi-size endbell using machine screws instead of the self-tapping kind, to hold the brush holders and other ancillaries to the endbell.
Amazingly, I found something that escaped me in the past, than this endbell is fitted with threaded metal inserts in no less than FOUR places on two planes, as well as an armature bearing insert! I always thought that the machine screws were simply bolted directly to the plastic.
One has to understand that until this time, all Mabuchi and clones endbells used self-tapping screws to hold their brush holders and to attach the motor to the rear-axle bracket. That in turn, caused a deformation of the endbell and some misalignment of the armature bearing and brush holders, not something one wants to have on a top-flight motor.
The new endbell addressed all these concerns, as each plated brass insert was first hand fitted inside the mold, than the black plastic was injected around the inserts. In other words, a very costly process that required lots of operator skill and time. But what a beautiful product!
Below are pictures of the only two motors that used the "magic" endbell, the Champion "535" and "Bob Cozine Signature" motors:
I do not know another example in the whole slot car racing history of such an elaborate plastic endbell... for me, it represents the finest of Champion's 1960s products, when the motor situation came to at last, provide stability and reliability in the product, instead of the regular hand grenades used until then. The next step would be the smaller C-can, a revolution in itself.
The separate sintered bronze bushing fits inside a plated brass insert itself molded directly in the plastic.
All the mounting points including the can to endbell tiny 0-80 mounts receive a plated brass insert!
The two endbell to rear-axle bracket mounting points also receive threaded inserts, causing no bearing or brush holder misalignment, previously experienced with self-tapping screws.
Shortly after these now scarce pieces were issued, Champion had new tooling made for yet another new endbell, that unfortunately went backwards, using a brass plate on which the armature bearing was soldered, screwed onto the endbell with self-tapping screws. The molding was too thin in the threaded area, causing the self-tapping screws to quickly pull the threads. This was the famous "Orange Picker" endbell, that will be inflicted on all new Champion production "16D" sized motors until the advent of the C-can.
Why did Champion abandon such a great endbell to replace it by something less than satisfactory? The only reasonable explanation would be to reduce manufacturing costs. But what a shame! In fact in many ways, the PREVIOUS Cycolac endbell used in the "507-R", "517" and "525" motors was a much better enbbell, one that only needed to be made of more heat-resistant plastic to be an excellent replacement. It was not to be....
