In 1967, Tradeship/French Motor Company (in North California) had a new tool made of a new can of the same size as a Mabuchi FT16 with oval vent holes. These cans were nickel plated and were made from a folded flat sheet, not drawn like the Mabuchi or Champion cans. They offered it to George Mura but he declined. So they sold these cans to Cobra, Dyna-Rewind, and Certus amongst other companies, who used Tradeship endbells to make complete motors. So George got a bit iffy and went back to French and asked to have them produce the can for Mura but to modify the hole pattern so that there would be two round holes instead of one large oval. There was born the Mura "D" sized can, later nicknamed "A" after the "B" came out.
Mura had no magnets, so they purchased at first some Versitec SS101 mags and fitted them in a large, all-enclosing shim called "Can-in-a-Can". Then George went to work and had a new mold made for an all-new endbell, that was molded in black phenolic material, with the Mura name engraved on its nose (not to be confused with the Tradeship endbell used by Certus and others that has no name on its nose). These endbells used copies of Mabuchi hardware with flat brush-holder retainers and machined brush holders, but using copper as the material.
Once that was done, Mura issued the new motors with their own new armatures using new thinner laminations than what was available then except for the contemporary Champion 517. The motors were dark metallic green with black endbells and were available in four winding configurations. They signed up John Cukras and issued special versions of the motor with great two-tone faded paint in various colors, black/gold, silver/yellow, etc.
Bob Lenz also had his own version of this motor first in dark metallic blue then orange.
But all these motors did not have comm threads to hold the wires and they popped the wires that were simply soldered at the comm. So most fried while racing.
So George had a second generation of motors with new magnets made in the same molds but with better material and white (well, kind of cream color) endbells and new pent-roof copper brush holders. The Cukras line now came in solid colors: pink, white, and metallic purple. Eventually they figured out a comm welder similar to that of Dyna-Rewind, the true pioneer in such advances.
Later and after it was made obsolete, the D-size ("A") can motors received thinner shimless magnets and a FT26-size armature and were used for Group-12 racing and Dynamic and Riggen RTR cars. These were dark metallic blue with the white endbell. Cobra and Phaze III had their own versions in metallic maroon/purple. Dynamic also had a one-hole version of this motor in dark metallic green, this version being especially rare today.
Mura also sold the one-hole can to Nutley (dark maroon), Dave Bloom (silver or dark green), and Dart (orange) among others, as well as selling it themselves.
ALL, EVERY version of the above used the Mabuchi FT16D-size brushes. Don't let ANYONE tell you otherwise, it would be only tall BS. The first pros using such brushes did so only in mid-1969.
About that time, someone (I can't remember the name but I have it in my files) offered George a new lower can tooling that could take the Versitec magnets without a shim. George and Ron Mura first turned it down but then bought into it in late 1968. They made a new mold for the endbell and introduced a new brush-holder system using a copper plate and a "square" retaining plate for the still 16D-size brushes. This was the new "B" motor, with two smaller holes on the can. It was an absolute disaster, the motors running too hot and blowing on a regular basis. The Muras did everything they could to fix the problem: milled cans, vented cans, larger rectangular vent holes... but by mid-1969 they were in agony with this motor.
They also sold these motors and parts to Certus, Nutley, Bloom, Dart... none ever worked properly. The Brit pros heartily adopted it and used the things for over a year, but eventually reverted to more conventional motors after they found little advantage with the lower unit.
In the meantime, a fellow by the name of Bob Green had been making really good motors by cutting down Mura D-size ("A") cans on a jig fixture, fitting Champion Arco mags in them without shim, and machining down Mura end bells to fit. He was selling those motors to specialized raceways mostly in Louisiana and they were HOT. A new amateur racer by the name of Lee Gilbert, formerly running for Team Certus, was working with Bob and getting results. So George heard of it and hired Bob to design whole new can for Mura, patterned after the hand-built motor. A few months later, the "C" can was born. Champion quickly made their own version at about the same time, first as a folded can, then a thinner drawn version that was no good for anything.
But George had no magnets, so he sold only the can at first, then the can and a machined-down D-size endbell, then a complete kit with armature but no mags under the name "MPP" (Modified Production Products) with the names "Mura-Green-Gilbert" on the tags. But he could not make complete motors. So he approached Champion to buy some Arco magnets, but the GM there, an apparently disreputable fellow by the name of Ed Lewis, told him to go "screw himself", quote/unquote.
So Bob Green approached Bob Haines at REH and bought thousands of Arco "Blue Dots" magnets at wholesale prices, then had the dots sanded off. The mags were then assembled in complete motors by the likes of Arnie Atkins and Bob Green, now under full employment. Eventually, Champion sold the mags directly to Mura after Bob Rule had enough of Ed Lewis along with everyone else.
Eventually, all the remaining "A" and "B" motors and parts were liquidated in smart marketing ploys to the dwindling market, and the "C" can motors utterly dominated the market from 1971 to the 1990s, with Champion "C" motors used only sporadically by a few (but excellent) rewinders mostly on the East Coast (Joel Montague and his Pooch/Camen enterprise being by far the best).
This along with lots of color pictures is a whole chapter of the new book under construction.
So there!
please !
