Martex was a small Midwestern commpany out of Detroit, mainly known for tire traction and other chemical products. The actual name was Scale Model Cars Co., using the brand name Martex (just saw that in a Preview page from Car Model in November 1965). Pete Hagenbuch also talked a lot about their tire traction, which seems to have been popular around Detroit.
But a couple years ago on ebay, I found a car with this Martex 16D motor, based on a later-generation Mabuchi, with an inner magnet shim. Finally tried it out a year ago on the Bordo track and it was a rocket ship! High revs and good torque... finished second in a "vintage" race behind a retro car one of the locals was trying out... (it's kind of a run what ya brung vintage race, with any kind of running gear but older bodies).
So, I ran it again this year - but after five or so segments, running very strong, it didn't start for the next one - all locked up, but didn't seem to have burned out, and couldn't see anything apparent... When I got it home, I took it out and this is what I found:
A closer look at the endbell revealed the culprit - the endbell, where the brush holders had melted into the plastic:
Fortunately, the arm wasn't harmed; can't quite tell what wire is used, maybe 28, and the balancing holes, tho not the epoxy, are very Dyna-like...
Since the endbell was totally stock, I was able to replace it, with a new bagged Mura in this case (original Mabuchi, not a hi-temp version):
And it will now be retired - I got lucky! Maybe not such a good idea running this in the first place, but since it surviced eight 3-minute heats last year, I figured what the heck - and it was fun driving that hot a motor!
Anybody else got any Martex products?