18 replies to this topic

[Junior8]

I'm seeing 8-10 and 12 volt Kemtrons motors listed on ebay and for the life of me I can't recall using anything but 12 volt motors on the commercial tracks that we raced on back in the late sixties. Even the old pittmans wre 12 volts I believe. Will these lower voltage 8-10 volt motors run on a pyramid ps26kx power supply without going up in smoke. I have an old pittman 196B that I can't find gears for and it runs fine on my track. If I could find the gears for this thing I would bild a car around it. The axle carrier as everyone knows is very narrow and meant for bevel gears and I have found crown gears but no pinions for it. I would love to build some vintage type cars with the dinosaurs. If anyone has a pinion and crown gear that will give me a 3 to 1 ratio please let me know.

[Larry LS]

Those old Pittman motors are tough old birds. Back then they came around here at least in varied voltage ratings which were. low end ratings we found. The 12volts would run on up to 24 volts in some of the dragsters The 8 and 6 volts were fine on 12-15 volts.

I re-wound many Pittman 706 and DC65x and 196B arms to what I called four volts. They were faster but still reliable for even enduros.We ran some as many as 52 hours, 24 hours and many 12 and 6 hour enduros locally. Never had one blow without someone doing something real bad to them. I still have several of these left that still run fine almost 40 years later.

The one 706 I have is a survivor from our 52 hour enduro and still runs nice and strong. The other two were given away to team members after the enduro. Each ran at least 1/3 of the enduro before they were replaced for new brushes and wheels and tires on them.

Good old motors.

:mrgreen:

[Junior8]

Cool! Thanks for the info. Now can you tell me approximately when pittman bought out Ram motors and the rams were sold as pittmans thereafter I believe. I'm mainly interested in a Ram 426A and from what I understand the rams actually had no identifying marks on them.

[slotbaker]

Bill, Have you tried Pattos Place for the bevel gears.
Scroll down on the left to "Gears & Bearings".
The bevel crown & pinions only come as a set.

[Larry LS]

The Ram motors were never Pittmans as far as I ever knew.

They were copies and were basically hot rodded Pittman look a likes . I have used them as well and had their 7 pole version copy of a Pittman DC85. You could tell the diference by looking at them side by side for sure.

Then there was another Ram similar motor they made like the 705 but with a three pole armature.

There was another Ram motor also but it escapes my memory right now.

[Horsepower]

The Ram 711 looks just like a Pittman 196.

[edworth]

The axle carrier as everyone knows is very narrow and meant for bevel gears

I know it isn't desirable but grinding the insides of the carrier may get enough space for modern gears... Also other rear carriers may from time to time be found... even then space is at a premium.

Those old Pittman motors are tough old birds...I re-wound many Pittman 706 and DC65x and 196B arms to what I called four volts...
Good old motors.
:mrgreen:

Are you still rewinding stuff?

I have a hankering to set up a fast 706 or two. And a 4v arm seems like the ticket. Are you still up to it?

[Prof. Fate]

Hi

The "voltage ratings" were mostly trying to indicate the hotter winds. No real basis in reality. I didn't run these motors in the day. I saw my first commercial track and 36ds in the same time and always ran cans (March '64).

The racers I knew running them would run the 6 volt and 8 volt "padlock" style motors, the DC85 types for "roadracing" in the cases I saw. The only ones showing more concern were the drag racers who would dial up to 24 and 36 volts. But I never did the drag racing.

For the 704/5/6 type pittmans. These were popular in '63 when I returned stateside even in 1/32 home racing circles (though the whole 1/16th clearence thing was gone!). I have a couple old 1/24s from that period that were originally home cars, ran briefly at the commerical tracks and were retired. My Cans were so much faster.

One mystery for me is that one of the survivors has a RAM in it, but I don't remember BUYING a ram. I don't even remember it being available when I was running these cars. Iwell, I think it is a RAM!....?)

I did buy one of the RAM clones of the DC196 for 1/32 club racing.

I have a bunch of the 196bs which, in the day, were rated at "8volts". After 40 years of running, they are still......errr, running. Always on a nominal 12 volts (13.4). I have never "lost" one.

I like keeping my old cars running, Pittmans seem to require NO maintaince if stock.

Prof.Fate

[idare2bdul]

I have a hankering to set up a fast 706 or two. And a 4v arm seems like the ticket. Are you still up to it?

So how fast do you want to go? i've seen this style of motor with a cobalt magnet and a group 15 arm. Yeeehawww! If you tell me it isn't vintage, tell me you would not have run it back then if you had one. This car might show up at the convention with it's mystery owner..

[Robert Livingston]

The most common Kemtron was the X-503-8, wound for 8 volts, but always run on the 12-18 volts found on the tracks of the day. The heyday of the X-503-8 was about 1964-5. I believe they are marked on the brass ends as to motor voltage. There were lower and higher voltages available, but the 8-volt was the common one.

Pittman's motors were wound to deliver a certain amount of power (revs and torque) at a specific voltage. 12 was a common nominal voltage, given the prevalence of automotive batteries which produce 12 volts, and their chargers which put out around 13 and a half. Most HO model railroads ran 12 volts, while the bigger O scale layouts ran 16 or so, often AC, with rectifiers in the locomotives which converted the AC to DC and knocked the volts down to 12. So 12 it was, a de-facto standard for slot cars, based as they were on model locomotive motors and power supplies. The Kemtrons were actually engineered to fit inside Diesel locomotive models, as were the Pittman 703's and their successors. The inline types (DC 60, 62, 195, 70, etc.) were designed to fit inside steam locomotive boilers.

When people wanted to go faster, Pittman distributed some 6 volt winds which were quite satisfying on 12 volts, thus the birth of the "six volt" armature and myth. A hotter wind could be called 4 volts or less, but it really was intended to function on 12 or so volts. The nominal standard of 12 volts across the rails was often quite a bit higher, in reality.

The Pittman DC 196B was sold as an 8 volt wind, while the DC-65X armature (which was used by Howie Ursaner and his buddies so successfully, as well as the Hagenbuch/Wallingford/Dobson crowd) was nominally 6 volts.

One of the old-time motors (say, 1963-4) wound for low volts, but used on higher voltage slot tracks, was the 4 volt Bonner, an erstwhile model aircraft servo motor. By todays standards, or even 1965, not a fast motor, but "4 volts" it was.

When people started rewinding motors (c. 1965), we started forgetting about voltage ratings and went as hot as we could, without losing too much longevity or drivability. It use to be that anything under 2.0 ohms winding resistance was considered hot; this dwindled to a tenth of an ohm or less, as the commercial raceways were built and other car factors (like glue on the track) allowed higher and higher motor output, and increasing car speed. But I don't know much about that.

[idare2bdul]

One of the old-time motors (say, 1963-4) wound for low volts, but used on higher voltage slot tracks, was the 4 volt Bonner, an erstwhile model aircraft servo motor. By todays standards, or even 1965, not a fast motor, but "4 volts" it was.

The worst motor i ever owned, but at least no series mandated I use them like FK's.

[TSR]

That's the thing: you don't have to race the series if you don't like the motors...

[Larry LS]

Edworth; in a word No, I don't rewind the old Pittman motors anymore.

I have lost all my old data from back then as to what I used etc.

I still do have some of the good double polythermalese coated #30 wire I used back then.

Dewinding them was the real chore as I never did find any blank Pittman arms to do.

I had a small desk I worked at in the living room back then that I worked at. I would be sitting there counting turns on an arm and the wife would ask a question sometimes, as I did it in my head and was quiet. So all I had to do was start counting out loud and she would say " excuse me" as she figured out what I was doing.

One way to keep it quiet around our house. Just as long as I did not do it too long, one arm a night was enough to keep me out of trouble. :roll:

[hiline2]

Back to Kemtrons, were they just as good in dragracing as the pittmans? if not why ??

Ive got both pittman 85s and 65s and some Mustang Kentrons Im looking ot have fun with !

[Tex]

If anyone has a pinion and crown gear that will give me a 3 to 1 ratio please let me know.

I was given some gears that came from the distributor REHco. The brand is "American Line" and the part number is "BEV-310". The package includes a 12-tooth beveled pinion and a 36-tooth beveled crown gear, both brass. However......... it looks like both the crown gear AND the pinion fit a 1/8" shaft. Maybe you could "sleeve" the pinion(?).

[idare2bdul]

Why weren't Kemtrons used for drag racing? Drag racing was done by class and different class cars ran on different voltages from 18 volts to 36 volts.

While you saw guys run Kemtron powered cars for fun with a variety of body styles I can't remember anybody getting them to live on 24 volts, which we ran gassers at and 36 volts for Dragsters was likely well beyond their ability to survive. I wasn't into hopping up motors back then but as an educated guess I would point to the commutator as a likely culprit. On 24 volts the Pittmans and Rams were the bulk of most fields. None of these motors had much in the way of magnets by modern standards.

Most of what you read about today is the dragsters, either the kit based or hand made magwinders but I always liked the gassers with their scale body's and scale like performance, launching with a wheelie and spinning the wheels for much of the run.

[don.siegel]

Actually, by 1965 or so, the Ram DC850 then 857 had totally replaced the big Pittman; when you look at the period reports, nobody was running Pittmans anymore! And I don't think I ever saw a Kemtron being entered, supposedly for reasons of reliability, as mentioned above; besides the commutator, the little round brushes and coil springs may have been a weak point, especially on 24 volts or higher. They were made in Japan and "designed to a price" as one says - about a buck or two cheaper than the Pittmans and Rams...

There were a few rewound Mabuchis entered in these races, mostly the national mail-in events, but I don't think I ever saw one in a California drag event, at least not in the magazine reports.

One year, a mail-in entry from England won the 1/32 class in the Car Model national drags, and he used a rewound Milliperm! (a German made hobby motor popular in England: Microperm, Milliperm and Monoperm models). The winner also wrote a letter in a subsequent issue, kind of balling out the Americans for always wanting to use such high voltages, instead of tuning their cars! I think there was also a hint of everybody playing follow the leader, with the big Ram motors in just about every class...

I think John Cukras was an early winner in drag meets before going to road racing, and so was Sandy Gross back East - with a very neat Monogram based Mabuchi rewind if I remember correctly. Sandy - are you tuned in? any memories?

Don

[Prof. Fate]

Hi

When I went to Salt Lake in late 65, there were NO cans running in any class, road or drag. Everyone ran the big pittmans and Kemtrons. I have an old friend who was an older married adult with kids in '65 and still waxes nostalgic over Kemtrons.

On the other hand, after 704 types on a small club track, I never ran the big "padlock" motors! First 36ds rewouund then smaller.

Anyway, in '65, the locals were tracking every race held in the state, some 20 raceways in a state with a million people. And everyone ran the padlocks. Between late August and the end of Season, december 1, I won so many races I was 4th overall in the state for the year. With a 36d sidewinder.

By the end of the year, the padlocks had pretty much disappeared.

Anyway, in the mid 90s I was racing at the local track and this guy shows up, stares at me and says "You must be rocky?" Ya... The story was that he had won races with his kemtron before I showed up with cans. He could never make the can work, quit racing...and wondered what program I had come from and when I stopped using padlock.

I never did.

he left, came back and GAVE me one of his surviving cars..saying I should have at least one. Nice car, nice feel, just too slow!

Fate

[idare2bdul]

The point about the Kemtron brushes was a good one, they are on the small side.

Since Kemtron marketed frames for their motors that could be put together with little or no soldering. Many of them had drop arms that were pretty flimsy so they were seldom serious race cars. They were user friendly for the novice builder. You saw a lot of guys stopping their car, punching it and getting a wheelie off the line and just enjoying doing laps with the car. If your friends were driving something similar it was fun. At our local drag strip you could drop in a nickel and race your friends. A few guys scratch built frames that worked especially on the figure 8 at Tandem.