80 replies to this topic

[dc-65x]

My memories of Kemtron X503 Wasp motors from back in the '60s is one of raw power on the banked track in the back room of Pasadena Speedway. It is also one of fragility... speed at a price I guess.

I'm not yet in the mood to paint up the bodies of the other builds I've started . So, I'm building up a Kemtron. Here she is in stock form, a NOS (new old stock) motor from the Oakland Speedway collection. Thanks, Rodney :



When I tear into one of these 40+ year old motors something usually goes wrong. This time I have spare parts! They came as a seller's afterthought in an eBay auction. I think they are pretty cool:



This motor looks like a beast. So, I wanted to put into a model of a real beast. I've been saving this beauty, I think it's time to build it up:



I've searched the internet for pictures of this "1957 4.9L Maserati". Here's what I've found for pictures:













Can any of you guys help with a photo that more closely matches this Shark body?

[HarV Wallbanger III]

Great idea, Rick! I have a couple of Kemtrons both new and used. I just may have to get one running, too! Now for a cool old bod to put over it like yours!

Thanks! Keep us posted. I'm sure Dokk can add to this...

[dc-65x]

Hey Barney,

Let's get some Kemtrons on the track!

[Gary Bluestone]

Here is a Kemtron X503-powered Dragmaster chassis by K&B. The bearing supports look to be cast instead of pressed, not sure why? You can see a bit of the side of the motor.

The blue dragster in back is Russkit.

[don.siegel]

Great idea, Rick! Some of my Kemtron/KTM motors have a lot more kick than the Pittman equivalents, but not all... I even have a 4v version of the KTM that I'm saving for a special occasion...

Interesting that you should put up pix of that bod and the real cars: I have the same body and have also had trouble finding the real equivalent! I wonder if they just didn't make it a bit/lot overscale? I had been planning a Pittman DC70X-Kemtron frame combo, but might have to rethink that now.

Anyway, if anybody finds the real car corresponding to the Shark body, all info is welcome!

Don

[Hworth08]

The Maserati is begging for a set of those expensive Russkit wire wheels!

[Howie Ursaner]

My slot car career started the day I put my Kemtron X501 motor into a Kemtron sidewinder kit chassis that I assembled in our oven. I took it to Polks Hobbies in NY and entered the Thursday night race and began a winning streak that night that lasted years. That car made Lou Del Rosario quit racing at Polks and start his own raceway in Elmsford.

[TSR]

I've searched the internet for pictures of this "1957 4.9L Maserati".

Rick,

Looking at the Shark body modeled by Ron Klein, it looks to me more like a Lister-Maserati that was running in SCCA events in the mid 1950s. I will try finding pictures of it. I seem to remember that it was a British Lister chassis originally designed for a Jaguar XK120 engine, mated to a 2-liter four-banger A6GCS engine lifted from a crashed road car.

Kemtron electric motors were of course imported from Japan.

A sentence from my new book:

By 1963, they marketed a line of Japanese motors under the KTM name, using stacked pole pieces, the different versions available, 501 to 503, Mustang , Bronco, and Wasp, were largely defined by the thickness of the pole stacks as well as armature windings. Several of these motors were also used in Kemtron model trains.

Thing is, I was never able to pinpoint the actual Japanese motor maker.

[Prof. Fate]

Hi,

Actually, I think that body is the 300 not the one listed. I have one of those "from the day" with a Pittman 704/5/6 in it.

My Kemtron story is that I did not own one in the day!

In my local stuff, we had a lot with 704 type motors on very short tracks. When we got a bigger track, we also saw our first 36Ds. Mechanically, it was clear to me that the can was superior, so I immediately did a rewind and "owned" the racing on the bigger tracks! Segue to '65 when my dad retired and we spent the summer driving around the country doing the sort of tourist stuff we could not do when we had orders to reach the new station in 24 hours!

So, I hit dozens of tracks all across the country before my dad retired to his home town of Salt Lake.

I was surprised to find them, here, "behind" everyone else I had seen around the country as their racing was still dominated by the "padlock" motors. That was August '65. There was an area-wide race series going on where they were tracking all the results on all the tracks with the intent of awarding "number/plate" to the top ten racers in the intermountain west. Despite my late start, my 36Ds gave me a huge advantage and I ended up with the number 4 plate.

By the end of the year, there were no padlock motors in the field.

Anyway, in '94, I was at MRS in Sandy Utah running Flexis with my friend Kelly when this guy walks in and says, "Hay, I know you... you are the guy who ruined my life!" His story was that he had done well with the padlock motors and could never get a 36D to win for him. He asked me when I stopped using them. And I indicated I had never actually had one! Told him the can story.

He left, came back a half hour later, and handed me a Kemtron/Dynamic car. "You should at least have ONE".

On the BP King, the car runs solid 10 second laps!

Fate

[dc-65x]

He left, came back a half hour later, and handed me a Kemtron/Dynamic car. "You should at least have ONE".

On the BP King, the car runs solid 10 second laps.

Cool story, Rocky. 10's on the BP King, now I have a baseline to shoot for. Although Eddie's King isn't as fast as BP. The track difference might not matter in 10 second lap car though....

Anywho, thanks for all the input, guys . And Howie, what a cool story! Mighty Kemtron’s indeed.

Dokk and Don, on the KTMs, Rodney told me that back in the '60s the KTMs were said to be faster than the Kemtrons. I always assumed they were the same motor sold under different names. I kept my eye out for a KTM and a couple of months ago found a new 3 volt for sale on ePay. I buzzed the KTM and Kemtron 6 volt motors up on my power supply and the KTM sounded MUCH faster .

I also found a “Hop-Up” article on the KTM in an old 1965 newsletter published for a short time in the Bay Area. The author spoke of the differences between the KTM and the Kemtron. One I remember off the top of my head is the heavier wire on the KTM’s armature and the different commutator with tabs to solder the wires to. The Kemtron has the wires solder directly to the comm’s surface !

After a quick visual inspection the rest of the motors look the same. When I build up the KTM I’ll post the newsletter article and closely inspect and measure the components of the two motors.

But firsts, time to “Hop-Up” my Mighty Kemtron :

[HarV Wallbanger III]

I always assumed they were the same motor sold under different names.

Hey, Rick, I thought the same thing, too.

I have two KTMs... one used and one new.

[TSR]

A bit more:

KEMTRON (USA)

The Kemtron Corporation, founded and owned by Levon J. Kemalyan in 1949 in Fresno, California, manufactured model railway cars, locomotives, parts, and accessories. Kemalyan was born February 24, 1907, grew up in Fresno and attended Fresno public schools. He was active in the First Presbyterian Church, having served as an Elder to the Session and on the Board of Trustees. Kemtron employed legendary design engineers in the model-train field. As the new slot car hobby grew and commercial raceways began to appear like mushrooms, Kemtron became one of the pioneers of the 1/24 scale commercial racing in the United States, and by 1962, aided by engineer John Schow Anderson, were producing an array of stamped sheet brass and soldered brass tubing in kit form that made much of the available components for the quickly increasing market. By 1963, they marketed a line of Japanese motors under the KTM name. Using stacked pole pieces, the different versions available, 501 to 503, Mustang , Bronco, and Wasp, were largely defined by the thickness of the pole stacks as well as armature windings. Several of these motors were also used in Kemtron model trains.

KTM stands for Kemtron Train Models. The various KTM/Kemtron motors have differences, but all come from the same manufacturer in Japan, suspected to have some commonality with Igarashi, since the mysterious "Pi" aluminum chassis that also came at one time with this motor has ties with both Igarashi and Strombecker. But I cannot be absolutely sure and the people at Igarashi were unable to provide me with suitable information.

[dc-65x]

Thanks, Dokk. I'm looking forward to building up that 3v KTM. It screams pretty good for an old padlock motor.

Here are the modified parts of the Mighty Kemtron:

1. The stack of laminations (padlock) is drilled out to lose the brass metric screws and replace them with stainless steel 2-56 machine screws.

2. If you look closely at the padlock you can see where two laminations on each side were cut off. This was supposed to increase RPM. I think it just looks cool.

3. The bronze bearings were replaced with ball bearings.

4. The armature was epoxied and static balanced.



The finished motor:







Next up is a rear axle carrier I’ve seen used many times but never tried...

[TSR]

Rick, a real beauty!

[Jairus]

Those pictures of the complete motor remind me of the colorized and airbrushed photos I would see in old engineering brochures. Like they were "better than life", you know?

I agree with Philippe, a real beauty!

[Horsepower]

Rick, are you sure that is a 3 volt motor? I've never heard of a 3 volt KTM or Kemtron, although I do have a 4 volt version and read some years back that 4 volts is the lowest it can be wound due to the multiple poles (5 instead of Mabuchi 3 poles). There was a technical explanation but it was a while ago and I can't remember it. Something about the 5 poles resistance limits. Whatever the case, it's another masterpiece of a motor job!
One other thing-there is a slight size difference that is almost unnoticeable. The KTM fits in the Dynamic cast chassis perfect whereas the Kemtron will take a little modification and wiggle.

[HarV Wallbanger III]

Beautiful job, Rick! Hey does anybody have a rewind number for this motor... I have two of them...

Hey, I have an extra Dynamic motor pod for it...

[dc-65x]

Thanks, guys, the motor did "clean up" pretty nice.

Don, yup the KTM is a 4 volt, I checked the box label to confirm.

Beautiful job, Rick! Hey does anybody have a rewind mnumber for this motor... I have two of them...

Hey, I have an extra Dynamic motor pod for it...

Barney, I found a 1/'66 Car Model Magazine article on rewinding five pole motors. It has a chart of "Minimum Recommended Rewinds For Five-Pole Motors". For the Kemtron the hottest wind is 68 turns (approx 10.4 ft.) of #30 wire for approx. 1.25 ohms ... That sounds like a Girlyman wind to me . I just checked a NOS 6 volt Kemtron arm and it measured .8 ohms. I'd be happy to send you one, Barney .

For a chassis I decided to make a more, I don't know, classic or production oriented design. I'm using a "store bought" rear axle carrier I've seen on lots of vintage cars on eBay:



I replaced the plastic bushings will ball bearings and the steel nuts with stainless steel. It was kind of painful to set up and get everything as square or lined up as possible. I'm happy with the way it turned out and period "Korrect" it surely is :





I want to show some "gear sypher'n". The rear axle carrier can be kept in the same place and the gear ratio changed... onward!

[Tex]

Jeez Louise, Rick!

[boxerdog]

Great build, really brought back memories... they are/were more than competitive with the Pittmans, as I remember it, and the chassis kits were beautiful.

We drove to Fresno in the '60s and visited Kemtron and a track called Telco if I recall correctly. Quite a place.

I still have some Kemtrons and the Kemtron/Ram versions running in road cars and dragsters.

[HarV Wallbanger III]

Hey, Rick, that's a nice old axle carrier... I had forgot about that type. Most all the guys at our track just did some pretty strange scratch brass chassis. Do you think the arm would be faster than the KTM marked motor I have?

Ya, that wind sounds wimpy to me, too. What was the fuse on these? I mean what failed first when rewound? I never ran anything but hand-me-down Pitts, then the can motors took hold and 36D ruled for a short time. Our local track then closed. So I was out of it except for travels with the parents and stuff I could get at the tracks for a couple hrs..

[Gary Bluestone]

This is a copy of some very tatty packaging from Kemtron, showing chassis.

[boxerdog]

... and here is that same chassis:

[boxerdog]

And the car. Sorry if I hijacked, Rick.

I think the Kemtron chassis stuff was maybe even more remarkable than the motors, given the technology of the time. The "fuse" in the motors is probably the brushes and springs?? I don't think anyone had much luck with the round ones, but I could be wrong.

[dc-65x]

No hijacking, Dave .

Everyone, please show us your Kemtrons/KTMs here in the "The Mighty Kemtron" thread .