56 replies to this topic

[dc-65x]

Time to build up a new Ram-Boochie this time for a small sports racer. The RAM armature really perks up a 36D Mabuchi:

 

 

 

 

An eBay seller currently has the oilite bearing version of these kits for sale for $19.99. The bummer is, for some reason, he's charging $19.10 for USPS Priority mail shipping. There is an option for USPS ground for $13.85.

 

Here's a link:

 

ORIGINAL VINTAGE RAM REPLACEMENT ARMATURE FOR 36D SLOT MOTORS W/OILITES

 

This is a pretty good period how-to article on building one of these motors from Rod & Custom magazine October 1966. I'm going to keep this build in the 1966 time period as best I can:

 

 

 

I'm going to "hop-up" my RAM "hop-up kit" even more with a couple of vintage goodies.

 

First is a Kemtron aluminum endbell. This one sure won't be melting anytime soon  

 

 

Then the RAM brushes, coil spring and plungers will be replaced with a modified Simco torsion spring and Pittman 196A brushes:

 

 

Up next, the first step is modifying the Mabuchi can........

[Isaac S.]

Ill be watching!

[don.siegel]

Great to see you back in the saddle Rick. And you might even inspire me to do one of the couple Ram-Boochis in my drawers... 

 

What's the advantage of the Pittman brushes over the Ram ones? 

 

Don 

[Bill Seitz]

I used a ball bearing Ram-Boochi for several years in the 60's. Actually, I think I might've had two. It could hold it's own against most motors down the straightaway, although that 36D mass was a challenge in corners. I remember making brush springs out of large safety pins, a mod one of the slot car magazines touted for motors with this style of brush gear. I never had a problem with melting the endbell, but the Kemtron aluminum endbell would've been a nice addition had I known about it.

 

Mine eventually suffered broken brush holders. I was unable to find suitable replacements which permanently sidelined the motors, and I long ago discarded the remains.

 

Incidentally, the ad says a 5-pole armature, but it's really a 7-pole armature.

[dc-65x]

Thanks Isaac.  

 

Hi Don. I've been "ruminating" on this build for quite some time. Fitting a 36D sidewinder into a relatively small Lancer Hamill body with a full interior has caused quite a bit of time consuming component juggling. The choice of Pittman brushes is a personal preference. But I think I should do a comparison between them and the harder RAM brushes. I can compare amp draw, subjective RPMs and check for arcing.

 

That large safety pin sounds so "vintage hop-up" Bill. I don't remember it but I love it! That's pretty much what the Simco brush spring is. That type of spring provides good tension and is so much easier to install than the coil spring and plunger.

 

I've got the can cut about 3/32" shorter and the gimbal bearing removed.....

 

 

.....and the aluminum endbell attached with four 0-80 machine screws:

 

 

Next I'm making a new can bearing housing.

[don.siegel]

Impressive - but not quite 60s technology Rick! At least nothing I could do when I was 14... hmm, can't really do that now either...  

 

Very curious to see how you're going to mount that new housing - ball bearing of course? 

 

And yes, I was wondering how you were going to fit the whole shebang into a Hamill! 

 

Don 

[Dave Crevie]

The last drag car I built before leaving slot cars in 1966 used a 36-D I built using the Kemtron aluminum endbell. It had ball bearings and a rewound arm I did. 

 

Not sure why anyone would choose the Pittman brushes over the Ram silver ones. They were the only ones I could find that didn't vaporize on 36 volts. Rick, I hope you do a performance evaluation on the two. I'd like to know if my choice was sound.

[dc-65x]

In 1966 I was 16 years old Don. But when I'm building a car from that time I don't think about a kid building it. I think about the older period enthusiast with access to more technology.......and money for those ball bearings!  

 

Boy Dave, I have no experience with 36 volts and what works and what doesn't. My preference for the softer Pittman brushes is thinking they would be kinder to the commutator. The one time I used the hard RAM brushes they seemed pretty rough on the comm. But I'll try them again on this motor.

[dc-65x]

Time to fill that gaping hole in the motor can. I lathe turned a ball bearing holder from brass bar stock:

 

 

 

There is a pocket for the back of the armature to fit into:

 

 

That allowed me to shorten the can a bit more. Here's a comparison with a stock 36D can:

 

 

The motor mounting holes have brass nuts soldered inside the can. The screw spacing is the same as the endbell:

 

 

 

 

[Dave Crevie]

You do great machine work, Rick. I like when a machinist breaks sharp corners with a 45 degree chamfer. Shows real pride. 

 

As to silver brushes, I went with what the big guys were doing. I do know that motors tended to spin up faster because there was less friction with the silver brushes. Plus, theoretically, lower resistance. Since we always "freshened" our motors before each race, com wear was seldom a concern. And as I said, silver brushes were the only choice in drag racing for big motors on 36 volts. I exploded a lot of motors doing that. And when I say exploded, I mean literally "exploded". I think your choice might be correct on an irreplaceable vintage arm, though. 

[dc-65x]

Thanks Dave    
 

..........And yes, I was wondering how you were going to fit the whole shebang into a Hamill!

 

 
As I work on fitting everything inside the Hamill body I'm finding that it's taking lots of "little things" to get everything to fit.
 
The most obvious is shortening the motor can. But the endbell got some modifications too:
 

 
The bearing flange on the endbell was trimmed 1/32". The allows the gears to push up that much closer to the motor for a 1/32" wider tire or a 1/16" narrower track to fit under the body.
 
This doesn't help the motor fit but the brush spring plate was modified to slide farther forward. Otherwise there a chance the brush arms could contact the metal endbell and short out.
 
Notches were also filed into the endbell to allow the brush spring to hug the top of the motor. That allowed the spring to clear the molded in motor detail and the body to sit down lower on the chassis:
 

 
The motor is now far enough along to act as "jig motor" to build the chassis:
 

 

 
Time to start on the chassis.

[dc-65x]

For motor brackets I used these Kal Kar pieces. Turns out the mounting screw spacing is the same as the 36D Kemtron endbell. I needed 2 packages for their flat brackets, The factory bent offset bracket was not used. I bent my own offset to get the spur gear as close to the motor as possible. Another little thing that gets everything to fit under the body: 

 

 

They had to be heavily modified starting with enlarging the axle bearing hole for 9/32" tube and moving it up 1/16". That lowers the motor for scale 1 1/8" rear tires:

 

 

The start of modifing the "flat" Kemtron bracket to fit my Ram-Boochie can:

 

 

The top of the brackets need to be removed to allow the motor to be lifted out of the chassis:

 

 

The pieces of the rear end ready for assembly: The little U-shaped rods will reinforce the modified axle tube holes in the bracket:

 

 

Getting all these pieces soldered together was........interesting. Getting everything aligned and soldering the bracket to the axle tube without the little U-brace falling off and visa versa was.......

 

I used the technique Mike Steube showed in his chassis building video (every scratch builder should watch it). That is, heating half of the bracket / axle tube / U-brace solder joint at a time. Mike taught to tack things together then reheat the joint watching the solder turn shiny as it heats and stop before the entire joint melts. Half of the joint holds things together and the other half gets the solder flowing. Repeat the process on the other half of the joint.

 

 

[Pablo]

     

[dc-65x]

I want to keep my chassis design style within the timeframe that  the motor I'm using was first introduced and used. For example I wouldn't do a "jail door" multi-rod chassis for an early 1960's open frame Pittman motor.

 

But the Ram-Boochie was on the track in mid 1966. That's when the multi-rod chassis was being developed in the Rod & Custom Road Race Series. So a jail door style it is.

 

My first rail is big (3/32") for the big 36D motor. It runs full length to the back of the motor:

 

 

The rest of the rails are 1/16". A short U-shaped rail between the big rails to tie them together.  The third and fourth rails were next. I made them in 2 halves thinking I would scrap to much rod trying to make them in one piece:

 

 

But I gave the one piece a try for the fifth and sixth rails and got it right on my second attempt:

 

 

I guess it really is, "better to be lucky than good"..............

 

Time to get it installed, clean things up and see what I've got.

[JimR]

I just picked up the oilite Ramboochie.

Comes the question: put it on the shelf for my retirement or put it in a motor for my fun.

[dc-65x]

Hi Jim. You could build the Ram-Boochie now and then buy something else for retirement.     You can't have too many goodies for retirement.

 

Here's the chassis cleaned up and ready for the drop arm and body mounts:

 

 

 

[Alchemist]

What a work of "magic" Rick!

 

Simply awesome, as is the norm of your craftsmanship!

 

Thank you for sharing.

 

Ernie

[dc-65x]

Thanks Ernie.  

 

I finished the drop arm. It's a style I like and have use before:

 

 

 

I have plenty of travel for the arm like I most often see in the early cars running on bumpy tracks:

 

 

Closeups of the attachment of the guide tube:

 

 

 

The body mounts are next and will finish off the chassis.

[Pablo]

  

[dc-65x]

I've got her done Pablo:

 

 

 

 

 

 

I mocked up the car with chassis, motor, wheels, tires and body and I think it looks really cool. Everything fits and works together great. I'm really looking forward to getting this one on my track. 

 

Next up are the wheels and tires. I have 4 different rear tires to show.

[dc-65x]

Okie dokie then, I'll press on with this build thread.  

 

Front Russkit tires and repop wheels:

 

 

They were ground down to 1" in diameter:

 

 

I'm using repop Russkit wide rear wheels and grinding the tires to 1 1/8" diameter.

 

Here are Cox Chaparral Firestones by Ortmann. I also have some old stock of the same Cox tire by Canadian Paul's Slot Car Shop (currently he refuses to ship to the USA):

 

 

These are Cox Cheetah Goodyears by the French Slot Cars Tyres:

 

 

Last is a vintage silicone Firestone tire by MDC I've had very good luck with:

 

 

 

 

 

 

 

[Isaac S.]

Lots of choices! 

[dc-65x]

And I can't wait to try them all Isaac.  

 

But to do that this car need a motor. When I buzzed up the motor it vibrated like an electric toothbrush. 

 

The comm was anything but round so I cleaned it up:

 

 

On the static balancer the armature really "swung down" on 2 poles and it took significant pressure to get it to roll on the razor blades. After all the drilling it now rolls easily on the blades and never stops at the same place twice.

 

The arm was also got a coat of epoxy that was heated to allow it to thin and soak down into the windings. Any excess epoxy on top of the windings got wiped off. I also did a thread wrap around the wires where they attached to the comm:

 

I'm interested to "feel" how the motor buzzes up now........

 

 

The can got a coat of red wrinkle paint:

 

 

Motor assembly is next.

[Pablo]

        In an emergency you could probably power your house with that thing. Looks like a Detroit Diesel arm 

[dc-65x]

Here's the  Ram-Boochie all in one lump Pablo:

 

 

After the static balancing it's not silky smooth but it vibrates much less:

 

 

The is no brush arcing and it draws .6 amps a 6 volts: