43 replies to this topic

[havlicek]

I've had what is (I think) one of the dizzyingly diverse and vast array of Mura "B" motor cans here for a long time and keep forgetting to ask what it is.  

The can is less "tall" (from flat to flat), but is "wider" (from radius to radius) than the other B motors and parts I have, so none of my endbells will fit. The metal it's made from is also fairly thin on all sides, so it's not simply a B that has been remachined.

Here it is pictured along side of a "Pink Can" Mura that was rusted beyond repair, so I had to put in a bunch of "wax on/wax off" time with 220 sandpaper stuck to my glass work surface...
but that's another story.  

Anyway, info would be appreciated... especially what the heck kind of endbell would work to be able to someday make a motor out of this thing:
 

 

PS...note how tight the seams are and, despite the rust, how beautifully formed the can is.
 
-john

[raisin27]

Looks to me like a Champion can that I remember from about 1970?

[havlicek]

Maybe Michael???  Any idea what end bell would fit the thing?  It really is a lovely can under all that rust.

 

-john

[Champion 507]

Maybe an Associated can, John?

[dc-65x]

Hi John,
 
It looks a lot like a modified French-Tradeship can.
 
Does it look like the can could have been "sectioned" to reduce it's height? Can you see a seam on the inside of the bearing area?
 
Also, I can see where the rear of the can has been "Dremeled" to it narrow up.
 
Here's what the boys were doing to reduce the height of the 16D motor. This one is a Mura 2-hole:
 

I posted this a long time ago in a galaxie far far away :shock: ....no wait....on another forum a while back. I thought I'd show it here in the hopes of gaining more information on it.

This is a cut down Mura A-can (16D) made by a mystery builder probably in late 1968. It's .590" tall so it's as low as you can go and use the Mura-Versatec magnets. The can uses a 26D end bell ball bearing. A lot of time must have been spent cutting down the end bell to fit inside the can. He even used aluminum tubes attached by screws for the brush spring posts. Lead wire posts were cut off of Mabuchi brush hoods and screwed on over the Mura brush hoods in a reversed position.

I scanned an article from the Nov 15, 1968 Model Racing Journal in case someone wants to give a try. I know it's on my "to do" list.

Thanks in advance for any input,

Rick

[havlicek]

Thanks for the replies, guys!  Still a mystery and no endbell I have will fit!
 
Rick, yes, the bushing strap does seem to have been modified, but the extra bits of metal and even the "overcuts" are extremely uniform from side to side... so looking closely it's unclear (while it's still rusty) whether those are modifications or whether the can was produced that way. While I too think they must be mods, whoever did them was righteous.
 
The can does not appear to have been sectioned as the seam welds seem perfect and undisturbed with no silver (or other) soldering evident anywhere on the inside or the outside... as well as not additional machining to make the repairs smooth. Definitely no seam on the bushing strap either, as that would be a dead-giveaway.  

It really is a lovely can and it would be great to have it be part of a completed motor, but I'm schtoomped.
 
-john

[raisin27]

If that is the can I am thinking of we had to make a 16D or B production enbell fit it by filing it to size.

Doug could be right in that it is an Assosiated can now that I think of it.

[Tom Eatherly]

John, 

I'm sure I'm going out on a limb here, but how about a "Green" can (Bob Green?), used in late '60s in SoCal? They were THE can to have. He started making 'em, and everyone wanted those things.

[SlotStox#53]

Don't know but it actually looks like a motor can my dad won back in the day. It was of similar size maybe larger and was plated... came with Arcos and can-in-can shim.

Never did get it working as never had an endbell that fitted. Remember reading somewhere that Dyna Rewind made a plated can that was an odd size? Could this be an unplated one?

Rick, did you ever get round to making your own cut-down motor?

[dc-65x]

Here's an Associated can:
 

Cool stuff Bob, I'm like'n it too

Sounds like a great time Oscar. I hope I can make it down for the fun. I'd love to watch the greats battle

Here's the end bell kit with some extra goodies like the machine screws, comm cooler and buss bars:



For some reason Associated spaced their brush hoods way father apart than the contemporary Mura B-motor . I decided to use some thick copper B-motor super proofer brush plates and modify them. I elongated the original holes to fit the Associated end bell and better support the brushes:



The brush hoods were notched out to move them in closer as well and soldered to the brush plates. Here a before and after:



I used a period MRJ B-motor "hop up" article to further modify the motor. The end bell got notched for half rail clearance and holes for comm inspection:





The can was soldered together and cut for axle clearance and narrowed at the bearing support. I also soldered that little brass plate included with the Associated kit onto the end bell to help hold the thing together. I'm not sure if that's what it's for but it seemed like a good idea at the time .



The Blue Dot magnets needed some .010" shims to center them in the can and .004" shims to tighten up the air gap:



They slide nicely into the can and I installed the magnet springs and………..the can split apart at the solder joint . I guess that's why Associated later offered the spot welded can . I took the thing apart and applied a big honk'n mound of solder to the joints. I gooped up the top, bottom and back side of the magnets with JB Weld metal filled epoxy and installed them. When the epoxy cured I filed off the excess solder and now the epoxied in magnets are reinforcing the can.

Here is the finished motor all painted up in a textured green finish in honor of the great Steube motors:



Neato old school buss bars, shunt wires and comm cooler:



Yummy, blue dots and ball bearings:



Next up a Billy Steube inspired chassis.

Onward

[dc-65x]

Note the seam and spot welds in the bearing strap area of the black factory-assembled can. Also, this is the C-can version.

They also made an A-can (16D) but I don't know about B-can version.

[havlicek]

Hi Rick,
 
Upon further inspection, the can's oval cut-outs look very much like the Associated ones you show above and are slightly different from the oval Champion holes on their "one-hole" cans.  The only way for me to get a good look-see inside is to start carefully removing all the rust in there so maybe I can see the modifications. I don't mind screwing around (obviously ) with cans that are plentiful, but this one had me worried to mess with it.. .since I thought it might be a one-off that some famous dude produced for racing.  

I still think it must be a modified can as you do and, now that you show the Associated one, think that's as likely a candidate as any. I have found an earlier C-can endbell that almost fits and just needs a tad of trimming top and bottom (the "flats") to go in. It seems as though the side-to-side will be very close and I have a few, so I'm not worried about screwing up one of those.
 
Bottom line is, I can't use the can in its present condition, so I'd be cleaning it up anyway... so I'm going in. I'll post back with more pics and maybe even a conclusion when she's all gussied-up! B-motor magnets and the other Associated "longs" are slightly too short, but can be shimmed top and bottom to fit, so that's something, too.  

If this is a modded can, the guy had skills!
 
-john

[dc-65x]

John,

 

Here's the French-Tradeship 16D can:

 

 

Have fun!

[Tom Eatherly]

You guys always find the neatest things! That is pretty nice. So, it probably ain't a Green can.

Good find, Rick.

[havlicek]

Whoah. I just did a preliminary clean-up on this thing and it is definitely a modified something-or-other. The workmanship is outstanding, with the seams all but disappearing. You can just see the different color (bronze I assume) brazing metal now with the rust removed, as well as the slight differences in width of the two pieces having been put back together at the bushing strap:


 
This all becomes a little clearer on the inside:


 
Check out the top and bottom fit along the side seams... stunning!:


 
This would most likely be a a couple hundred bucks worth of can by today's standards with the time and skill that obviously went into it! It seems really strong as well since it was brazed and not soldered, although soldering in the can bushing and epoxying in the magnets so both can bridge and reinforce the seams is most likely a good idea.
 
I shaved one of those C-can end bells and it fits with the slightest side to side play, and I have very thin shim stock that can handle that... BUT... this can predates C-cans, so that wouldn't be the proper endbell. A B motor endbell would be trimmed along it's two radius sides, but is too short... although that can easily be shimmed as well. I think (?) this would most likely have used a modified Mura 16D end bell ("A") and those were made of MUCH better material than the Mabuchis. I suppose a Champion 16D endbell could also be made to fit and, since this was a can done as a one-off, any quality end bell that was available is potentially correct.


 
The bushing hole is bigger than 6mm and the only one I have that fits is one for the Mura 16D which is close with only the slightest slop.  

Anyway, this is one beautiful can... almost a shame to make a motor out of it now that I can see and appreciate what the builder did.
 
-john

[Gator Bob]

Very cool!   

[dc-65x]

I thought it might be two halves put together. The seam on the side was so perfect.

 

So let's see if it's an Associated C-can which measures:

 

.970 long

.620 high

.885 wide

 

Maybe a cut down French-Tradeship 16D can. The stock can measures:

 

1.035 long

.670 high

.955 wide

[havlicek]

Hi Rick,
 
I'm just heading out but will check the dimensions when I get back, although with mods, the can could have been longer, taller, and even slightly wider (depending on how much height was removed). You'd definitely appreciate what this guy did if you saw this thing in person... very "Thigpen-ish" attention to detail!
 
-john

[Don Weaver]

How about just clearcoating the can so you can still see the seams? I've seen a few 1:1 cars/trucks done this way to protect the un-restored appearance... looks cool!
 
Don Weaver

[Rick]

Didn't Champion at one time sell can halves?...

[Champion 507]

To me, a dead giveaway on the Associated cans is that the holes for the endbell screws are not centered as the Muras or Tradeships.
 
I have two NOS Associated ones as Rick showed about midway down in post #10 (the black one) and the holes for the endbell are in a different location if you compare the "top half" to the "bottom half" of the can.

Also I don't know if it's the camera angle but Rick's motor build appears to have the offset holes for the endbell mounting screws.

[Marty N]

Post #10... are you kiddin' me. That is a work of art. Wow!

[Champion 507]

Marty, Rick Thigpen don't build no junk! Everything he touches turns into PERFECTION!!!

[havlicek]

How about just clearcoating the can so you can still see the seams? I've seen a few 1:1 cars/trucks done this way to protect the un-restored appearance... looks cool!

 
Hi Don,
 
Yes, there is a thing now where entire cars (!) are powdercoated with clear... obviously when the entire body is perfect! Of course, that means that there's no such thing as "ding repair" for that vehicle... a minor dent means replacing an entire portion of the car's body!  

In the case of a slot car motor, the only clearcoats easily available I know of are acrylics, and those will soften at the temperature of a cup of coffee. I could spend some time taking the whole can down in steps to #600 or so with wet/dry paper and then polish it. It's a lot of work, but I have steel chassis I've built and they have stayed rust free after several years in my basement. The smaller scratches and wax residue from the metal polish seem to somewhat protect the metal.  

The only real solution to a non-painted "rust-proof" finish I can think of would be to have the can nickle plated... so I don't know.  n any case, it really is a piece of work and all these years looking at the thing in it's previously rusted state I had no idea what it might be. Wish I knew who made the thing... or who it might have been made for or really any more information about it.
 
Rick, the can measurements on the outside are:

- 1.017" long
- .614" tall (flat-to-flat)
- .930" wide (curved surface to curved surface)
 
So, while the height is closer to the Associated dimensions you listed, the length and width are closer to the French/Tradeship dimensions, but of course any of those could have easily been changed when modifying the can. The radius sections of the can are very close to a perfect/true radius and, as more and more is "sectioned" from the sides of the "arcs" to remove height, you would wind up with something of a "point" at the side seams if you follow the geometry. To a degree, you could always re-machine the sides on the outside to reform a more perfect arc, but you couldn't go all the way to the flats on the inside with round tooling to do that without either marking the flats or leaving a small area not machined. So, there are still some significant "mysteries" that may never be solved with any certainty.
 
So, I can use the slightly modified "C" motor endbell with a bit of shimming on the curved faces, even though it's most likely not what would be totally appropriate (unless this can was done later as a "what if" project by some very talented builder). The bushing kind of bothers me because it's so honking big. The bushing hole was apparently sized for a .250" x 2MM bushing which is the size of the oddball Champion endbell ones, but those aren't flanged. I have some of the gigantic ones later used (retrofitted?) on the Champion which could always be used as raw stock and turned down to .250" OD on the body and a more appropriate OD at the flange. I'll have to think about all this for a while, but I'm not going to just go "gonzo" on this thing as I usually would and simply dive in.
 
-john

[Bill from NH]

If you you want a polished finish, you could try Mothers Mag & Aluminum Polish. It's my 'go-to' polish for shining brass.  I've seen a Slick 7 eurosport chassis with a mirror finish that had been achieved using it.