78 replies to this topic

[dc-65x]

Thanks Dieter, that's really much appreciated.       I hope my pictures will help show the details of these great old cars that the grainy newsprint pictures hide and encourage others to build their own versions.

[dc-65x]

My chassis is finished and I have to admit that it turned out to be one of my favorites.

 

 

 

To me, for a vintage Pro chassis, it has what Rodney calls, "The Look":

 

 

A close look at some of the details often lost in the old newsprint photos:

 

 

You can run you hands over the chassis and not feel any sharp edges. All of the ends of the piano wire, brass rods and tubes are chamfered smooth. They are not just chopped off with a Dremel cutoff wheel. That's a habit learned from my apprentice machinist days at the "deburr bench" that I can't shake.  

 

 

Next up is my "inspired by" Pete Zimmerman motor build.

[stoo23]

Mmmm that looks "Luverly" 

As you say, it most definitely has "The Look" !!

 

That's a habit learned from my apprentice machinist days at the "deburr bench" that I can't shake.   

  and a great thing too !!

[Larry Horner]

That one truly is a looker Rick ... nice work!   I love it when you can make parts do double duty and one of my favorite details here is using the pan pivot rods to push the body pins up higher not to mention that the pins are themselves the down stops.

[Bill from NH]

Another family jewel Rick! Will this one get a Lola coupe body?

[dc-65x]

Thanks Stewart.   

 

Those period Pro builders were clever folks for sure Larry. 

 

Bill........... ............

[dc-65x]

For my motor I'm going with a setup like the Zimmerman motor that was used by the fastest qualifier of the race, Ray Gardner:

 

 

Below is an article on that motor from the very next issue of the MRJ newsletter:

 

 

 

My chassis is setup for clockwise timed end bell drive. I found a very scary looking early "pre-tied" comm wires Lenz arm. 

 

I wish I would have taken a before restoration picture of the sad looking thing. It looked like a hand grenade waiting to explode.  

 

I checked it with an ohm meter and it read .2 to .3 ohms so I cut the comm and tested it in a cobbled up setup. It sounded great and ran smooth so I finished restoring it as best as I could:

 

 

 

As I remember from PdL's book, it was shortly after this race that Cukras hooked up with Mura and the comms were tied along with other improvements to help the motors last. 

 

Anyway I'll give this arm a try. It doesn't need to run and Endruo.........thank goodness!   

[dc-65x]

With the armature ready to go I gathered up all the other parts into my build box:

 

 

First order of business is to replace the 1968 Mabuchi can's crappy so called ball bearing with the Champion oilite bearing that Zimmerman used:

 

 

Getting that aluminum bearing housing out of the Mabuchi can has always been problematic for me. To remove it, I've tried cutting, pounding and grinding with a variety of Dremel stones. I eventually get them out but it's never been easy........until now.

 

I use an end mill in my milling machine to cut away the crimped end of the bearing housing a few thousandths at a time until it just falls out......easy peasy:

 

 

I also removed the 4 little tabs in the can to make room for the big Versatec magnets:

 

 

The Champion bearing is soldered from the inside..........

 

 

.........and a nice bead of solder flows around the outside of the bearing:

 

[dc-65x]

Next up is getting magnets in the can. I'm going with new old stock (NOS) Mura semi-can shim, Versatec magnets and Certus magnet centering shims:

 

 

The magnets got a good zap........

 

 

...........and the came up pretty high on the gauss meter:

 

 

The magnets are too small for the can and it's the shim's job to center them and hold them in place. Getting this accomplished has been problematic for me short of gluing them in place:

 

 

The problem is getting the little tabs (red arrows) bent around the edges of the magnets to lock them in place while they are in correctly aligned.

 

 

I've finally figured out an easy and effective way to do this. There are probably other ways but the one I'm going to share sure worked out great for me.

 

I used 2 Mura A-cans, an armature slug and loosely assembled the magnets and shims into the semi-can:

 

 

Then slide motor cans over each end of the magnets and shim.........

 

 

..........but leave access to the little tabs open to bend them tightly against the magnets with a flat blade screwdriver:

 

 

Look how nice and tight the tabs are formed around the magnets. All that's left is to do is add the usual U-shaped magnet spring clips:

 

[olescratch]

  How can the U shaped spring-clip get past the bent tabs?  I don't see where there's any use for them.

[dc-65x]

Hi John,

 

The U-shaped wire spring clip goes between and against the bent tabs to further reinforce their pressure against the magnets. I've seen motors with and without them. I figure they can't hurt so I use them.

[dc-65x]

The NOS Mura first gen "unmeltable" endbell is attached to the can with four 0-80 panhead stainless steel machine screws:

 

 

The endbell is tapped for 2-56 stainless steel fasteners for its "brush gear":

 

 

At the back are the brush hoods and hex brush holders soldered together.

 

The early Mura's used Mabuchi style flat top brush hoods (front-left) and soon switched to the "pent-roof" style (front-right):

 

 

Endbell ready to go:

 

 

 

Time to put all the pieces together.

[Bill from NH]

Rick, are these brush holders for 36D or 16D brushes?

[dc-65x]

Hi Bill,

 

They are for 16D brushes:

 

[dc-65x]

The motor is finished. Draws about .9 amps at 3 volts and doesn't overheat.

 

 

 

 

Next I need to get the wheels and tires going:

 

 

 

[stoo23]

That's a VERY Tidy looking Motor !!! 

[dc-65x]

Thanks Stewart

 

Here's an Alpha "humongous" donut glued to a small (by todays standards) vintage rim. How to find out where to trim off the excess tire?

 

 

I'm using my little hobby lathe with an Xacto knife mounted in a boring bar tool holder. Measure the length of the brass spacer (.500") butted up against the wheel. Line up the blade with the end of the spacer and dial the lathe cross slide that .500" plus any extra, in this case .075" and cut:

 

 

The same principle applies to the other side of the wheel:

 

 

Then using my "olden times" tire machine the OD is cut:

 

 

Ready for grinding:

 

 

Here the fronts are finished and the rears need to be finish ground after they "rest" for a bit:

 

[Jay Guard]

Hey Rick:

I love the "spacer trick", Thanks for that, but I have two questions...

 

1. Did you have to use some kind of shims to mount the x-axto blades in the boring bar holder?

 

2. Did you consider somehow using the Sherline lathe to also cut the O.D.?  Would love to hear your thoughts on a set-up for that.

[dc-65x]

Hi Jay, I'm glad you found it useful.

 

I have always thought I'd need some dedicated tool holder for Xacto blades. Then one day I just stuffed a knife in a boring bar holder and it works just fine:

 

 

I use my old tire trimmer for the OD instead of the lathe because I'm lazy and it's all set up ready to go.

 

I'm going to use my lathe next time. I will use a smaller 3/8" boring bar holder rotated 90 degrees from the side trimming setup and fit a smaller No.11 blade knife in it. 

[Jay Guard]

Rick:  Great info, from the angle of the picture I couldn't see the X-Acto knife body. Thanks for the clarification and inspiration.

[dc-65x]

Here is something else Jay that I've found helpful. Maybe it is nothing new but it is to me and has made installing multiple lead wires easier in the Cox guide.

 

I hope I'm not being "Captain Obvious".............here goes.  

 

I've been tightly twisting multiple lead wires together to get them to go through the hole in the guide. But then the tightly twisted wires resist inserting the fragile little copper retaining clip into the guide.

 

By only twisting the very end of the wires together and then soldering them makes it easy to insert the wires through the hole in the guide. The rest of the wires remain untwisted making it much easier to get that little retaining clip installed:

 

 

With that, here's the finished roller:

 

 

 

 

The wheel inserts are Russkit with "mystery" resin cast knock offs added:

 

 

 

I also added pan springs like Mike used:

 

 

My "inspired by" tribute to Mike Steube's first Pro race winning angle winder.........."Look at that funny car, the motor is crooked. That will never work!"   

 

 

I can't put it off any longer.....the body is next.

[Martin]

Nice trick with the soldered wires Rick, do you trim off the soldered part of the wires once inserted or just fold it back? 

I am thinking you would cut it off so the braid lays flat?

 

Painting weather is coming.  

[dc-65x]

Hi Martin,

 

This time I trimmed the wires off flush with the bottom of the guide. I have also cut off the soldered wires and "combed" the remaining wires out flat under the braid. Can't make up my mind.  

[Pablo]

It can't get any more perfect than this.           

[Paul Menkens]

"Look at that funny car, the motor is crooked. That will never work!" I love how whenever my nonslot friends see a car the 1st thing out of their mouths is "that's a stupid way to mount a motor, that'll never work and it'll wear out the gear"!