71 replies to this topic

[dc-65x]

I was talking to my friend Adam about building him an early '70s car with a motor that he could hammer as hard as he liked. He's a racer at heart and I wanted him to have a vintage open car he could run hard (like my Starship) without worrying about blowing up rare Pooch, Steube, etc., arms. Vintage look, modern internals equals FUN!

Now, what chassis should we build? Adam suggested we follow through with what we talked about in this thread:

Horsepower For Vintage Racing?

Then I remembered a remarkable achievement in September 1972 accomplished by Dave Smirka at Parma International Raceway. He finished 5th in the A main at the Nats with a production Limpach 888 economy chassis. The cars that finished ahead of him were the then-new Iso style. Steve Bogut also took an 888 to 8th in the main.









Coo... we are going to clone an 888. It's a relatively easy chassis to build and we'll stuff it with a vintage setup with modern guts. Eddie of Eddie's Slot Car Warehouse, Vallejo, CA chose the parts for my "Eddie 20".

The heart of the beast:





Hey, where did that Mura two-hole can come from?

That's up next...

Onward

[dc-65x]

I decided to see what would happen if I turned to eBay for some Mura two-hole C-can parts. I found this lot on a buy it now for $30:





When I got them they were even worse than I thought. Holy smokes, what a mess! After looking at "the remains" I wish I had bought the nice restored motor for $25 that went unsold. Anyway I tore them apart and here's what I came up with:



Elbow grease ensued and I ended up with some useable parts:



So for $30 I can build three C-can setups. All I had to do was spend a Saturday restoring the buggers. .

Here is the endbell and its mods. The brush hoods are notched for shunt wires. All the endbell hardware has been changed out to stainless steel machine screws. The spring posts are insulated with fiber washers and the Laser Dude's Parma heatsink clones have been added:



The arm got touched up in my new toy:





The Eddie 20:





We went with a ball bearing on the gear end. I tinned the can where it will be soldered into the frame and masked it off before painting:



A couple of .030" brass spacers centered the modern arm in the vintage setup:



The magnets were glued in with Koford magnet epoxy. The brush springs are modern Champion light. The motor has been broken in on the Koford power supply... I guess I'd better clone an 888.

Onward...

[68Caddy]

One word: beautiful.
Blows me away, thank you for sharing.

[dc-65x]

Thanks, Nesta. .

I had a PM about doing the brush springs, insulation, and shunt wires. I'm going to talk about it here so we can all share our experiences. I don't know the RIGHT way to do this. I've just read Lee Gilbert's motor building article in Car Model Magazine. Other than that I'm just fumbling along doing the best that I can.

I used two pair of double overhead Champion light springs and some old Tradeship 36D brushes (because that's what I have):



For the light and medium springs I'm using this Teflon tubing. It measures only .028" while most slot car insulation I've measured is more like .035". That's fine, you just have to file a wider slot and the remaining brush material is weaker. You just have to be more careful. For shunt wire I used TQ lead wire:



I usually twist two strands together per shunt, as shown in the bottom of the picture:



I open up the original slot and file in the cross shunt wire slot with a special file from Brownell's gunsmith supplies. It is made to repair damaged slots in screw heads. It cuts on the edges of the file and not on the sides. They come in different widths. The one I use here is .030" wide:



A before and after:



Again, I'm no expert on anything but at least the motor runs. .

[Jairus]

I've been doing it that way, too!


At least for the brush hardware on late model Muras...

What do you do for small brush Mubuchi motors?

[dc-65x]

Hi Jairus,

So far I'm doing the shunts on Mabuchi and Mura A-cans like this:

What If We'd Listened to Mike Morrissey - Page 6

[nostalgic]

Hi Rick,

Fantastic article. I love reading this stuff.

Where do you get the small screws you are using on your motors?

Your attention to detail is inspirational!

Thanks for sharing.

[Ron Hershman]

Please... please... please... when you rebuild that motor, treat it to some P-S Gold Dust or Koford Big Foot motor brushes.

Those brushes you are using are pretty hard on today's commutators.

Beautiful work once again, Rick.

[Jon Laster]

Rick, that picture of Jan's Iso racewinner got me stirred up. Do I have an Arcolite axle around, still?

Your question about endbell treatment - the spring post with a turned-down socket head screw inside it was a West Coast characteristic. At Camen, at least, we had a round-head, slotted screw on top of the post. Usually the screw had to be ground a bit to clear chassis rails, on the front of the endbell. That, and we always used the existing slot in the brush hood, just opened up for shunt clearance.

You should save the later Mura can; it's got the Trinity hole pattern; not terribly unusual, but if you ever do an Ernie replica, that was what they ran...

I'm assuming Adam will get the deluxe 888, with wire wrapped axle tubes front and rear!

Happy building, I should be doing the same!

Jon

[TSR]

Those brushes you are using are pretty hard on today's commutators.

Are today's commutators softer than the old Kirkwoods? I still use genuine 36D brushes on all my old motors and so far have not found a problem with relatively modern arms.

[Ron Hershman]

Yup... the Kirkwood comms had 4% silver in them and were a different "grade" of copper compared to what they use today... no silver in today's comms... making them a tad softer.

Kirkwood comms were also stamped while todays comm "shells" are turned/machined on screw machines. Good copper "grades" don't machine well.

[tonyp]

Interesting....

[Ron Hershman]

What's interesting??? Comms or the "888"?

[tonyp]

Comms... Why would they want to make a softer comm that wears quicker?

[JerseyJohn]

Seats quicker. Less wear on the comm?

[Bob Emott]

Do I have an Arcolite axle around, still?

Jon...

Be careful about using an Arcolite axle... They tend to work like a reamer and eat up the inside of front axle tubing or rear axle bearings...

[Steve Deiters]

The Limpach "888 Wonder" chassis had to be one of the most amazing chassis from the early '70s era. It was extremely simple in its design, but literally worked "out of the box" when tuned to whatever track is was running on for anyone. Typically it was achieved with lead weights on the wings at various locations and altering the spring tension on the drop arm and other tuning nuances.

Combined with Limpach "Fresh Cuts" tires a competitve chassis/car was within the reach of virtually everyone with the most current aero body even if it was for a relatively short while. When I worked at REH Distributing at the time we could keep neither in stock they sold so quickly. In my opinion and in retrospect, Jan did a lot to kick the quality of products of this type up to the next level with all racers and manufacturers benefiting from it.

There seems to be a lot of discussion about "East Coast" chassis from the '70s era. I have photos in my files from the races I covered at Parma and other races such as the Springfield Coke race. I'll have to get them out and scanned so the participants of this blog can see them. It may be just the thing people with interest in East Coast and Midwest chassis are looking for.

They were fun times and I'm glad they happened.

Steve Deiters

[Jon Laster]

Be careful about using an Arcolite axle... They tend to work like a reamer and eat up the inside of front axle tubing or rear axle bearings...

Hi,

Bob! Yeah, they would pick up brass from the axle tube, that was their bearing surface! Not in the rear, although to my utter astonishment P.A. Watson TQ'd (I think) at the Georgia Nats on the Purple Mile 220 with a 3/32" graphite axle in back.

Rick, it's not to late to hit those Dougherty replica heat sinks with a Whitney punch...

And a last word. Jan's approach to a major race was so impressive to me, the pressure he would put on himself to perform to the max would have paralyzed me... and he would come through! No doing it the easy way!

Anyone have theories on the effects of floppies vs fixed pans?

Jon

[dc-65x]

I have photos in my files from the races I covered at Parma and other races such as the Springfield Coke race.

Hi Steve,

I would really appreciate it if you could share any pictures from the 1971 Coca Cola race. Especially Joel Montague's winning car and body.

Rick, it's not too late to hit those Dougherty replica heat sinks with a Whitney punch...

Hi Jon,

I guess I'm not really trying to copy the specific car that was in the 1972 Nats but rather point out how great this simple chassis worked. By building one myself I'll find out how easy a project it is and maybe others will want to scratchbuild one, too.

I'm trying to use parts that are as easy to find as possible. The heatsinks are an exception that I had made for me and just can't resist. I hope I've already shown that Mura two-hole cans and hardware are not that hard to come by and they can be stuffed with modern components.

I hope I can do the same with the rest of the car. A modern vintage racer that... well... looks vintage

[Ron Hershman]

I have photos in my files from the races I covered at Parma and other races such as the Springfield Coke race.

What I want to see is some pics of the chassis that got "straightened out" on the railroad tracks behind the raceway when the 5 o'clock special came flying by.

[Ron Hershman]

Comms... Why would they want to make a softer comm that wears quicker?

Not that they are out to make a softer comm... most hard copper grades become "gummy" when machined. Some copper grades (softer) machine better as they "chip" as they are turned or made on a screw machine.

The Kirkwood comms were stamped from flat silver-bearing copper, then "roll" formed with no machining, but expensive tooling was involved. The material has harder, but didn't matter as it was not machined.

Some of today's comms are produced in much smaller quantities with not much tooling cost on screw machines.

[dc-65x]

Thanks for everyone's input. I'm really enjoying it .

So I'll contribute some 888 chassis pictures. I've had three and shared two of them with others and kept one. Here is the, I believe, early version:





This is like the one pictured in Car Model Magazine, August, 1972. Note the motor bracket, the short outside main rails that stop at the drop arm pivot, and the lack of a gear-side axle brace.

This version has the longer outside rails and a gear-side rear axle brace but no motor bracket. I'm not sure if it ever had a motor bracket:





This is the one I kept and I'm basing Adam's car on it with some exceptions. I'm adding a gear-side axle brace and motor bracket with brace. This chassis is set up for 3/4" fronts and 7/8" rears. In late 1972 pros were also running 5/8" fronts and 13/16" rears so we will be, too. In the same issue of MAR as the race report PdL has a great article on a "No Glue" car that uses this size tires (the "No Glue" car is on my to do list ):





So we need some pans, (or some brass sheet and a nibbler) a motor bracket, and a drop arm. For the motor bracket (if you want to use one) we can go REH or maybe Champion:



The shiny sucker on the bottom right is one I had made. We can also go REH for pans but Parma-style drop arms only seem to show up on old '70s chassis. Here are the REH pans and some "take-offs" from a junk chassis:



I decided to go the junk chassis route and started with this old partial Parma sliding plumber (I just bought a really nice Parma chassis for $15.50 on eBay). Actually this style chassis works great and might be just as fast (or faster) than what I'm going to build but what fun would that be? Really they are fun and I have one with a Mura 20 I run all the time but they are a later chassis and we're building an 888 style chassis.





Here are the remains after I got done with the "solder blob sucker-upper wick". I'm using the drop arm, pans rear axle tube, and my own motor bracket:



Next up well shine these babies up and get after the chassis center section .

[68Caddy]

I'm waiting for the next part of this show and I'm loving it.

This are the things that us new guys love.

Thanks!

[Cheater]

... Here are the remains after I got done with the "solder blob sucker-upper wick".

Rick, surely that can't be the same solder wick bobbin I sent ya a couple of years ago?

Stuff works good, don't it?

[Bill from NH]

Hey, can we discuss the race history in the Slot Car History section and give Rick back his thread, please? Thanks!