53 replies to this topic

[dc-65x]

In November 1969 the late great Pete von Ahrens set a world record on the Blue King track with my favorite can motor of the 60's, the Mura B-motor. Yes I know, overall it was not that successful of a motor but I also love King Cobra and Honker Can Am's and of course........the Bill Thomas Cheetah. 

 

Below is a link to a great thread by PdL on the car and the restoration of it:

 

AMCR "Blue King" record setter

 

Here is how the chassis looked in the January 1970 Model Racing Journal race report. Click on the photo to enlarge it:

 

 

It was rediscovered and 50 years and taken their toll: (photo courtesy of LASCM):

 

 

Steve Okeefe worked absolute magic restoring it to its former glory (photo courtesy of LASCM):

 

 

PdL also worked magic restoring the complete car back to as raced (photo courtesy of LASCM):

 

 

Here is the race report in MRJ, "Von Ahrens Breaks All Records At CM":

 

 

 

 

Time to start building a B-motor car with a square wire chassis.  

 

 

 

[Bill from NH]

If I remember correctly, an issue of Car Model has a PvA chassis build article. Not this chassis, but either another flat wire chassis or at least partially flat wire.

[dc-65x]

Here's the article Bill from Steve Okeefe's sub-forum. It's earlier likely mid 1969 when actually built, but still a very cool PvA design.

 

PvA Shows You How To Build The Latest 1/24 Open Class Chassis

[dc-65x]

I put the wrong page of MRJ up in my first picture of the thread. It correctly shows the PvA car now.....sorry!

[dc-65x]

Here's what I've found for my chassis. PvA offered his own line of parts. Here is his ad from Model Racing Journal in October 1969:

 

 

I have this cool drop arm:

 

 

Also have these half rails:

 

 

I'm thinking I'll try these Parma pans:

 

 

Cobra low profile motor bracket:

 

 

And finally what really makes building this chassis possible is Cobra .050" SQUARE wire. The label says flat wire but it is actually .050" X .050" square same size as PvA's chassis:

 

[Isaac S.]

Cool drop arm, and I love flat wire. It just looks cool.

[dc-65x]

My good buddy Rodney acquired a complete square wire PvA chassis years ago and built it up into this beauty:

 

 

 

The body is one of my early attempts at fogging paint job. Rodney did the hand lettering:

 

 

[Isaac S.]

Wonderful car Rick. Great craftsmanship. And thanks for the great pictures. 

[dc-65x]

Thanks Isaac.

 

For my motor I was gifted this "20/40 Circular Milled Can" by Rodney:

 

 

I got it cleaned and trued up:

 

 

The gnarly screw holes and motor mounting surface..........

 

 

.......was milled nice and flat and the holes tapped for 2-56 machine screws:

 

 

Magnets are next.....

[dc-65x]

Here are the super duper B magnets and they are huge:

 

 

But not quite huge enough.     They still need shims on the top and bottom to fit the can snugly:

 

 

The axle cutout in the can also needed to be opened up to clear the 1/8" axle with 7/8" tires. I also cut some clearance on one side of the can for a motor bracket brace:

 

 

Now, with a .750" diameter spur gear, it's the corner of the magnet that hits the axle and dictates the minimum motor angle to about 12 degrees. That's the same motor angle as PvA's.

 

 

With this can and a junk endbell in the setup jig I can start bending wire for the chassis........

[dc-65x]

With my Champion jail door car finished up I can carry on with this build. I was going to start the chassis but I'm waiting on a new tool to arrive in a few days. I can't help it, I a tool freak.  

 

I broke out a NOS repackaged Mura end bell from Quaid Experience.........very psychedelic!  

 

 

The bottom of the end bell was milled to clear the frames half rail. The top has a small slot milled to clear the buss bar:

 

 

Holes were also bored top and bottom for comm cooling/inspection:

 

 

Buss bars are made up from .039" piano wire:

 

 

I'm adding thick aluminum Certus Super Proofer plates under the brush hoods:

 

 

Here are the goodies for the spring posts:

 

 

The Mura self tapping cap screw on the right is replaced with a 2-56 fillister head machine screw. The screw head is ground down a bit to fit inside the Mura brass brush spring cup instead of on top of it. The shorter setup give more clearance for the frames half rail.

 

I'm also using a fiber washer under the spring to isolate it from current:

 

 

A very low profile pan head machine screw is used on the bottom left. This will help with clearance for the forward axle tube brace:

 

 

A view of the top and the buss bars:

 

 

The end bell should be good to go:

 

[dc-65x]

I'm really happy with how the end bell turned out so with that done I dug up an armature for the project. 

 

PdL used a "bubble gum" arm for his PvA restoration so I'm doing the same. Mine is from a many years old eBay lot of B-motor parts:

 

 

The arm isn't dirty, the dark spots are armature dye that was slopped all over the thing.     I scrubbed off all I could with lacquer thinner.

 

It's a REHco repackaged Mura 27-28 wind:

 

 

I cut the comm and polished the rest of the arm:

 

[Isaac S.]

Cool arm. Will make for a fast motor. 

[Vay Jonynas]

 

Here is how the chassis looked in the January 1970 Model Racing Journal race report. Click on the photo to enlarge it:

 

MRJ V1N21 p8 jan 9 1970.jpg

 

It was rediscovered and 50 years and taken their toll: (photo courtesy of LASCM):

 

post-22-0-05988200-1540602628.jpg

 

Steve Okeefe worked absolute magic restoring it to its former glory (photo courtesy of LASCM):

 

PvA King Record Car (7).jpg

 

PdL also worked magic restoring the complete car back to as raced (photo courtesy of LASCM):

 

PvA King Record Car (9).jpg

 

 

 

Very interesting chassis concept! Do you think it would/could still be a winner on today's tracks/surfaces?

 

[dc-65x]

Modern cars are way faster Vay. But hammering an early open car on a Blue King is an amazing experience.

 

Here is Steve Okeefe's scale drawing of PvA's record setting chassis:

 

 

I started chassis construction with the rear axle tube:

 

 

I saved the PvA half rails and used them as a template to make my own.

 

 

Mine are on the outside of the PvA half rails:

 

 

Rather than bend up a part and solder it on one at a time I made up all the parts for the center section. All the bends are either 12 degrees or a right angle:

 

 

The center section is all in one lump:

 

 

The motor bracket and brace are next.......

[Pablo]

Wheeeeee   

[dc-65x]

I filed a notch in the frame rails........

 

 

.........to allow the bottom motor screw to be used:

 

 

The motor bracket acts like large gusset to strengthen the frame where the notch was cut:

 

 

A rear axle tube brace like PvA's attaches to the motor bracket:

 

 

The center section is ready for that PvA fabricated drop arm next:

 

[dc-65x]

I'm very lucky to be able to add a little touch of PvA's craftsmanship to my build with his assembled drop arm:

 

 

Of course it can't be proved but his ads say he personally made the things he sold:

 

 

The the double plumber rails:

 

 

Here they are cleaned up:

 

 

The drop arm and other components with the plumber hinge tubes trimmed and the overall length reduced:

 

 

 

 

 

[dc-65x]

Soldering the pans on worked so cleanly I thought I'd share what I did. The pans are securely soldered on without the wide soldering iron track usually seen on the pan next to the hinge wire.

 

Just use the tip of the iron to secure the extra long hinge wire on the side where the body mount pin tube will go:

 

 

Now solder the extra long pin tube to the end of the hinge wire to hold it in place:

 

 

A "blob" of solder on the iron tip is placed on top of the pin tube and hinge wire. As the solder flows down to the pan, run the iron's tip along and off the pan dragging any excess solder with it:

 

 

After washing the pan on the top off you can see how little cleanup is necessary for it to look like the one on the bottom

 

 

Both pans and plumbers are ready to install on the chassis:

 

 

[Isaac S.]

Looks great!

[dc-65x]

The plumber halves are tied together. I used Kapton tape again to make sure the didn't get accidently soldered to the frame:

 

 

The pan assembly got a good wash with Dawn, high pressure air blow dry, a good polishing and finally a WD-40 soak:

 

[dc-65x]

Moving right along, the pan down stop gizmos are added.......

 

 

.......and the plumber upward stops on the center section:

 

 

With the square wire I could use my disk sander's miter gauge set to 12 degrees on the chassis parts. Look at the tight fit you can get by just sanding a bit at a time and sneaking up on the parts fitting together:

 

 

The chassis is finished:

 

 

 

 

 

Time to paint the motor can and finish up the motor.

[Dominator]

Beautiful work.

[Isaac S.]

Looks fabulous

[dc-65x]

Thanks Dominic and Isaac. It was fun working with the square wire.

 

I finished up the B-motor with a coat of black wrinkle paint. I got some nice fine grain "wrinkles" by using 2 light coats and baking at 200 degrees for an hour:

 

 

And I couldn't resist adding one of our repop comm coolers. The first ad I have for the Thorp comm cooler was in May 1970:

 

 

That's a few months after the early 1970 timeline for this build. But let's just say I had a friend that got a prototype of Thorps gizmo and passed it on to me. 

 

 

The shunt wires are tucked in out of the way:

 

 

That green "bubble gum" arm really stands out:

 

 

Here's the masked off and tinned area to solder in the motor: