3573 replies to this topic

[68Caddy]

Barn
I'm so wind up that my arms are going everywhere?
**** I could never do what you do, more power to ya got one for me?

Nesta

[Bill from NH]

A couple of my old Mura manufactured arms from the 1969-70 timeframe came with flat bottom balance holes drilled off-center in the stack. I believe the flat bottom balance holes were made with an endmill rather than a twist drill bit.


Nesta, you're regressing!

[Jairus]

I thought only Mura and Certus used the "flat" sheet metal drill balancing?

Nice Wildcat John! What are you using the weird brushes for? Did I miss something? I have a set with shunt wire brushes that don't fit ANYTHING as they are thicker in one direction... idea?

[havlicek]

Hi Jairus,

Thanks! The brushes (along with some other stuff ) all came with the motor. I probably won't use them, as I have a bunch of nice brushes here that fit the Tradeship endbell nicely. Check your PMs

-john

[HarV Wallbanger III]

Your right Bill it is a endmill. I have several Mura's but all have a twist bit style holes. I had never seen these used on Mura's before. The older French motor has drill bit holes and I thought it was a 68 unit??? Also I had never seen Mura's off center like this.

A couple of my old Mura manufactured arms from the 1969-70 timeframe came with flat bottom balance holes drilled off-center in the stack. I believe the flat bottom balance holes were made with an endmill rather than a twist drill bit.


Nesta, you're regressing!

[havlicek]

I wound the arm for the Wildcat today and it is suweeeet! I did a #26 and it's about perfect for the setup (I exchanged the magnets for some modern D can mags). The motor sings and I'm sure none of my childhood Wildcats sounded like this one Whatever car this thing winds up in will definitely move! It's not "on the edge", but draws about 2 1/2 amps and doesn't get too warm at all. In the right period chassis/body (maybe even a thingie?), it would be lovely. I just have to clean it up and add a couple of doo-dads but...The "Wildcat" lives!


-john

[Jairus]

With that ball bearing poking out through the can houseing... it looks so serious! Way to go John.

[havlicek]

Thanks Jairus. Yeah, I like the way the bearing looks and I used little black button head screws for the can and they look sharp against the yellow too...but this thing really sounds aces. I just have to solder the hoods, add shunts and spring insulators and maybe spring post protectors. I have a guy here (where I live) that wants the motor...but I might just build me a Thingie I also have to say THANKS! to Don for sending me this thing. It's been a trip down memory lane and a helluva lot of fun too!

-john

[Tex]

Looks great, John! Keep it up; when I get around to trying my hand at motor building, I'll need a mentor.

[havlicek]

Hey thanks Tex. I don't know about any "mentor" stuff, but I'm more than happy to share what info I have.

-john

[Phil Irvin]

JOHN,

I have to ask who does your balancing? I like the way it is done and looks. You do so many arms and you do such FINE work. Maybe you have your own balancer so you can do it your way!

PHIL I

[Prof. Fate]

Hi

Sadly, thinking that we might run some actual jaildoor, but not knowing what people had, I came with cars, and a bag of motors and parts. I had hoped to build motors on the spot to suit the play.

And, of course, the convention was canceled, I drive back tomarrow with all these old rewinds, magnets, hemi and russkit cans and brushes and springs and all the bits to assemble the frankenmotors as needed.

even a wildcat!

Bomker did run the pittcan lotus 30 in Oxnard, and a couple others. But no the fun serious silly stuff.

Fate

[HarV Wallbanger III]

Wild Cat looks real neat!

[havlicek]

JOHN,

I have to ask who does your balancing? I like the way it is done and looks. You do so many arms and you do such FINE work. Maybe you have your own balancer so you can do it your way!

Hi Phil,

I do everything on my arms...prep, wind, tie, epoxy, balance and true the coms...as well as dewind and cleanup old arms that will be rewound. I do the balancing as Tony P would say "old school" on a pair of razor blades mounted in a substantial block of aluminum that Rick (RGEO) made up for me, but had done it previously using a block of wood with grooves for the blades and thumb screws to adjust it. Some people use a blob of clay that they stick the blades in but I have never had much success that way and even as a kid didn't like that. As the arm gets closer and closer to being balanced by drilling the heavy poles and removing material, you need to keep slightly readjusting the blades and to do this with any confidence and accuracy, you need some method of controlling the movement of the blades by very small amounts. A "balancing block" is the best way to do that I've found. Rick T. has a similar setup he uses for those gorgeous motors he builds (when he needs to balance an arm) that uses machined pins instead of razor blades, but the idea is the same. Pablo has dome rewinding and balancing this way as well with good results, it just takes a bit of practice.

It's not as accurate as a good operator doing dynamic balancing...BUT...it is plenty accurate enough once you get the hang of it. "Static balancing" such as I do relies on having a smooth arm shaft for the arm to roll on across the blades (or pins). I recently rewound some Russkit 22's for someone here and those have splined shaft ends. In order to overcome that, I slid some tubes over the shaft ends and because the tubes didn't fit precisely I could only guess at what I was doing. I got them better than what they were but not as good as they could be.

Once you get the hang of balancing, then you need to decide the way you'll remove material from the arm. Over the years, people have done it one of several ways: drilling, grinding, grooving (running a cutter lengthwise down the pole)...as well as adding weight to the lighter poles with epoxy (this also had been a cheat people used in race classes that didn't allow balanced arms since it doesn't leave as obvious results).

Hi Rocky,

It sounds like it would have been a load of fun...next time!

Hi Barney,

Thanks man, these old motors offer a whole lot of fun and potential performance. It's a whole different paradigm from the current bullets, so you just have to see them as valid in their own right. In their own way, they're even more gratifying to work on because the potential for improvement is much greater than with a current motor where "it's all been done". On this Wildcat, I felt it was worth the investment to add the bearing and the expensive Tradeship endbell...it was!

-john

[havlicek]

Here's the Wildcat all cleaned-up and sporting it's new Radio-Shack-Antenna spring post protectors It sounds awfully nice...so nice that I started another one. I got the can all stripped and cleaned-up, installed the can bearing and cleaned up an arm to wind for it. I filled-in the magnet tabs on this one instead of cutting them off...why?...I don't know I got a bunch of old and sometimes really rusty stuff from someone in trade for a motor job, and there are some useable arms in there. So I picked one and cleaned it up. It started out like the nasty-looking one on the left and now is (with a Kirkwood com I had) ready to be prepped to wind. Since the first one was a single #26, I think this one will be a #28.



-john

[Jairus]

I think it would be cool if you had a "Power by Havlicek" sticker to put on the side of your motors!
I know that I would be proud to put said sticker on one of my cars....

[havlicek]

...hey, that's a pretty cool idea Jairus. They make little ink-jet stickers that would be good for that. Maybe over the weekend I'll see if I can come up with something. Thanks for the idea!

-john

[Phil Irvin]

GO FOR IT.......

phil

[havlicek]

For Wildcat #2, something a little milder (and probably a little closer to what might have been done back then)...a #28 awg. At around 1 1/2 amps no load, it's a puppy dog. I dyed the stack because it was still a little rusty and beat-up.



-john

[Horsepower]

How'd you get the splined shaft out of the bearings?

[havlicek]

Hi Gary,

How'd you get the splined shaft out of the bearings?

Well, this arm blank wasn't original, and neither the can bearing nor the endbell (replacement Tradeship) are original either...but I don't think that would be too difficult. Actually, the two Russkit 22's I wound for someone here both had splined shafts and those weren't a problem.

Speaking of problems, I took apart Wildcat #2 after a little break-in and found a big chunk of the end of the com plastic had come off. I don't know if it's because the com is old and brittle...or even if it was cracked beforehand and I hadn't noticed, but this is a mild wind so I'm surprised and bummed out . Oh well...time to wind another one

-john

[havlicek]

I wound another arm for Wildcat #2. This time a #28 sgl. with a tad advance on the com and I cobbled it together from bits I had lying around as I'm pretty much out of the vintage stuff. The blank is of unknown origin, the com was salvaged from an "el-destructo" arm that someone gave me (not easy to get it off in one piece with the epoxy and all). It really is a sweet arm that draws an amp or less and should be able to run all day with no heat problems. Still, it winds out really nicely and seems like a pretty good representation of a vintage rewind. Interestingly, this arm draws less current than the first one with the cracked com did, but winds stronger.



-john

[Dooner]

Another beaut!

[havlicek]

Thanks Tom! There was a significant amount of work in this one just on the com. Someone had cut the tabs (I'm guessing for endbell clearance) so after removing it from the old arm and cleaning it up I had to carefully groove what was left of the tabs so there'd be somewhere for the wires to lay into. I then tied it up really good to be sure that (even though it's a fairly mild wind) those wires don't go anywhere. I winds exactly the way I was hoping...sounding strong but drawing very little current and staying very cool. Right now, there's a fairly hefty arigap in the can as this arm is a few thousandths smaller in diameter than what I was going to use and I tested it with light vintage springs. I imagine that with some shims on the magnets, stronger springs and soldering the brish hoods for better current flow to the brushes, there's still a bunch more performance that could be wrung out of this thing, but I like it just the way it is.

-john

[havlicek]

Here's the arm all dressed-up and ready to go to the party I shimmed the magnets and closed up the airgap, centered the arm in the field pretty much, soldered the brush hoods to the brush carriers and experimented a little with different springs. With the light springs made for the endbell that I have, the arm spinds up really nicely and only draws maybe 3/4 of an amp (no load). With heavier modern springs, it spinds up faster but current draw almost doubles...although it's still only an amp and a half Probably either way is fine depending on gearing and whatever chassis it winds up in, but as this Wildcat was intended to be more of a reasonable performer I left the light springs in place. Besides, I thought they looked cool

So I have this one done as a fairly mild #28 awg (but still a considerable upgrade from stock) and can drive, and the first one done more as a barn burner #26 awg endbell drive. Here's..."Son of Wildcat":


-john