21 replies to this topic

[Pablo]

I was asked to make this bag o' parts into complete drag motors for my good friend Bud

 

 

I'll begin with the one in the upper left plastic box; it's obvious he wants this arm (S16D, 46 timing, .560 OD) in this setup, looks like a PS can/EB with segmented mags, hole is about .563

 

 

 

[Bud Greene]

Party hardy I'll be watchin' while I rework the chassis

[airhead]

I will bet that one of the motors ends up in his GoCart.

[Pablo]

I bet it won't. Too big too heavy too much torque, too much hot timing.

[Pablo]

This first motor I will call "Alpha", a Pro Slot S16D, 46 timing, .560 OD arm to be mated with a PS can/EB with quad mags, hole is about .563. The owner made that decision to mate that arm with that setup, which I respect. My job is to make it sing. Obviously my main job is to hone the mags.

 

The good news is, the bushings and EB hardware are in perfect alignment

The bad news is, the mags are about ten thou misplaced (fore and aft) in the can, and the can retainer tab gizmos obviously need to be trimmed before honing

 

 

[Pablo]

Bud, motors will be engraved, Alpha, Bravo, Charlie, Delta.

Match the letters up at the tops of the cans, in this case, "A".

This eliminates confusion and makes note-taking easy. Each motor will be different.

 

 

The can tab gizmos on Alpha need to be trimmed so as not to foul up my honing.

We know the 2 sides are skewed 10 thou fore and aft. The question is, is it worth completely removing and re-setting them? Maybe yes, maybe no.

 

Which presents the next question, are they aligned properly with respect to the comm/EB hardware? If they are out of whack in 2 respects, out comes the Acetone, remove mags, trim tabs, re-glue correctly. If not, why fool with them to correct a 5 thou per side discrepancy?

 

To get that answer, I simply found a similar type PS arm of .513 OD with the same exact end to end measurement, put it in the setup, and eyeballed the comm alignment. It's perfect.

 

 

All I have to do is grind those tabs a hair before honing, and we are off to the races

[Pablo]

Koford SBF II brushes pre-radiused and individually marked for polarity - "-" is neg, "+" is pos.

 

 

Lead wire tabs pre-tinned with paste flux. Bushing secured with Loctite CA Professional

 

 

All the above will be done exactly the same on A,B,C, and D

 

Honing Alpha quad mags to .580 went very smoothly. I space the tool (shaft ends) so I don't end up honing things I don't intend to . Used an old Speed FX EB from our AMSRA handout days, took the Porter Cable into the bathroom, set it on reverse, turned some cold water on, and started gently honing, little by little.

 

Cleaned up with Dial liquid soap and some blobs of Neon, $1 at WalMart

 

[Pablo]

Ballpoint pen technique used to ensure the comm slots don't act as knife edges - all it takes is a soft swipe on each slot

 

 

Magnehone ensures bearing surfaces are smooth and true. This is motor building 101, Bunky

 

 

EB is engraved for polarity

 

 

Once assembled, Alpha started up on the power supply immediately. She didn't seem to have an "attitude" like I'd expect a 46 degree timed S16D with a tight airgap to have. At 3v she drew 1.7 amps, sounded nice and happy, and 5 minutes later reached 1.89 amps, cool as a cucumber, steady as a rock.

 

After a short time out and a re-oiling, I fed 'er some volts and it was beautiful. No heat, no vibration, no problems. I'd say Pro Slot is producing some really quality products here. With some standard TLC they come alive really sweet.

 

Alpha is a 100% success

[Zippity]

Ballpoint pen technique used to ensure the comm slots don't act as knife edges - all it takes is a soft swipe on each slot

 

I read somewhere ages ago, that a toothpick is a safer bet. 

[gotboostedvr6]

You want comm slots razor sharp. Knocking off the sharp edge will cause premature brush and segment electrical burn.

[Pablo]

The remaining 3 Pro Slot arms for Bravo, Charlie, and Delta are identical, tagged "16D", engraved "38" degree timing. So I shifted into production line mode - faced all 6 rotating surfaces with the Magnehone and swiped the slots gently with my pen. Ever watch a barber strop a blade with a leather strap? He's not trying to dull the edges of the razor - he's simply removing any microscopic burrs.

 

3 sets of Koford SBF II brushes were marked for polarity and pre-radiused

 

[Pablo]

Bravo - setup is a used, rusty Speed FX can/mags/EB with BB's at both ends. Is it useable? Let's find out.

 

 

 

-are the BB's serviceable?

-is everything aligned?

-are the mags secured, aligned and true?

 

If the above are all good, I can clean it up and make it happen.

If not, it may be a waste of my time, and better to start from scratch with a new EB, can, etc.

They are easy to find and very inexpensive.

 

[Pablo]

Upon investigation, the Bravo setup is bad. Not only is it rusty, the alignments are way off.

Sorry, Bud, I can't put a nice PS .500 arm in it. Couldn't sleep at night.

 

The mag hole is .570 - that would give an airgap of 35 thou per side

 

So I opened up the bag holding the brand new "Charlie" setup, thinking I would be willing to put a .500 arm in a .570 hole if, repeat if, the setup was nice. And I find rust all over the can side BB. Looks like a fire ant hill of rust. So Charlie is dead also. Right out of the bag, the quality is bad.

 

Delta, ain't gonna happen, the hole is probably the same as Charlie - .570, and it's just crazy to think a .500 arm would perform well with that big of a hole. Not to mention, it is probably rusted as well.

 

Sorry, Bud, you got only one really nice motor out of it - Alpha. That one I will guarantee for life.

The other parts, sorry, I just can't work with.

[Bud Greene]

Can't you replace the bearing and shim the magnets

[Pablo]

Hoo boy, the short answer is, "yes" of course I can.

But would it be the smart thing to do? I honestly don't know, but I have serious doubts.

Here are some reasons I can think of right off the bat:

 

To shim the mags and re-do the BB would require completely stripping it.

At that point you are looking at a bare $6 mass produced can.

It would require straightening and possibly re-soldering the seams if it's bad.

The tabs would have to be removed and smoothed to allow shimming.

The BB hole would have to be taken down to bare metal and re-tinned.

Then re-glue the mags, possibly re-hone them to match the hole to the slug, install new BB.

The EB would probably require drilling new mounting holes to get everything re-aligned.

 

That's a lot of custom and time-consuming work to get, in the end, a bastard sized (.500 OD") arm to work.

ProSlot doesn't sell a .500 16D arm - somebody made a custom order for those for some specific application.

I wish I knew what he was thinking.

 

In the end, what would you have? It's up to you. That's why the very first question I asked was ""what airgaps do you want"? .513 in a .560 hole makes good sense - it's a proven combination. Alpha leads me to believe a .560 in a .580 hole also works well. But a .500 arm? IF I did shim them, I'd shoot for about .550.

 

If you want to pay money for that amount of work, OK. I'd need 2 pair of these:

https://e-slotcar.co...-shims-pch-012/

 

If they were my motors, I'd do the following:

-Bravo, shelve it, or use it as a jig motor. It's rusty and it's way out of alignment.

-Charlie, I'd order a new PS 706B .540 OD with 45 deg. timing and leave the .568 hole as is.

-Delta, I'd order a PS 706B .560 OD with 42 deg. timing and hone the hole to .580, same as Alpha.

[Bud Greene]

Don’t worry about it

[boxerdog]

Might not be cost-effective, but some of the strategies for adapting c-can mags using "donor" cans as shims could produce a smaller hole.

[Zippity]

Would the large air gap motor be any good on a flat track?

[Pablo]

I have other options for you, Bud.

 

-shelve Bravo and Charlie setups, and save your three .500 arms for something in the future.

 

-I have a PS Speed FX 16D setup from our AMSRA handout days, which I blueprinted and installed what appears to be a .560 (Viper?) arm and honed the stock mags to about .580. It ain't pretty but it's RIGHT.

It has been sitting for several years. I just tested it, draws 2 amps at 3 volts, dead smooth dead cool, and absolutely screams. No BB's - but nice fresh tight bushings, new brushes, never even been in a car since the new arm was installed. I'll give you a buddy deal on it. And lookie here, it's aready engraved "C-3" LOL This would become the new "Charlie".

 

 

 

-I opened up the Delta setup bag, the alignment is not perfect but close enough that minor adjustment would make it so. No rust buildup on the BB like Charlie had. Hole is about .565. I have a very slightly used PS tagged 16D .513, 42 degree arm which I know will perform well in it, again if you want it I'll give you the buddy price

 

 

(sorry about the Kleenex shwarf on the comm tab )

 

You'd keep your Pablo labor costs way down, get a great price on a motor and an arm, save your other parts for another project on down the road, and come out of this with 3 nice motors

[Pablo]

Bud has given me green light to proceed on the options in post #19

 

The new Charlie-3 is bagged up, ready to go.

 

Now we turn to the Delta double BB setup. Can and EB were both soaked in a puddle of lighter fluid to dissolve any factory protective mystery Chinese animal fat grease

 

[Pablo]

A few minor adjustments for alignment, arm spaced and installed, easy day.

She draws low amps, but runs slightly warm, which is typical for a 16D with a big airgap and ceramic mags.

 

Very smooth, and by no means a "screamer". If you want a soft motor, Bud, Delta is your answer

 

[Pablo]

Bud said track test results from yesterday at the drag strip are:

Alpha A++

Charlie A++

Delta A++

 

He's happy. End of story