3573 replies to this topic

[Victor Poulin]

Vic, I got brush springs bigger than that motor!

Bill,
You wouldnt believe the rpm these little things put out . Its just the arms that seem to be the weak point.
And Bill remember,, Its not how big it is, but how you use it !!


Vic

[Phil Irvin]

I got a Puppy Dog with the Chinese unbalanced arm in it and it didn't run worth a poop. I had an OLD X 12 P.S. with 38 degree advance that had worn the can end shaft out. After measuring it. I cut the can end spacer so the wires bearly cleared & the can bushing was riding on a new shaft. I then had to shorten the comm a bunch to make it fit. It JUST bearly clears the bottom of the brush hoods. I had to move the mags down to center the arm in the magnetic field. Does it run Yea baby. It is one HOT runner.. After 20 laps. It turned the arm dye a dark red. Is it faster than the american arm Puppy dog? YES SIR. I would not try it a whole race tho..I just take it out & run it with the American arm puppy dogs... Kinda makes them mad when they see another puppy dog out run them sooo bad. Maybe thats why the puppy dog 12 arms don't go that wild on timing

PHIL I.

[Victor Poulin]

I got a Puppy Dog with the Chinese unbalanced arm in it and it didn't run worth a poop. I had an OLD X 12 P.S. with 38 degree advance that had worn the can end shaft out. After measuring it. I cut the can end spacer so the wires bearly cleared & the can bushing was riding on a new shaft. I then had to shorten the comm a bunch to make it fit. It JUST bearly clears the bottom of the brush hoods. I had to move the mags down to center the arm in the magnetic field. Does it run Yea baby. It is one HOT runner.. After 20 laps. It turned the arm dye a dark red. Is it faster than the american arm Puppy dog? YES SIR. I would not try it a whole race tho..I just take it out & run it with the American arm puppy dogs... Kinda makes them mad when they see another puppy dog out run them sooo bad. Maybe thats why the puppy dog 12 arms don't go that wild on timing

PHIL I.

Phil,
I tried to do the same thing. I had a Koford x-12 arm that I thought I would stuff in it. What I didnt give any thought to, was the fact that the com end is much longer. The stacks fit great, and I really thought I was on a roll until I went to install the endbell Oops !!! not gonna work My fault, I should have known the 12 arm was much longer. With the strong magnets that come in these motors, I would think an x-12 arm would be a rocket in this thing.
Did you gauss the mags in yours? I did, and I got a 988 and 979. Not bad for the size huh? That was after giving them a zap. I plan to have alot of fun with this thing !!

Vic

[Bill from NH]

I'm guessing a cobalt 12 arm might be a better fit since it's wound on an arm blank that uses shorter spacers. But the arm stack length is still the same. I don't have one to try it.

[Alchemist]

Ernie, I think your right !! I just think its neet to have a new motor to toy with.

Vic,

I concur that it's KOOL to have a new "Havlicek" motor to play with - how EXCITING! Actually any of my "Havlicek built" motors are fun and I have them sitting in compartments to look at and enjoy until I can built plastic/composite chassis' for them?!!!!!

I sure wish I was close enough to see and hear your motor run Vic!!!

Ernie

[Victor Poulin]

I'm guessing a cobalt 12 arm might be a better fit since it's wound on an arm blank that uses shorter spacers. But the arm stack length is still the same. I don't have one to try it.

Bill,
I was thinking the same thing. It would br interesting to see what it could do

Vic

[Victor Poulin]

Vic,

I concur that it's KOOL to have a new "Havlicek" motor to play with - how EXCITING! Actually any of my "Havlicek built" motors are fun and I have them sitting in compartments to look at and enjoy until I can built plastic/composite chassis' for them?!!!!!

I sure wish I was close enough to see and hear your motor run Vic!!!

Ernie

Ernie,
I cant wait to get it back from John !!

[Alchemist]

Vic,

Please "tell all" when you've received the motor back from John and have done some "testing" on the track. Looking forward to the field report!!!

Ernie

[Phil Irvin]

Phil,
I tried to do the same thing. I had a Koford x-12 arm that I thought I would stuff in it. What I didnt give any thought to, was the fact that the com end is much longer. The stacks fit great, and I really thought I was on a roll until I went to install the endbell Oops !!! not gonna work My fault, I should have known the 12 arm was much longer. With the strong magnets that come in these motors, I would think an x-12 arm would be a rocket in this thing.
Did you gauss the mags in yours? I did, and I got a 988 and 979. Not bad for the size huh? That was after giving them a zap. I plan to have alot of fun with this thing !!

Vic

I wish I had a gauss meter but .....I really did shorten the comm using my comm lathe. The tabs are about .030 from the underside of the hoods. I thought it would throw a comm segment but it hasen't yet . I didn't hit it with the zapper yet...Maybe I should and just see if it runs cooler.

OLPHRT
PHIL I.

[havlicek]

Hi Guys,

My results gaussing the magnets were almost identical and they are pretty stout little things alright, measuring somewhere just under 1000 which is around the same as vintage Mura magnets of various types that are more than twice the size and weight. In a slightly heavier can of a different design, they would probably do even better...but I don't know much about that stuff, Barney is one guy who could probably add to that. The two Hawks that I did for Guillermo and Vic were 40T/#28 winds and on a short stack like the Hawk arm, they measured around .3 ohm. Even though these weren't "critically-important" motors, I didn't have the nerve to go to the mid-30's and a .2 ohm wind...especially with the stock com or the cut down Mura com, as either may prove to be a weak link. Also, the endbell bushings seem to fit slightly sloppy and don't "snap" in and stay put on the two motors I worked on. If those bushings are either wobbling only a miniscule amount...or actually rotating...or both under load, that will cause heat, brush wear and premature failure. I probably should have done something to try and lock the bushings in better, and it's even possible that replacement bushings would fit better. I have on occasion tinned the outside of bushings and bearings to get them to fit an endbell better, so that's one possibility. If I remember correctly, the bushings are 6mm (?) so there's all kinds of possibilities for swapping them if need be.

Just to put my thoughts on the motor together:

1) The can is a soft/thin metal very much like the SCX motor's can. They are fragile and easily distorted so mounting the motor solidly without messing things up might be a bit more trickier than usual. Not a deal-breaker though.

2) The endbell seems fine, although it's worth it for Hawk users to check the bushing for movement.

3) The magnets are light and strong...seemingly the same (or at least a close equivalent) as the SCX magnets. There's plenty of oomph there to support a pretty stout arm and the airgap seems tight in stock form...again just like the SCX motor.

4) The stock arm is definitely the weakest part of the motor. I don't know what they use to glue the winds, but I would bet that it's not epoxy. The little "once-around-and-knotted" tie under the com seems more of a visual thing than an actual help. It's not taught and since whatever the glue is has proven to be weak, that tie isn't going to do much. Interestingly enough, I pried up the top lam on both arms as they look a little thinner than a .014" lam and they both measure around .010"...and oddball size for sure. I found this in the SCX long shaft motor also, although the RX42B seemed to have .014" lams. Could be the way I measured things, but I didn't want to spend the time to completely take-apart the arms to see for sure.

5) The motor in general seems like an appealing package for those who want to be able to build/rebuild motors. I'm guessing that the magnets in the TSR/Falcon/S7 motors are just as strong and those motors are well known as to their performance, so here's a motor that can be tinkered-with. Actually, here's a motor that really needs to be tinkered with (or at least checked-out), as opposed to the other "non-endbell" type motors that need to perform reliably out of the box.

Like the SCX RX 42 and 42B motors and variants, people who want to rewind can see this little guy as a relatively inexpensive platform for all kinds of performance tweaks as well as rewinding. The SCX motor was
significantly cheaper the last time I checked, but staying with the SCX endbell kind of limits what you can do. If you swap out the SCX endbell for a new PS C can endbell, you're significantly past the Hawk in terms of cost. So the "value" of the Hawk is in it's buildability/rebuildability, both for performance and reliability gains and for the enjoyment that might provide for "motor-heads". For those who prefer to just buy and toss motors, the Hawk may not be the best option...but the racers will figure all that out for sure.

-john

[HarV Wallbanger III]

Since I have not seen a Hawk yet all I can say if you have one that is running hot crank on a little more spring pressure and it may help. This will not make the arms last any longer but it should run a little cooler as they have a little hotter wind arm in them.
Whats funny is people say that they are made in the same factory but the P/S Chinese seem to last better as Gorski had a couple that he raced in the Retro East series and they ran good. Like I said the springs may be too weak for the wind..... good luck!

[havlicek]

Hi Barney,

Makes sense to me because the brush springs are liable to be "bouncing"...even more so with a motor where the com might not be so "true". A bit more spring tension could help to keep those things in contact with the com.

-john

[Victor Poulin]

Vic,

Please "tell all" when you've received the motor back from John and have done some "testing" on the track. Looking forward to the field report!!!

Ernie

Will do Ernie

Vic

[havlicek]

I've had this 26D project bouncing around on my table for a while and seeing Pablo's 26D build got me inspired to pick it up again First off (and what got me started on this in the first place), I got this weird motor from Jeff Easterly that's sort of 26D size. The arm is exactly the same OD as a 26D Mabuchi, but the magnets are a little thinner and so the whole can fit's almost perfectly inside a Mabuchi 26D. The thing is, the magnets are really nice and measure 998 and 987 on my meter...nice! I actually did one build where I installed Mura hardware on the endbell and it's a real screamer, here's the motor stock:



So what I did here was cut away all of the can except for a "ring" that's the size of the magnets and their clips. It turns out that a .007" steel shim outside that "ring" makes it a perfect slip-fit inside of the Mabuchi 26D can, and these magnets are the strongest I've found that are adaptable for a Mabuchi 26D. For the can, I chose a lovely NOS Classic 26D I got from Switchblade (thanks Gary!). When I popped the blister open, I found the stock ball bearings had all come out and were stuck to the magnets...no problemo as I had plans for that anyway. Here's the can:



Next, I removed what was left of the Mabuchi ball bearings, leaving just the aluminum housing on the can. Then I sleeved a modern 6mm bearing with 1/4" brass tubing, reaming the tubing out just enough to get the bearing in and "mushrooming" the tubing so the bearing and sleeve would be a snap fit in the Mabuchi aluminum housing. To make sure it didn't go anywhere, I peened over the edge of the aluminum housing inside the can to clip the bearing more solidly in place and then ran a ring of epoxy around the outer edge of the bearing race and onto the steel can material (since aluminum doesn't epoxy well). Here's a shot of the can inside with the strong magnets and bearing installed. Final airgap is somewhere around the same as the stock magnets and I can (if I choose) shim the inside of the inner can shim as well to tighten that up:



Next up, I got a minty-fresh NOS Champion 26D endbell from Roger at Mid America and went to work. I replaced the stock brush tubes with 36D ones and soldered them to a pair of pentroof carriers. This will make sourcing brushes easy and might help the motor to live longer. I added a pair of spring post protectors and then sleeved another modern bearing to snap-fit the endbell bushing recess. You can see the brass sleeve (as well as some goop I gotta clean out of there), as well as the small amount of trimming/relieving I did to the undersides of the where the brush tubes go to clear the new com:



All done, the setup looks pretty stock except for the steel "can-in-a-can shim" showing through the vent holes and the bearing visible from the endbell. The arm is a Tradeship 26D blank that I swapped a new drill blank shaft onto and installed a Mura com that clears the brush hardware. The stronger com will also let me weld the com connections, which will be important since I plan on doing a #27...maybe even a #26 single for this thing. The setup is about as good as I can get it without really reworking the endbell with more heat protection. I like it as-is though because it mostly looks fairly stock, and what I've done to it is at least in "the spirit" of the period if not absolutely "correct". I think this is going to be a really nice 26D:



-john

[Horsepower]

Quote: "When I popped the blister open, I found the stock ball bearings had all come out and were stuck to the magnets...no problemo as I had plans for that anyway."

Uugh! Dontcha just LOVE those "NOS" parts?

That aside, that motor looks great! It looks like I have to go digging again and see if I can find an endbell to fit the left over Classic can I have here. That bearing replacement is a super good idea anyway, because as you can see, those factory bearings weren't from the "A" list.

[Robert V.]

Hi John
Awsome rebuild on that 26D, can in a can ball bearings your like the mad scientist of slot car motors, please post a pic when you get the arm done i will be very curious to see how it runs.

[Robert V.]

Here is my latest rewind and build, i call it Mura back from the dead, as you can see in the first pic the arm had no comm (Thanks John for the comm) and the end bell to the left that it came with was the wrong size so i replaced it with the one on the right i think it's an old Parma 16D, i gave it a new paint job and put on the scratch made sticker, the arm was rewound 50T of 29 gauge and this one has high heat epoxy resin it's dry but not heat cured yet, i also replaced the can and end bell bushings as they were very sloppy. The motor runs very nice pulls about 1 1/2 amps and runs pretty cool.

[havlicek]

Hi Robert,

Thanks for looking. I'm really doing pretty much the same stuff people have been doing to hotrod motors for decades. The difference is that now we have some alternate choices for materials and parts and I'm not so hung up on perfect period correctness that I worry about comitting the occasional venial sin The Mura can shims and magnets for 16D motors are functionally the same as what I've done here, and they make a huge difference in those motors. These magnets are even stronger, so I knew I had to use them. The factory Mabuchi bearings can be fine when they're in good shape, but they're nowhere near "precision" and are also prone to self-destructing...sometimes even before you get to use them! Swapping 36D brush hardware is also an old practice, so I've learned a lot from right here...even though I was "there" back then and apparently asleep at the wheel Because I'm still a little worried about the motor, I've decided to do a double wind as they run cooler and seem more efficient at producing revs and power...makes you wonder why they don't seem to be around anymore. On this one, I'm going for the gusto and doing a #28 double which should be a pretty hairy wind. I've got a recipe here for a .2 ohm #28 double on an FT16D arm that I need to just check to see how it will work out on the 26D stack. I will post the results when I get it done.

I love what you did with that old Mura It's entirely in the spirit of all the home-rewinders of the 60's...even the wind itself at 50T/#29 is "right there". Your metallic silver paint is becoming a "signature" as well and looks mighty spiffy on the old motors The actual winding, epoxying and tieing also looks really nice too and you seem to be gaining confidence a lot faster than I did when I got back into winding. I posted everything I did here (ad nauseum), but never really liked most of what I did until fairly recently...bravo!

Hi Gary,

I need to thank you again for such a clean can. I've got a pretty good pile of Mabuchi and Mura stuff here, but most all of them need LOTS of TLC just to be workable. On this one, even after I flattened and removed the magnet tabs on the can, the paint was still clean and I love the fact that I can keep it stock looking on the outside (well...pretty much stock anyway). The motor isn't for anyone in particular (at least as of now) so I get to do what I want to it and the Champion endbell seemed really necessary for what I had planned to do here. When I'm done, there will be a LOT of time in the motor but it will be a "sleeper"...looking pretty stock at first glance. I like that, so thanks again Gary!

-john

[Alchemist]

Robert,

Your motor came out real nice - I like it!!!

John,

That's another nice piece. You guys take some great photos and I have to compliment you on the clarity of the pix. Thank you gents!

Ernie

[Horsepower]

Anytime, John! The great part about this stuff is seeing the finished product.I only wish I could hear it "wind up" in the back straight!

[Robert V.]

Thanks Ernie
I really enjoyed rebuilding this one, i am glad you like the pictures i am shore most of the credit goes to the very good camera digital Canon EOS Rebel XS.

[Phil Irvin]

ROBERT,
The timing looks to be well over 40 deg. Thats a little too much for the older motors. I would back it off to about 30. It may be a strong runner but run very hot. Nice job tho...Try & find an advance checker if you can. It will come in real handy.

OLPHRT
PHIL I.

[havlicek]

Hi Robert,

I knew there was something I had forgotten and Phil is right. The timing looks way out there. For a basic way to set "high-timing" on a 16D sized arm, set the com tab in line with the trailing edge of the stack ahead of it..."ahead" being in the direction of rotation. It's a good visual way to limit things from getting too far out of range.

-john

PS...the above ONLY applies to "regular" coms where the com tab is centered on the corresponding com segment...which is the vast majority of old and new coms. There are however coms from Tadeship for example where the tabs are set to "build-in" timing advance when you center them between the gaps of two poles on the arms. In those cases, centering the com tab as you would for a neutral advance (or no advance) visually, will actually result in an arm with timing advance. These are relatively rare coms though and I don't know of any besides some of the Tradeships that have this feature.

[Robert V.]

Thanks Phil and John, well i lined the comm tabs up with the center of each stack i thought that was neutral timing, oh well may be i will get one of these done the correct way, i guess i will have to tear this one apart again and it won't be easy as the comm on this one is super glued and has epoxy on it. Next i need to find one of those timing tools. I am starting to understand why most people in this hobby will not do their own motor building it's like some kind of lost art with the last few people trying to figure it out.

[havlicek]

Thanks Phil and John, well i lined the comm tabs up with the center of each stack i thought that was neutral timing,

Hi Robert,

That's an easy mistake to make and sometimes these verbal descriptions can be a little difficult to get clear. Her4e are a couple of illustrations I cranked out to give a better "picture" of what's going on:

1)Neutral timing is when the com tab is centered on the gap between the stacks (or more accurately...the "poles"), not the poles or stacks themselves. Here is an illustration of neutral timing viewed from the top or com end of the arm:

This arm will spin approximately equally well in either direction.

2)"Advanced Tming" is when the com tab is rotated more towards one or the other stack or pole as per below. In the illustration, the com tab is roughly lined-up with the trailing edge of the pole and will spin faster in the direction of the red arrow. Lined-up about like this could be generally/vaguely called "high timing" and is generally enough timing advance to get a good extra bit of "snap" out of an arm without going too far.


This direction of timing advance will result in an arm that will spin faster CCW as viewed from the endbell end of the motor, which is generally what you want. I hope this helps

-john