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Brushless motor mount holes

Posted: Wed Dec 13, 2017 11:59 am
by Peter_B
I've just come to install a brushless motor, in my RC10 Team Car, only to find that the mounting holes on the motor are slightly too far apart for the holes on the RC10 motor plate.

The motor is a Reedy Sonic 540 M3 #269. I bought it nearly new from eBay.

An old brushed motor fits without issue.

Do I need a different motor plate - from the World's re-re for example?

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 12:36 pm
by NomadRacer
There's no different motor plate that I know of. I use the Reedy M3 series (17.5T) in a couple of black re-release motor plates and had to work on the top slot with a small file. I don't touch the bottom hole. I'm guessing the gold motor plate will be the same.

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 12:52 pm
by jwscab
yeah, i think i had to hit the top slot with a file just a little. maybe half a mm at most. probably a standard to metric conversion or something that makes it slightly off.

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:18 pm
by Peter_B
NomadRacer wrote: Wed Dec 13, 2017 12:36 pm There's no different motor plate that I know of. I use the Reedy M3 series (17.5T) in a couple of black re-release motor plates and had to work on the top slot with a small file. I don't touch the bottom hole. I'm guessing the gold motor plate will be the same.
Any idea what sort of file I need? I don't currently have any at all.
jwscab wrote: Wed Dec 13, 2017 12:52 pm yeah, i think i had to hit the top slot with a file just a little. maybe half a mm at most. probably a standard to metric conversion or something that makes it slightly off.
Yeah it doesn't seem to be far out. But it's enough to stop the screws going in.

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:30 pm
by Coelacanth
Peter_B wrote: Wed Dec 13, 2017 1:18 pm
NomadRacer wrote: Wed Dec 13, 2017 12:36 pm There's no different motor plate that I know of. I use the Reedy M3 series (17.5T) in a couple of black re-release motor plates and had to work on the top slot with a small file. I don't touch the bottom hole. I'm guessing the gold motor plate will be the same.
Any idea what sort of file I need? I don't currently have any at all.
You need a round rat tail file. It's basically a thin, round file that you use to either widen or extend a hole. They come in many thicknesses with (usually) a tapered tip. The're pretty cheap and you can buy them in sets with different diameters, or with some flat, round, triangular, etc. shapes.

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Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:33 pm
by jwscab

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:36 pm
by Peter_B

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:37 pm
by Timmahhh
Double check to make sure that the motor doesn't have different spacing for different pairs of holes. Sometimes they vary in spacing around the face plate of the motor.

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:42 pm
by Peter_B
Timmahhh wrote: Wed Dec 13, 2017 1:37 pm Double check to make sure that the motor doesn't have different spacing for different pairs of holes. Sometimes they vary in spacing around the face plate of the motor.
Checked that. All have the same problem.

Re: Brushless motor mount holes

Posted: Wed Dec 13, 2017 1:43 pm
by GoMachV
I had someone with the same issue on a Lethal Weapon motor plate. Apparently some motors are out of spec these days.

Re: Brushless motor mount holes

Posted: Thu Dec 14, 2017 7:37 am
by Peter_B
I picked up a set of needle files and solved the motor fitment issue.

Thanks for the pointers

Re: Brushless motor mount holes

Posted: Thu Dec 14, 2017 7:51 am
by Lonestar
GoMachV wrote: Wed Dec 13, 2017 1:43 pm I had someone with the same issue on a Lethal Weapon motor plate. Apparently some motors are out of spec these days.
This is weird :shock:

Never encountered the issue so far, but good to know!

Re: Brushless motor mount holes

Posted: Thu Dec 14, 2017 8:51 am
by RC10th
I think the issue is with the old motor plates as brushed motors had a pair of holes side by side which were each slightly off center. The RC10/T motor plate had a fixed lower mounting hole so the motor has to rotate instead of slide to adjust mesh. Modern brushless motors have single holes dead center so the adjusting arc is different.

Re: Brushless motor mount holes

Posted: Thu Dec 14, 2017 9:38 am
by Lonestar
RC10th wrote: Thu Dec 14, 2017 8:51 am I think the issue is with the old motor plates as brushed motors had a pair of holes side by side which were each slightly off center. The RC10/T motor plate had a fixed lower mounting hole so the motor has to rotate instead of slide to adjust mesh. Modern brushless motors have single holes dead center so the adjusting arc is different.
I believe we were supposed to use opposite holes when running brushed mills back then already ;)