Need help with motor timing

[MONSTER]

On another note: How short is TOO short for brushes. The arent discolored, but one is a bit (maybe 1/8) shorter than the other. Longest being only slightly shorter than 3/8.

[Eau Rouge]

If it is now at .280" there is no way it was an oversized comm in that can—you would have already hit the laminations. It's probably a machine wound arm in a quad can. I don't know anything about that particular motor, but if it is already that small from one cut, it's probably had a hard life to this point. You should be ok, now, though.


I know you mentioned brush life before. Brushes are CHEAP. I put new ones in a motor every time I cut it, probably 95% of the time. Depending on the motor (some have more brush wear than others), I don't ever let brushes get short enough to notice wear. The shorter the brush gets, the lighter the spring tension you will have on them, and the less power the motor makes, regardless of how much "power" is left in the brush. A Checkpoint or Orion/Peak V2 can go much longer between cuts/brush replacements because of their efficient design. I would cut those motors less often and replace the brushes less often, as well.


Make it a habit to replace brushes in any motor if it needs a massive cut like what you gave that one (-.020"). You literally took off 66% of the total usable lifespan (+/-.030") of the comm in one cut.

A normal cut should only be taking off .002" at the most. If you are rebuilding your motors before there's a big trench in you comm (the way you should be), you shouldn't have to take more than a .001" cut and maybe a clean up cut after that. Anything more, and you are abusing the comm, brushes, springs and magnets, AND not getting any power on top of it. An arcing motor will stress out everything in the system and not produce as much power as one that is properly maintained.

[Eau Rouge]

I know you probably aren't racing, but motor maintenance is the key to long life and high performance—even if you're just screwing around in a parking lot.



Then again, I got tired of this motor maintenance labor and converted all of my race cars to brushless. Little or no maintenance, and no need for a motor lathe at all. For backyard bashers, they are even nicer.

[MONSTER]

Ok. Ive cut the Comm and Installed New Brushes and Springs (REAL LUCKY I just happen to have some). Now, for Break In, I have some article excerpts (sp?) that suggest hooking up a 4-Cell Pack straight to the motor for this. I just made one and charged it up. How long should I let it run?

If any of you have "better" Break In routines, I LOVE to hear them.

Youve ALL been GREAT help so far. THANKS!!!

[Eau Rouge]

5 minutes on 2 volts (I use 2-cells or 2v on my TurboCharger). Oil the bushings or bearings, and a drop of Tribo or other break-in drop on each brush, and let 'er rip.

I also will take a small file and put a small flat on the leading and trailing edge of the brush before re-assembly.



I may not always have the best batteries, and I'm not that great of a driver anymore, but I ALWAYS have motor.

[Whiskers]

I can't remember where I read it (or even if I remember it right), but Mike Reedy was quoted as saying you only need to break in the brushes for 30 seconds.

[templeofspeed]

I can't remember where I read it (or even if I remember it right), but Mike Reedy was quoted as saying you only need to break in the brushes for 30 seconds.

...and then hand the motor back to Mike Reedy after your four minute run... repeat as necessary.

[MONSTER]

The Results are IN. I broke the 4-Pack into two 2-Packs (hes not dead, I have 2, hehe....Lord I apologize for that there, and be with the starving Pygmys in New Guinea....). I didnt lube the brushes for Break In though. Is that bad? I DID flatten the edges of them (I always do that). I set timing at 0, and let it run 5 minutes. Afterwards, I hooked it up and let it run slowly while I "played" with the Timing. The closer to 0 I got, the FASTER it reved. Being the "Technological Chicken" that I am, I went with approx. 12*.

It is CONSIDERABLY better, but I expected a bit more from this motor. Reedy Flash Point Quad Magnet 15x2 ("allegedly"), geared 87/20 with GP3300 SideXSide (sitting a couple days since charge though). The Torque seemed good, but I really thought I would see more Top End. No noticable difference from what Ive seen from a "Generic" Stock Motor geared 87/18.

What should I expect from this motor? It seems to be the same armature as a Buddys motor of the same make. If I read correctly, I can adjust the timing to as low as 2*, but no more than 15*. Correct? I'll try that next.

[MONSTER]

5 minutes on 2 volts (I use 2-cells or 2v on my TurboCharger). Oil the bushings or bearings, and a drop of Tribo or other break-in drop on each brush, and let 'er rip.

Im soo slow. I just noticed this statement. Are you saying I could just hook the motor up to a my Charger (Super Brain 969) and set it at 2 volts (I think it'll go 2. I KNOW it'll do 3. would that be ok) and use that for Break In?

PS: No one addressed my post before this one. (hint hint).

[teshreve]

The only purpose for break-in is to seat the brushes. That is so the entire face of the brush touches the commutator (or at least the part you want to touch the commutator - in the case of special brushes where material has been removed).
The purpose of that is so the motor acts consistently and does not change during a race while the brush faces become seated.
That said, motor break in is pretty worthless in my opinion.
Here is how I break in brushes: I install them.
If I am really concerned, I practice for a few laps prior to the race. They seat in actual use in a matter of seconds (depends on the motor and the brush, but you get the idea).
If you are not racing, there is no purpose for break-in at all.

[Eau Rouge]

I use a small plastic fan on the arm shaft of my motors to give some resistance on break in. I don't know anything about your charger, so I won't say what you can or can't do with it, but my Turbo35 has a motor break0in feature which is what I use.

300 seconds at 2v with a fan load is all I do for break in. I use Zubak Speed Juice for break-in drops, but most drops will work. They are all some sort of concoction of kerosene and other lubes.

As for the Reedy comment, I've never seen ANY brushes broken in at the 30 second mark—ever. Some might need more than 300 seconds, but not usually anything worth putting in a race motor.


Motors are a black art. Brushes are a small part of them. Springs are HUGE. You can make a single motor do many different things just by varying the tensions of each spring. On my race stocks, I almost always run a stiffer spring on the (+) side, too. Brush size, shape, cut, compound all play a factor in performance.

And here's the big one. All motors have a sweet spot, and if you are off on the gearing, you'll never see it. Gearing is the single most important thing you can do for an electric motor, because if you're not geared right, I don't care what you're doing to the motor, it will seem flat and lifeless.


If your Reedy Quad truly is a 15T, then 2t different from a stock motor is probably not even close on the gear. I know the quad mags can have a narrow gear window, too, but when you hit them, they can scream. I found that my 19T spec Quads loved a lot of gear, and I was generally gearing them 6-8 teeth (64 pitch) above what other guys were running in their 19T motors.

It's generally a lot of trial and error, especially with a motor that isn't generally used by a lot of people for racing purposes (it's easir to get a baseline rollout or ratio for a known motor).



I'm sure I just confused you more and made it worse...

[Eau Rouge]

If you are not racing, there is no purpose for break-in at all.

That is true. If you aren't racing, set it and forget it. Clean the motor every once in a while and replace the brushes and springs every 12-15 battery packs run through it, and you should be fine.



I assumed that if you have a motor lathe, you are much more serious than a backyard hacker, but you never know.

[MONSTER]

I assumed that if you have a motor lathe, you are much more serious than a backyard hacker, but you never know.

Im sure I would be considered a "backyard hacker", BUT, I AM trying to start a R/C Track/Business in our area. Maybe I havent mentioned it here (its in my sig on most Forums), but my "LHS" is TWO HOURS AWAY. Thats the reason I said I was REAL LUCKY I had some brushes and springs. Hence, the reason I ask so many questions, rather than just "try out" things. If I mess up something, even cheap brushes and springs, I'll be out of commision until I can order and recieve the parts I may have ruined.

Plus, I have the same "Wife Problem" as some of the rest of this forum....and Im Cheap to boot!!!

[Whiskers]

I'll back up my comment, by saying that I got that quote (and I just checked) from the on-road brush pack that was included with the MR. line of motors, and the on-road brushes are already contoured (roughly) to the comm.
I would have to check my off-road brush stash to find out if they're contoured.

I will say this, when I got my hands on the first Reedy MR. series motors, I thought they were great, and other than some I had in my box, I swore off all other manufacturers.

[teshreve]

The Mr. series includes a few different lines, including my favorite: Sonic and Sonic2
I'll tell you right now, the large comm Sonics are CRAZY durable, don't give a flying crap about gearing, and survive the worst torture test ever conceived: a boat on silly voltage. If you have ever run a modern motor on 12 cells, underwater, you know what I am talking about...

To top it all off, they are stupid fast.