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  1. #1
    RC Racer
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    Brushed Mod Motor Questions

    I recently picked up an open-endbell motor and have a few questions. Since that is a piece of equipment that was common for vintage electric vehicles, I figured this was the correct forum.

    1. I've heard that taking an eraser to the commutator and brushes is a good way to clean them after using motor spray, but I can't get any erasers down to the comm. What do you recommend?

    2. I took the springs off my brushes and took them out, and got a few photos. This was before cleaning. Does this look normal?



    3. Is the black coloration bad or does it mean anything at all?

    4. I would just like to check that the motor is properly timed. Is this correct for 0 degrees?


    5. Do you have any recommendations or advice for a first time owner of an open endbell motor? Are there any other photos you want me to take?
    I might have addicted my friend to RC. O.o

  2. #2
    Traxxas Employee nixhex32's Avatar
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    You can actually pull it apart and Clean the comm with it out of the can. Just remember the orientation of everything. Or look online for a comm cleaner tool. They used to make them, about 2-3" long with one end that fit down the brush hood.
    TRX4(lots of mods), TCP(will stay with me), Custom Summit, GTP Fiero(in rebuild stage), "My Summit" pic is posted in the Summit gallery........and some other things.

  3. #3
    Traxxas Employee nixhex32's Avatar
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    You could also look for a comm lathe but for just one motor it probably isn't worth the money to you...... unless you find a super cheap one.
    TRX4(lots of mods), TCP(will stay with me), Custom Summit, GTP Fiero(in rebuild stage), "My Summit" pic is posted in the Summit gallery........and some other things.

  4. #4
    Traxxas Marshal
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    Those brushes look like they have a lot of life left in them yet. Some discoloration will be normal due to wear and heat. As for the timing, it's hard to tell from that picture. Part of me wants to say that that's 0 degrees of timing, but another part wonders if it's actually negatively timed. I'd need to see a clearer image to know for sure.

    I enjoy working on old brushed motors. I even went so far as to get a lathe for truing the comms many, many years ago!
    "Happiness depends upon ourselves." -Aristotle

  5. #5
    RC Racer
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    Thank you both for your help! I'm glad that it looks normal, because I have no experience with these.

    nixhex32, you mentioned taking the armature out. How do I do that?

    With all my research on the internet, I couldn't really figure out what negative timing does. Do you have an answer?

    I was not concerned about brush life, because I had about 7 runs and break-in on the motor when I took those pictures. I do not think that I will be getting a comm lathe, because the cheapest one I have found anywhere was 300 dollars. I'll work on photos for you all of the endbell from a few different angles. Thank you again!
    I might have addicted my friend to RC. O.o

  6. #6
    Traxxas Employee nixhex32's Avatar
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    There should be 2 screws that hold the end bell on. Just remove those and the internal ring, then the armature pulls out. Keep an eye open for any spacers or washers though.

    I wouldn't play with the timing to much, not without a dyno for it. MAKE SURE to note the timing if you take the motor apart.

    Yes the comm lathes are not cheap, I still have one from the 90's when I used to race. Now its just a reminder of the old days.


    Quote Originally Posted by Is_It_Broken? View Post
    Thank you both for your help! I'm glad that it looks normal, because I have no experience with these.

    nixhex32, you mentioned taking the armature out. How do I do that?

    With all my research on the internet, I couldn't really figure out what negative timing does. Do you have an answer?

    I was not concerned about brush life, because I had about 7 runs and break-in on the motor when I took those pictures. I do not think that I will be getting a comm lathe, because the cheapest one I have found anywhere was 300 dollars. I'll work on photos for you all of the endbell from a few different angles. Thank you again!
    TRX4(lots of mods), TCP(will stay with me), Custom Summit, GTP Fiero(in rebuild stage), "My Summit" pic is posted in the Summit gallery........and some other things.

  7. #7
    Traxxas Marshal
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    $300 is definitely a bit much. I bought one from Trinity around the time BL motors were gaining traction new for maybe half that.

    Negative timing is almost always going to be a bad thing, resulting in less performance, more heat, and more wear. Negative timing is only really useful in situations where you'd be running the motor in reverse rotation. I typically run between 6-12 degrees of advanced timing on motors with adjustable timing for what it's worth.
    "Happiness depends upon ourselves." -Aristotle

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