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Old 02-27-2009, 03:11 PM   #1
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Default Problem with stock RC18T. ESC maybe?

My buddy has an 18t and has been goin through motors like batteries. the stock motor died after a couple of months and put off a pretty bad smell... like it was burnig but no smoke. He bought a new motor and that one lasted maybe a day, again with the smell. his third motor went the way of the other two only minutes after breaking it in and during the break in process it made that smell. He broke all of them in (except for the stock one) by flipping the car upside-down and turning up the throttle trim a bit long enough to kill a fully charged battery.

So could he have a faulty ESC? Were wondering if the esc is just throwin too many volts to the motor, except it isnt really pickin up any extra speed so we don't know what to think. I don't think the ESC has been getting hot or anything.

Thanks for any help!
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Old 02-27-2009, 03:17 PM   #2
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It could also probably be the gearing. I have a rc18b and i smoked the motor, got help and found out that I had the gearing way to High(wrong). You should also consider going to brushless, they last a lot longer and you can run lipo.
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Old 02-27-2009, 03:38 PM   #3
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hes got the stock pinion in it but I guess that could be too high for his back yard. Although mine is exactly the same and I'm having no trouble. Also, I don't see how the gear ratio could affect the motor when its flipped upside-down bein broken in. but I guess its worth a shot.
these are kinda just toys for us right now... little cars that we can use for experimentation and learning damaging lessons on instead of our more expensive cars. We'll get to lipo eventually and probably even set these little cars on fire with them but we've got a lot more to figure out before we switch to lipo.
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Old 02-27-2009, 04:02 PM   #4
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If your using a standard sized batter pack, it is unlikely your ESC is sending too much power to the motor. With 5 cells, there's only a little over 6 volts at full charge.

I would look at the drivetrain without a motor. Does it move freely? Compare it with yours if you need a reference. Also, make sure the mesh between spur & pinion has a little play. If it doesn't, there will be excessive drag on the motor. Check it in small increments all around the spur, as most spurs are not true.

One other odd thing..... you didn't by chance replace any screws, did you? Screws mounting motor too long? Screws mounting drivetrain parts somewhere? (This would show up with a bound up drivetrain.)

You could also swap ESCs with yours, to prove the ESC is not the problem.

My suspicion, a drivetrain problem. Maybe a blown bearing, or dirt or something in the front/rear diff.
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Old 02-27-2009, 04:05 PM   #5
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gear mesh could be too tight maybe?
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Old 02-27-2009, 04:11 PM   #6
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Quote:
Originally Posted by groundhogg View Post
If your using a standard sized batter pack, it is unlikely your ESC is sending too much power to the motor. With 5 cells, there's only a little over 6 volts at full charge.

I would look at the drivetrain without a motor. Does it move freely? Compare it with yours if you need a reference. Also, make sure the mesh between spur & pinion has a little play. If it doesn't, there will be excessive drag on the motor. Check it in small increments all around the spur, as most spurs are not true.

One other odd thing..... you didn't by chance replace any screws, did you? Screws mounting motor too long? Screws mounting drivetrain parts somewhere? (This would show up with a bound up drivetrain.)

You could also swap ESCs with yours, to prove the ESC is not the problem.

My suspicion, a drivetrain problem. Maybe a blown bearing, or dirt or something in the front/rear diff.

We've talked about swappin ESCs we were kinda trying to avoid doin that, partially out of lazyness. I'll go ahead and check out his drivetrain for binding and bad bearings. I'm assuming he's allowing a small amount of play between the gears but I'll also double check that. As far as aftermarket screws go, thats a no. all original hardware.
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