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Old 01-20-2006, 09:46 AM   #46
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Eddie I have a question for you. Why is it that everyone swears they can only get 2-3 runs on brushes. I know there are exceptions but I find that the longer I run the brushes, the better the motor is. Obviously you reach a point when it starts to go down hill. But if you had a bell curve showing where your motor is the fastest I believe most people say its 2-4 runs when I say it's 4-8. I know there are a million variables but if your brushes are not discolored then they are still good... I guess I am old school. Perfect example....last week I ran a C2 that had F brushes in it. It had about 10 runs on it...the 11th run the motor died...it needed a rebuild. but the 6-10 runs were faster than ever!!!
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Old 01-20-2006, 05:33 PM   #47
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Quote:
Originally Posted by Bob Barry
Eddie I have a question for you. Why is it that everyone swears they can only get 2-3 runs on brushes. I know there are exceptions but I find that the longer I run the brushes, the better the motor is. Obviously you reach a point when it starts to go down hill. But if you had a bell curve showing where your motor is the fastest I believe most people say its 2-4 runs when I say it's 4-8. I know there are a million variables but if your brushes are not discolored then they are still good... I guess I am old school. Perfect example....last week I ran a C2 that had F brushes in it. It had about 10 runs on it...the 11th run the motor died...it needed a rebuild. but the 6-10 runs were faster than ever!!!
The brush wear will depend on amp draw and Rpms.
More Rpms the faster the brushes will wear.

Motor timing and gearing has alot to do with it also.
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Old 01-20-2006, 05:43 PM   #48
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Quote:
Originally Posted by Bob Barry
Eddie I have a question for you. Why is it that everyone swears they can only get 2-3 runs on brushes. I know there are exceptions but I find that the longer I run the brushes, the better the motor is. Obviously you reach a point when it starts to go down hill. But if you had a bell curve showing where your motor is the fastest I believe most people say its 2-4 runs when I say it's 4-8. I know there are a million variables but if your brushes are not discolored then they are still good... I guess I am old school. Perfect example....last week I ran a C2 that had F brushes in it. It had about 10 runs on it...the 11th run the motor died...it needed a rebuild. but the 6-10 runs were faster than ever!!!
i have the same conception...i run Putnam green/blue combination for up to 30 runs and the motors is as fast as ever...dont they say they only last a couple runs?

the last F brushes i ran are still in the motor and have about 8 runs on them and they are still producing some decent power

the 767's and 4499's i feel fall off quicker in my experiences

this is all in Monster stocks
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Old 02-16-2006, 09:55 PM   #49
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Originally Posted by EddieO
I can tell you at cleveland, in Mike Dumas's 2nd place finishing car, we ran the 3.8 MR, which is the 4th stiffest of the MR springs....whenever we went to the stiffer, the motors had too much RPM....dumped and sometimes spun up to high and got knocked out of balance....
got 3.8 MR spring? i though on MR only have 0.35mm and 0.32mm for MR spring only got 0.38mm MR spring? where can i get it?
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Old 02-17-2006, 02:02 AM   #50
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I think "I'm going slightly mad" after going through this thread!

Let's see what others have to say about motor springs:

Trinity
http://www.teamtrinity.com/shop/springs.html
Green : Medium Good for general use
Red : Medium / Heavy Good for general use
Medium / Heavy Good for Touring on a very large track
Purple : Heavy Great for hard working motors like Touring & 4wd Truck
Silver : Extra Heavy Great for hard working motors like Touring & 4wd Truck

Team Orion
http://www.teamorion.com/products/mo...ss.asp#Springs
Alter the powerband and characteristics of your motor by changing your motor spring tension. Try a little stiffer spring for more torque and a little softer for more RPM.

Team Associated / Reedy
http://www.teamassociated.com/shusti...motorparts.htm
Simply put, harder spring pressure increases friction and slows down the commutator. In general, the less tension placed on the brush, the more RPM (top speed). The more tension, the more torque (faster acceleration). Spring tension is measured by ounce rate. The lower ounce rate generates less pressure than a higher ounce rate. Choose a lower ounce rate for slightly more RPM, and a higher rate for more torque. However, harder pressure will hasten commutator wear.

DCmotorsports
http://www.dcmotorsports.net/tc.shtml
Our Touring Car line of motors include winds from 7 to 12 turns, singles and doubles, using the base tear downs. Our double winds feature a Variance Split Wound armature, combined with smaller than average wire gauges these motors generate the quickest Spool-Up times possible, and provide the most torque coming off the coroners, exactly what’s need for Touring Car racing here in the Unites States. These motors are tuned with an aggressive motor setup, featuring High Silver Brushes, Heavy Springs and Advanced Timing for maximum performance through out a 5 minute run…

Big Jim
http://www.rccars.com/forums/showthread.php?threadid=8
The more arcing between the brush and the commutator, the more spring tension is needed to counteract that arcing. Factors that cause the motor to arc more and therefore more needed tension are: excessive timing, low winds, out-of-round commutator, heavy loads (tall gears, heavy cars, lots of traction), motors with electrical problems, etc.
It's always better to "over-spring" than "under-spring".


Ok, that's all I could find in a few minutes of online search. I allways thought that the heavier the car, the heavier the motor springs to increase punch. Now, after reading this thread, it doesn't make sense anymore. Are the above motor tuners wrong? They all seem to claim that heavysprings=torque, light=rpm
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Old 02-17-2006, 02:18 AM   #51
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No, the heavier the car, typically the more load that is placed on the motor.....which is what causes brush bounce, which requires a stiffer spring to prevent it....

Search Big Jim's forum, you will find him say the same thing about springs that I do....I argued with him before on it....the guy is right. Why Orion and Reedy put that on their site is beyond me.....it's simply not correct...

Later EddieO
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Old 02-17-2006, 02:37 AM   #52
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Ok Eddie, thanks for the tip. I allways thought that going "hard" on motor springs for touring, was a safe thing to do. Now there are even more tuning options to consider...
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Old 05-29-2006, 06:48 PM   #53
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Hi, I have a couple of motor questions that have probably been asked before, but any advice appreciated.
( 1 ) Why can't you run the brushes of a motor in by placing the motor shaft onto an electric drill and gently bed the brushes in ?

( 2 ) What is a good brush to run in a Reedy Quad 19t for offroad Truck ? the originals seemed to wear fast.
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