# wizzard com brush questions



## tonesua (Jul 1, 2006)

I bought wizzard comms for a my Tjets. I put it in one of my xmas tree arm sand within a minute or two it smoked and burned up inside the chassis. I cleaned up the arm and it ohm'ed out okay (16ohms avg). I noticed that the wizzard com brushes are pretty tall. I didn't feel anything binding. I had to get another chassis as the burn marks melted the surface and therefore didn't provide for a flat surface. 

Other than brush spring tension, is there anything I should avoid or do to keep this from happening? I had some pretty average magnets in there (i don't have a way to measure them). I had almost the same thing happen when I put the same arm in another chassis. 

I have a few of those multi colored xmas tjet arms, and I like how they run. They usually come from chassis that have been well played with. Should I use flatter coms? Or flatten the wizzard ones with a sanding block?


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## 88T-BIRD (Jan 14, 2000)

Is there oil on the armature commutator? If so the wrong kind can short out between the brushes causing a lot of heat that will melt the chassis.


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## tonesua (Jul 1, 2006)

88T-BIRD said:


> Is there oil on the armature commutator? If so the wrong kind can short out between the brushes causing a lot of heat that will melt the chassis.


Yes there was a bit on there. I cleaned it out with a little Super Contact cleaner.


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## Boosted-Z71 (Nov 26, 2007)

Excess oil, too strong of brush tension & a com plate that has already started to burn between the segments will all lead to the scenario you described.

Boosted


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## Bill Hall (Jan 6, 2007)

There's a lot of variables. 

For stock application I prefer Thunder Brushes. 

Dont get me wrong, Wizards are great too; but they should be used in combination with other go fast parts, AND they would definitely not be my first choice in a set up with stock magnets and a 16 ohm Christmas tree arm.

Straight from the hip, based on your intel that the poor thing died minutes later; one would presume that the tension on the comm was too high due to the taller installed brush length of the Wizards. The first clue would have been no coast off throttle, immediate heat build, and twitchy track behavior. This case is providing there was no other excessive friction in the drive train. 

In reading a bit deeper you offered that you noted the same behavior from this motor in another chassis. Was there Wizards involved at this time ....or no?

Most t-jet arms are adequate for their assigned task. Few are holy grail. Many are incredibly average performers....and of that "many" a certain amount commit suicide by letting the smoke out of their wires and there isnt always an obvious explanation.

As a rule, I always pre-run, test, break in... whatever the heck you want to call it, unknown armatures in an old slave chassis that sits on my work bench. It has Tuff ones magnets and Thunderbrushes loaded to go, then held in place with an old spare arm and gearplate. The pick up shoe hanger tab is busted off, the rear axle holes are porked, and the rear screw apron is split....it doesnt have any other purpose in life except to take the brunt of any test detonations. Lube it up, let it run in til the brushes clean up, pipe it up, apply some load, test some other magnets; and generally see whats up BEFORE you load it into a perfectly good chassis.

From this test mule, I can determine what needs to be done, if anything at all. Based on the performance response during testing, I'll have a really good idea of what kind of build I can create with the armature. I rate them in roughly four groups. Five if you count DEAD as a category. Good-Bad-Ugly, and Singers. 

Singers are the naturally balanced units that pipe up nice and smooth with good throttle response. Good means that they respond well to input but require balancing. Bad means that although they work, they neither respond well and would require balancing anyway. 

Ugly means that there numerous issues, like scarred or de-lamminated comm segments, severly off centered or loose comm plates, burnt undercuts, scorched or loose windings, bad solder, boogered shafts.

A finally we comm....er ....come to the phenomenon where the arm may run average or good with no load and when put into loaded service the performance drops off sharply and things heat right up until they fizzle. I call them aneurisms.

Ohm this, measure that...visit a fortune teller; there is no substitute for a proper bench test or the feel you naturally acquire from doing it repeatedly.

Hope this helps some


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## alpink (Aug 22, 2010)

well said and I glean a few ideas for my future building techniques. thank you


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## slotking (May 27, 2008)

I disagree!

I setup various classes of t-jets, and all did use wizzard or slottech brushes.

I have always maxed the brush tension because I run with a lot of built in brake. The brushes barely fit in the holes.

I would say you may have crap in the comm slot. to much brush powder(crap) in the slot will short and cause a problem.

Some oils will do the same and others will still let the car run fine.

my fastest fray car has a 18ohm Christmas tree arm with huge tension.
my fastest Greenbrier car has a 6ohm arm with huge tension.

which I forgot to say, tension to soft will also cause a problem.

if you want to send me the car with a few parts, I would be happy to set it up for you to show you what i mean


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## slotking (May 27, 2008)

btw, height in the brush hole also does not mean it has more tension than a brush lower in the hole.

there are tweaks 1 can do to up the tension of the brush spring


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## Bill Hall (Jan 6, 2007)

Well tonesua,

I'm sure you recognize that there is more than just the comm grinding, balls to the wall "I'm a pwetend wace cah dwivah and never actually read the question" setting.

Let us know how things work out.


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## tjd241 (Jan 25, 2004)

Bill Hall said:


> I prefer Thunder Brushes.


Me too. :dude:


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## slotking (May 27, 2008)

but i did read your reply
hence my reply :wave:

High tension is not a problem unless something else is wrong.
"uls o i a sfrt jk"


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## 88T-BIRD (Jan 14, 2000)

I agree with SlotKing, I have never seen brush tension cause too much heat in a stock chassis, stock magnets, and 16 ohm arm. I have seen hundreds of burnt up chassis were the armature has a thick coating of the dreaded red oil.


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## tonesua (Jul 1, 2006)

*I heart this site.*

First of all, a mighty thanks to everyone.

Let me preface this reply with a few things.
In the grand scheme things: there's the right way to do things, and the hobby way. I kinda do this the hobby way: I learn by reading and doing, and you guys really help the learning curve. I mean, the epiphanies and "oh yeahs" come to me much quicker. I am learning the right way and it makes the hobby much more enjoyable in the few moments I get to steal away from the new job, the fairly new kid, and the honey dew lists... 

Having just returned to a working job after a year and half, I had some pent up "retail madness" in me. I ordered a buncha parts to piece together a few of the tjets and other sundry finds that I found "in the wild" through a Craiglist ad. I kinda had to catch up a bit with tires, and such). I didn't realize the Wizz's were taller.

I have used the Thunderbrushes with much success. I didn't realize the Wizz were the hot ones...So Bill is right. There wasn't much else hopped up on these things, aside from some Vincent rims.
Let's just say your answers are a part of the chicken soup of problems that I had:
1) the wizz coms are kinda tall; 
2}the carbon dust was mighty in the body; 
3)the magnets look to be afx's( unlikely issue)
4) There was oil on the comm, more than I care to admit


All the cars were a mish mash of parts that one finds in the wild, a veritable goulash of parts put together by our teenage selves to atain the speed of our dreams, until the drivers license came along. 
The good things:
I didn't feel any binding. In fact, this one felt well broken in. 
The arm still ohms out okay. 

I have one question: Should I find a donor chassis and try it with some thunders? I cleaned the residue and I don't see any scorching on the surface of the arm. Or will we have some Richie Blackmore "smoke on the water, a fire on the track.." once again?

Forgive me if you've addressed this issue. I have to reread your replies to get the gist of it.


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## slotking (May 27, 2008)

1> there is only ever the right way to do something!
a>but sometimes there is more than 1 right way

For me the biggest help i have is my VRP DYNO, I have tested stock t-jet brushes, the big old mura V cut brushes, various silver brushes, Thunder brushes, wizzard brushes, and slottech brushes.

My 1st move was to end up using the Thunder brushes, they provided the highest dyno readings. Then the wizz brushed came out, and the dyno reading were even higher! (note: some guys used 1 TB and 1 wizz)

getting the gear plate on was pain, because my brushes basically sit above the brush hole. 

I then tried out the slottech brushes, and wow, they made a even more speed. they are also tall, and sit above the brush hole.

There are 4 or 5 of us who all have the same super high brush tension, no burning at all, that about 25 - 30 t-jets setup that way.

carbon and oil in the air gap would most likely be te problem you ran into,

also sending you a pm


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## 88T-BIRD (Jan 14, 2000)

IMO the best way to check a running chassis for problems, is to use a amp meter. Take a good running stock T-jet chassis and measure the amp draw, that will give you a good ball part figure. Use the same voltage and test your chassis, if you see a big increase you know something is wrong.


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## slotking (May 27, 2008)

great point!!

I do that at times as well, i hook it inline with my VRP DYNO!
helps a lot
works with Inlines as well


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## Bill Hall (Jan 6, 2007)

Hey guys....lookit....it's that weird kid from grade school that thinks everything is a racing car. :freak:

It's clear the guy is just putting vintage junk. For the average Joe, drop in the Thunderbrushes and be done with it. A bump in performance, less slag than stockers, and gentler on comm segments than high zoop brushes.

It's NOT always about racing or speed to the inth degree. Sometimes it's just about subtler things like hedging your bets and conservation of the parts you do have.

Reading....AND comprehension....see? :tongue:


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## slotking (May 27, 2008)

tonesua 

sorry that some people have hard time with me because i race.
Just trying to help and clear incorrect information that was posted before.

the nice thing with racing, is i have good times with friends and meeting new friends!
the big advantage is meeting people a lot smarter than me who have thought me tips and tricks that apply to any t-jet use!
so the collector, hobbyist, putzer, or racer will all benefit from proper car care.


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## AfxToo (Aug 29, 2003)

For fun runners I tend to go lighter on the tension, like Bill said, but don't go too light or you'll get arcing like Mike said and that's bad news. That's why I always start with a clean comm and inspect it after running for a couple of minutes. When I clean the comm I always clean our the segment slots with a pointy toothpick. I also run a ballpoint pen lightly along the segment slots to make sure the plate edges are rounded. 

Oil on the comm is really bad news because it will capture the brush dust and make a nice conductive paste. This is just bad. Don't let this happen.

For race cars I run high tension, high strength magnets, sticky rear tires, lightweight body, and have removed as much friction from the chassis and drive train as I possibly can for 2-4 minute heats.

I try to stay away from stating absolutes when the reality is all about multiple variations. To quote racer Abe: " Some parts are are all right some of the time and all parts are all right some of the time, but no parts are all right all of the time. "


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