# shimming motor arms



## joseoval (Jan 1, 2004)

will this affect a motor if its centered or pushed to one end more???????????/i've heard that each is better than the other


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## Mac The Knife (Jul 23, 2002)

I've always heard that you want the armature to be in the center of the magnetic field,,,,, Why else have strong magnets if you're going to run it off center? besides, it seems to me that it would cause the bearings to wear out sooner.


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## Slider (Dec 7, 2003)

you want it to be as equal as possible on both ends.remember the arm is going to be slammed back and forth on accel and decel.keep it as close to center.My .02 worth


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## joseoval (Jan 1, 2004)

my thought is for it to be centered also but i saw 2 motors be centered then offset toward the endbell and DYNO results were better on rpm and eff. on a fantom so why is this????????????


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## b4wizard (Sep 27, 2003)

The motors do seem to run better when they are centered. But if you are going to do that, you should also align the brush hoods. Trinity makes a great tool for this.


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## Luckyman4 (Sep 26, 2001)

joseoval said:


> my thought is for it to be centered also but i saw 2 motors be centered then offset toward the endbell and DYNO results were better on rpm and eff. on a fantom so why is this????????????


I'm no motor guru but I think I know ... moving the armature off center will reduce the effect of the motor's magnetic field - which will lower torque and increase rpm [and due to the characteristics of the fantom dyno will show as more efficient]. This is maybe a good trick to use on a torquey motor like a P2K if you want more rpm and less torque - or depending on the motor and the track size probably a good oval racing tip [somewhere you don't need torque, high speeds are maintained throughout the race]. Bad idea for offroad though I would think ... maybe some motor meister here can confirm this?

-John


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## joseoval (Jan 1, 2004)

I do run oval and i tested another motor today (epic binary)both ways center and shimmed toward endbell no difference an torque or runup but the rpm went from 24300-25200 and the watts went from 64-66 as far as i know this should.........be a killer motor on paper anyway track test this sat.what is anyone getting on binary runup mine was 5.0 i consider that slow


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## EddieO (Sep 19, 2003)

Get a copy of Big Jim's Motor Book of this website. I believe there is a link on the main page. There is a great detailed section in there on how to center the arm properly....along with a ton of other great info.

Later EddieO


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## DLM (Mar 10, 2004)

EddieO; there is a section and tuning motors but is for individual motors. There is no general rule written in concrete and would like to be corrected if i'm wrong. I was taught to center brushes in middle of comm. I have found like today on an older motor, i shimmed and the magnetic field kept pulling the arm away from endbell till i put enough shims on the endbell side till i had less than .006 play. I believe each motor is a new ballgame on shimming. I would like to hear more info and the exact page in his book which i have. Thanks!


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## DLM (Mar 10, 2004)

Slider; i have a question for you! How do you know if you have center? Are you referring to putting arm in can and then putting endbell on and no shims and let the mag. field find it's place. This something for Big Jim to answer cause it is to vague and is very important. Thanks! Good subject!!


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## dgraham225 (Dec 6, 2002)

keep it unshimmed at first. put it all together, spin the armature with your fingers and pull the arm to either end. if you have any significant amount of slack, shim it. do this for both sides. let the armature find its center of the magnetic field.


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## DLM (Mar 10, 2004)

Page 21 in Jim Black book. It takes time but well worth every second it takes. Thanks for the reply, it helps clear the fog, thanks again! have a good day!


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## DLM (Mar 10, 2004)

I would like to add to the gentleman about natural lay of arm. Measure with arm,can endbell and measure from pto end to end of stem and put in extras ( shims ) and check measurement for long or short amount of shims. Thanks for info people, it sure helps!!


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## tcguy808 (Dec 2, 2003)

on the brush hood tool thing...niftech makes the best...it checks the the alingment from the bushings...onky problem is it was 44 bucks when i bought it but worth it....


my $.02


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## dgraham225 (Dec 6, 2002)

I wouldnt say it is the best. not by a long run. alot of different hood tools use the bushings as a reference point, but that only aligns them to each other. they have to be individually aligned afterwards by monitoring the brushes' wear pattern. 

I would say the Big Jim alignment bar is the absolute best. it has the tightest tolerances of ALL tools and is made out of a high quality stainless steel. great stuff!


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## weee37 (Mar 27, 2002)

sorry i dont agree with any of big jim's theorys on motors or his motor tools.  

and niftec does make a top notch hood alignment tool.


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## rctom243 (Jul 13, 2003)

I just got a brush alignment tool from www.rc4less.com It is made by Wolfe Motorsports. Has a nice anodized handle and is strong enough to tweek the hoods to get the brushes running in the center. And at $12.95 it sure beats laying out $44.00 for the other one.


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## EddieO (Sep 19, 2003)

His motor designs have a quite a few world titles under their belt.....not to mention numerous national titles....

A few of us talked to Mike Reedy at snowbirds.....his alignment theory was pretty much identical to Jim's.....

His tools are trick...........a lot of the top guys at snowbirds had one....

Aligning your brushes to bushings/bearing is pointless....you need to account from brush cocking in the hoods......I have the niftech tool....its junk in my opinion....my racer's edge alignment bar for $10 works much better than it does....the Big Jim unit or the KT Hobbies unit are the best two on the market....I have them both and they are both quality made tools that work great.

Jim Deiter is now posting here on these boards, feel free to ask him about brush hood aligning. I watched him at snowbirds.....and he certainly wasn't aligning hoods with the bushings or directly across from each other.

Personally, I think people just disagree with Jim because they don't like his attitude.....most people just deal with it and learn. Reedy would not of hired him to help develop the KR or the Quad 19t if he didn't know what he was doing....the only reason they let him go was because the projects were done and now they are working on some brushless techonology....ask Deiter if Jim knows what he is doing....

Later EddieO


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## EddieO (Sep 19, 2003)

I just checked out the Wolfe tool....looks like a decent unit....

And they give pretty decent advice in their description....

"Here is an outstanding tool to adjust your brush hoods. Long enough to reach across the endbell and align both hoods exactly straight. Then after running your brushes check where the comm is wearing your brushes. Then use the alignment tool to "tweek" you hoods to align the comm to run in the exact middle of your brushes. Super strong tool. A must for your pit box."

Thats pretty much what Jim tells you to do.....



Later EddieO


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## ovalnator (Sep 26, 2001)

EddieO said:


> I just checked out the Wolfe tool....looks like a decent unit....
> 
> And they give pretty decent advice in their description....
> 
> ...


can you provide a picture of the KT hobbies alignment tool?


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## EddieO (Sep 19, 2003)

www.kthobbies.com is where I got mine.....

I still like the Big Jim unit better though, its made of stainless steel and has a lifetime warranty....and it does come with a shaft to align the bushings and hoods if you want.......

I have no clue how to post photos.....everytime I try it never works right....

Later EddieO


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## RC4less (Oct 9, 2001)

*Wolfe Alignment Tool*










Here is a picture of the Wolfe Tool. 

BT


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## ovalnator (Sep 26, 2001)

EddieO said:


> www.kthobbies.com is where I got mine.....
> 
> I still like the Big Jim unit better though, its made of stainless steel and has a lifetime warranty....and it does come with a shaft to align the bushings and hoods if you want.......
> 
> ...


can you email me one?


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## EddieO (Sep 19, 2003)

I can send you one of jims, I can't seem to find my photo of the KT....I will look for it.

Send me yer email at [email protected]

Later EddieO


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## eri3f0g (Feb 12, 2004)

*Reviving another old thread*

Hey guys,

I'm in the market for a brush hood alignment tool. I've finally invested in a lathe and now I feel that I can start my journey into tuning motors. I've got a couple of questions that I'm hoping you can help me with.

First off, My background is limited on motor tuning. I occasionally cut the comm on my motors and clean the motors before each weekend of racing but really no maintenance during the raceday as some.
I've never shimmed my motors but I've just picked up some shims to start that process.

Questions:

Brush hood alignment tools: What's good and what's not. Even though I hate to state this, cost is an issue and I'm looking for the best bang for the buck. I don't want one that will make me go out and buy a better one in six months. Any links or references are greatly appreciated.

Big Jims Book: Being a newb to real "hands on" motor tuning, is the investment in this book really worth it? Anyone know of a site that sells both the book as well as a hood alignment tool so I can save on some shipping?

Motor Shims: I've seen pheno....(spelling?) shims, teflon shims, and metal shims. Pro's and cons to either?

Thanks all for any help. I really appreciated your replies so please, I encourage you to add your 2 cents as the more replies the better I can average the responses.


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## pepe (Sep 29, 2001)

eri,

You can go to motortuningsecrets.com and it will get you started in the world of motor tuning.As much as anyone tells you,always remember EACH AND EVERY MOTOR IS DIFFERENT.


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## eri3f0g (Feb 12, 2004)

thanks much, a new site to read... I haven't stumbled across that one.


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