22 replies to this topic

[Edo]

Gentlemen
Could you explain me exactly what spring tension on brushes does and when it is recommended to lower or upper it? And does it have to do anything with available amps at the power pack?
Thanks a million
Kind regards
Edo

[TSR]

Hi Edo,
You need a certain amount of "push" on the brushes to avoid a phenomenon of "floating" where the electrical current is acting like your tires when aquaplaning. In pro-racing motors, this push has increased considerably since the Pittman days...
The Hersh Man and others here will be able to explain to you what kind of tension is actually needed depending on at what kind of resistance, or lack of, the motor is rated.

[Cheater]

Edo, Dokk's answer is correct but let me give you my feelings on this subject.

In general, brush spring tension is not critical, as long as you have sufficient tension to keep the brushes from bouncing or floating. When this condition occurs, excessive arcing at the brush/comm interface will quickly damage the commutator surface as well as the brushes. So the rule is err on the side of too much spring tension rather than too little.

The faster the motor, the more spring tension will be required to prevent the brushes from floating. Stronger springs will give slightly better braking, but rarely do racers add spring tension for this purpose.

Virtually everyone uses Champion light (red) springs, or their functional equivalent, on C-can motors of any type, from Contenders to X-12s. What this tells me is that there is very little performance to be gained from playing with spring tension levels.

My thoughts are that spring tension is not going to be a big issue for you on the tracks you run on. Just make certain that you have matched springs (i.e. giving equal tension) and that you have sufficient spring tension to keep the brushes firmly on the comm at all speeds.

[Edo]

Now we're talking
Thanks!
Actually I always think about vintage motors and how to restore them, especially when I need to get new springs since IF I put post protectors the old ones rarely reach from one side to the other without binding on the post.
So is there a definitive suggestion on which kind of modern springs and what brand I should get for my Mabuchis?
Kind regards
Edo

[Cheater]

Edo, the Champion lights, which are dyed red, are the standard springs for almost all 1/24th scale racers. They're all I use on any of the modern C-cans and 16Ds. They should work fine for your purposes so long as they fit the endbell properly, i.e. with the spring coil fitted onto the post the long leg reaches the hook and the short leg contacts the brush in the proper place.

[pbj59]

Supposedly, heavier springs can increase brakes a little, I've never actually compared though.
Roy

[proptop]

what do you guys think of putting (let's say) medium springs on after the comm gets a little worn? You know what I mean? Start with light springs and as the comm wears and gets "bumpy" (for want of a better term :mrgreen: or maybe 3 lobe cam like?) switch to mediums?

I'm not talking about high perf. motors or for racing obviously, just crutching an old motor that's getting a little tired until you get ta turning the comm.

Any of ya do that?

I normally use light springs and either Big Foot II's or Gold Dust brushes in just about all my motors.

[Prof. Fate]

Hi

If you need to go to mediums, what you need to do is retrue the comm instead.

Fate

[proptop]

Don't want to be accused of motor abuse! :shock:
Might have the motor protective people knocking at my door to take them away from me!

I have a comm lathe for R/C car motors...probably oughta break down and get one for my slot motors too...

A magnet zapper would be really cool...but a little pricey (sp?)

[Rick]

The arm lathe and zapper both paid for themselves in a rather short while, probably the best investment I made. and pssst, I just happen to know a guy that knows a guy that makes zappers. heheheheeh

[proptop]

Im in Rome...sort of half way between Schenectady and Rochester...ea. one is about 100 mi. from me.

The one in Cortland...is that Speedy's? I heard they closed awhile back, but then I heard they just moved somewhere else...
Cortland is probably about an hour and a half to two hours away...

Sorry Edo...don't mean to "hijack" your thread...

I use light springs on everything.
I have some vintage motors that have the green comm body? It doesn't look like they would be able to be turned, hence the med. spring question...but I have never been able to find med. springs for those motors anyway...

[Edo]

So,
in the end: the light Champion red springs are what it's suggested for vintage Mabuchi post protected motors?
Please confirm, you people in the know!
Best regards
Edo (would be MPP activist)

[proptop]

Edo...if you can find 'em, the older Mura "over and under" springs IMO work better. They are wound identically so there's no left or right. They're getting hard to find now though.
(Mura switched to both springs on top sometime in the mid 90's when they re-designed the can and end-bell)

I made a few sets of spring post protectors out of brass tube. The older Mura springs have a nice long "tail" on them and work great.

The Champion red dyed lights are a lot more common nowadays though...so they're probably your best bet?

[NJ Racer]

Springs and Brushes are excellent replacements for your 16D equivalent vintage Mabuchi. Parma lead wire works well too.

[NJ Racer]

...they are junk, but apparantly so are the motors Proptop is referring to. I must have a 100+ pair of brushes, springs and leadwire that I stripped off every Parma sealed motor I ever bought and replaced them with Pro Slot brushes, Champion light springs and TQ leadwire.

Anybody want some?

[proptop]

Yeah Ray, most of these motors have been sitting in a shoebox for almost 40 years...

Probably just keep 'em as they are...momentos...
My brother said in the mid-60s, they used to slap a pair of stiffer springs on as a crutch during a race or if they wanted to get a little more out of it before it either went to ship or got the comm turned.

[proptop]

Forgot something...
Why doesn't anybody use the stock Parma brushes? Are they too hard, too soft, or what? I haven't run that type of motor in years...

I picked up a few (used) newer 16Ds and S16Ds in batches of misc. stuff off eBay...what's wrong with using the 36D size Parma brushes in them? The springs do look pretty wimpy.

I use Gold Dust brushes or Big Foot IIs in all of my 12s, 15s, and 20s...and champ light (red) springs.
Used to use RJR brushes when I raced a lot more back in the '90s. I think they had silver in them, but don't know if ya can get them anymore.

[proptop]

Yeah Bill, that's what I figured...thanks.
In my "spare" time when I ain't fiddle-fartin' around in the basement trying to figue out the track details, I like to work on motors. My brother gave me all his old stuff years ago...now, I kinda have him getting interested again...