Getting the most out of your Brushed motor

[NobbySideways 113]

I'm in a championship that uses stock 540 silvercan motors, no mods allowed. I want to stress at this point that I wish to stick entirely to the rules; nothing outside the spirit of the competition (I can't stand cheating).

Has anyone got any tips for getting the best out of the silvercan? Gear ratios are not allowed to be changed, the can must not be opened. I figured keeping it clean (cleaning out with Isopropyl alcohol for example, and re-oiling any bearings I can get to), I heard something a few years ago about Commutator drops, is that snake oil or actually worth doing?

Thanks for any help you can give,

 

Jon.

 

[Mad Ax 9325]

I'm not a fan of "silvercan" control motors as they are so massively variable from new.  I forget who but I'm sure someone did a motor dyno comparison with a bunch of new and used silvercans from across the years and found them to have big differences.  I also think this is one of the reasons why Iconic went with the Team Powers Cup Racer motor as a control motor.

Also people have found ways to cheat with the silvercan by opening them up and changing the internals.  I suppose technically you could do this with any motor.  Popping down the local scrap yard and asking them to stick the motor on the car-lifting electromagnet probably isn't within the spirit of the rules either.

That said, you can bed in a new motor by running it at low speed in a glass of water.  IIRC some people had a 4-cell pack specifically for this back in the days of brushed racing, but I just used an ESC and a careful throttle hand.  Can't remember how long I ran mine for but a search should find something.

Otherwise as you have already said - oil the bearings with a proper liquid oil (not something WD40, which will dissolve the oil and increase wear), ensure your drive train is as efficient as it can be (correct pinion gap, correct amount of correct lubricant), use an efficient ESC (assuming you don't have a control ESC), minimise weight, make sure all your electrical connections are good, and drive smoothly.  If you can maintain a higher corner speed you'll rely less on acceleration.

[Wooders28 4723]

36 minutes ago, NobbySideways said:

Has anyone got any tips for getting the best out of the silvercan?

Try and find the best silver can you can find, as above, they can range from around 16k up to 22k rpm!

Couple of tips on this page, reverse break in of a new motor etc

 

http://www.rccartips.com/540-silvercan-motor-tuning.htm

[NobbySideways 113]

Brilliant, thank you. I had seen the water technique but another source (there seems to be a lot of conflicting info!) said that running in the motors is something that doesn't need to be done any more as its done from the factory. I suppose I could peer in and see how well they fit the commutator.

I don't really have the budget to buy a lot of them, but I will see if I can get the best out of this one. As mentioned, I'm not allowed to open it.

Some good advice and thinking points, thanks.

 

[WillyChang 1814]

2 hours ago, NobbySideways said:

I'm in a championship that uses stock 540 silvercan motors, no mods allowed. I want to stress at this point that I wish to stick entirely to the rules; nothing outside the spirit of the competition (I can't stand cheating).

Has anyone got any tips for getting the best out of the silvercan? Gear ratios are not allowed to be changed, the can must not be opened. I figured keeping it clean (cleaning out with Isopropyl alcohol for example, and re-oiling any bearings I can get to), I heard something a few years ago about Commutator drops, is that snake oil or actually worth doing?

Thanks for any help you can give.

Cheating means opening the can, tampering &/or changing parts... up to & including trying to get away with 20T motors in a chrome can. 

Everything else is... not cheating.  

540, where do we start:

Theres 2 main brands, Johnson & Mabuchi... pick which one you like better. Doubt any one is particularly superior (although T seems to imply the "540J" is an upgrade) unless you can find that famous 1990s vintage 4-slot chrome can... then you reign supreme.

Seems to be a lot of hoohaa about RPMs - sure more is better but free revs ain't what you're racing. I like to dyno under some load... easiest (& most dangerous?) is to spin a propellor, measure with RPM checker.

 

Ok what car are you using?

1, your chassis must be free running as humanly possible. When I ran 540 I loved the TB EvoIII, this is a shaftdrive... only 2 bevel gears in the drivetrain. Gear mesh can be shimmed to fine tune... and the EvoIII can be built so free, one could just blow on the spurgear (no motor/pinion, no wheels) and it'll spin.

If you run belt... sorry. 

2, your suspension & handling must be tuned to allow you to conserve maximum speed through the corners - braking & acceleration is wasteful. You need good racing tyres to keep up corner speeds.

3, Run the slickest body available, minimum wing downforce if you can. Moutn it as low as possible, but make sure it won't scrape the ground. If they allow you to, chop out the rear panel. And the rear window. Heh.

 

Batteries... you want HIGHEST VOLTAGE, nothing else counts.

Old batteries usually go UP in volts, especially Nickel cells. Run old packs with highest volts, long as they have enough juice to finish the race. If you're running lipo then there's less advantage to be had... all you can still do is to top it up to 8.4V for every race.

You'll want a good ESC to pass the juice to motor. Brushed ESCs at high end have zero motor limit and superconductor level of low resistance thru their esoteric FETs. No idea what's good in brushless land, I assume you're racing Blinky.

Hardwire everything. Plugs are for losers...literally.

 

Notice I haven't even talked about the motor yet.  

 

[WillyChang 1814]

Bearings... degrease them fully. Run them dry or a tiny bit of singer sewing machine oil if you really must. Avoid rubber/fibre/Teflon seals, steel only & don't bother replacing them on the inside. 

That's the bearings in the CAR of course, the 540 only has bushings.

 

Motor bushes must be run-in to wear them out. Choose your favourite method & media for accelerated wear. Preferably before the brushes wear out.

 

Comm drops... used to be black art, I accumulated a mass of tiny bottles... in hindsight just made a black mess. (We had some guys even try fashion a "drip feed" comm drops into their motor whilst racing... they didn't necessarily lap everyone.) Don't bother if your motor is cleaned & run-in IMHO. They might help during running in, maybe.

 

Use aerosol "motor spray" to clean your motor, many RC brands sell it. Or buy "electrical contact/switch cleaner" spraycan, nonresidue & plastic safe is best. Whichever is cheaper & stinks less. Works the same.

 

Practice. You need a lot of driving practice. Pick most efficient racing line to keep up corner speeds. Nothing else matters except lap times. And you want to be consistent, no big variance in consecutive lap times. 

 

See? No cheating...  

 

[NobbySideways 113]

Thanks, that's good stuff right there. I've only done one race, but no point giving myself a disadvantage with substandard maintenance. Smoothness will come I guess, the racing lines are coming more naturally now. Strange, it comes a lot more naturally at 1:1 scale!

[Jonathon Gillham 4606]

7 hours ago, WillyChang said:

 unless you can find that famous 1990s vintage 4-slot chrome can... then you reign supreme.

The NZRCA onroad rules specifically exclude the 4 slot Johnson, which I find funny given they haven't been available for 25 odd years, and why would anyone run a silvercan in stock classes when you can run a 21.5T brushless motor.

Interesting thread, I can't add anything, not because its all been said but because I know nothing about it. Sounds fun though.

[markbt73 5316]

7 hours ago, WillyChang said:

Comm drops... used to be black art, I accumulated a mass of tiny bottles... in hindsight just made a black mess. (We had some guys even try fashion a "drip feed" comm drops into their motor whilst racing... they didn't necessarily lap everyone.)

Ah yes, the old Paragon "Turbo Pac"! Banned almost instantly at my local carpet track, because of the mess...

[CoolHands 816]

Probably not crashing is worth 10x a slightly better can

[NobbySideways 113]

10 hours ago, CoolHands said:

Probably not crashing is worth 10x a slightly better can

Not crashing isn't something I can work on from the comfort of home (it's carpet racing). Good upkeep of the car I can at least attempt.

 

I forgot to reply earlier to the question of what car it is, sorry, not Tamiya this time, its a Mardave VRX oe. Our club rules state Mardave G2 motor, but we couldn't get hold of those (nil stock) so they relaxed the rules for generic silvercan. The battery is restricted to NIMH up to 5000mah, 4 cells. 

I only really started doing it as my son races the Schumacher GT12 in a different class and the Mardave Hot Hatches looked like a bit of fun without all the faff of the GT12. Although they do get brushless and lipo in their class!

[WillyChang 1814]

Oh kool! Didn't realise Mardave is still so active today!! Loved their old ministock.

4cell NiMH huh... you better splurge & get the highest voltage 4 cells you can find  get a good charger & time the charge to finish just before the race. Batt must be warm at the start. 

yeah do some black magic on your 540 per that Japanese sensei above

what bodies are you running? Slam it as low as you can. If it's opaque ABS cut out all the windows not paint them in with black. 

I guess gearing is "fixed"... but anything in the rules about tyre diameters? Get the biggest fattest donuts you can glue on.

Plus if you're not going all that fast you probably don't need that huge widths of foam contacting the ground. I'd be looking at spinning them on a tyre truer/lathe/drill and cutting 3-4 wide grooves with a curved file. Anything in t he rules against that?