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Silver Can Motor Tips/Tricks

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Old 09-06-2010, 08:34 PM
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So in general is the old manual balanced 4 hole motors better then the newer machined balanced motors?? I hear allot of ppl say these motors are only good for mini and not TC as they don't have the torque the new ones do.

My G/F runs a 4 hole motor which is so old its not funny.. pulled it from a car which was in the garage for 15 years. Where the pinion goes it has even turned blue.. but the motor is still very fast.. geared it to rev and the motor performs better on the dyno then any of my newer motors. But the motor keeps spining for 10 seconds after I turn the dyno off (magnets must be very weak)...

Cheers


Originally Posted by rccardr View Post
Sorry, Ben, I was out of town and missed your previous question. The Johnson motors are better built, beter balanced, and use higher quality components, hence the significantly improved performance. We've messed around with the Mabuchi motors with some success, but as soon as we get them going faster they burn up. It seems that armature balance is critical to ultimate performance. One reason the old 4-slot motors were generally faster than their two-hole counterparts was that we believe the arms were manually balanced. By the time the two-holers arrived they had moved to machine balancing.
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Old 09-07-2010, 09:53 AM
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Thanks for the reply rccardr,

I appreciate the insite. Luckily, so far the cleaned Mabuchi's seem to be good enough. They will likely need more maintaniece than the Johnsons it sounds like. Just for clarification. Are the 2-hole vs. 4-hole motors you are describing made by Johnson or Mabuchi? Also, is this reference to the holes on the end bell or the pinion side?

Thanks again,

Ben
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Old 09-07-2010, 09:57 AM
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The 4-hole motors were made by Johnson. The # of holes refers to the holes in the can (a new #53689 is a two hole motor). They all require pretty mich the same amont of maintenance (from zero to constant, depending on your preference ).

Bottom line is the 4 hole motors were more consistently fast than the 2 holes are today, although the modern motors have better magnets and should last longer.
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Old 09-07-2010, 11:18 AM
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I had a 4-hole do that, and it became the best damn motor I've ever had.

To keep it from sliding around I put a motor bearing on the shaft, and it had enough pressure on the shaft to keep it from sliding. Keeps things from binding as well if it's hit, as it'll just spin on the shaft.

Perfect for running Mini if you forgot to bring your pinion guide, it's just 1mm short of where the pinion goes

Originally Posted by rccardr View Post
Silver cans do that when you slap the wall with the left side of the car. In an F1 it can take a remarkably slight impact to completely mess up the armature, due to the way the motor mounts in the rear pod.

What happens is that the phenolic resin washer at the top of the comm will either shatter or compress, and/or the driveshaft itself will migrate up the stack.

Best way to keep this from happening (except for avoiding the lefty slap) is to place a small spacer (or a stack of motor washers) on the driveshaft between the pinion and the motor snout. Leave just enough room for the pinion/shaft to rotate freely. If you hit the wall you might move the magnets (in itself not necessarily a bad thing) but the shaft will remain in place relative to the rest of the motor.

Keep motor temp under 180 and you will be fine.
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Old 09-11-2010, 07:59 PM
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I've been doing some more tinkering with these motors and was wondering if more amps drawn at a set voltage was better than less. And what sort of current draw I should be looking for.

Thanks
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Old 09-12-2010, 08:54 PM
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Originally Posted by Mitch-e4fs View Post
I've been doing some more tinkering with these motors and was wondering if more amps drawn at a set voltage was better than less. And what sort of current draw I should be looking for.

Thanks
It is a double edge sword.

More amp draw can indicate drag or binding in the motor.

Too much amp draw can cause the motor to over heat.

From a power stand point more amps can be better, too much amps will generate heat causing the motor to run flat or grenade during a race.
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Old 09-13-2010, 08:22 AM
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Originally Posted by A-Ko View Post
It is a double edge sword.

More amp draw can indicate drag or binding in the motor.

Too much amp draw can cause the motor to over heat.

From a power stand point more amps can be better, too much amps will generate heat causing the motor to run flat or grenade during a race.
I've never thought that amp draw was a reliable measure of how the motor would perform. In many cases, high amp draw is a detriment as you've pointed out.

By the way it was good to meet you at the Nats. Glad you could make it.
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Old 09-13-2010, 09:15 PM
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Originally Posted by Granpa View Post
I've never thought that amp draw was a reliable measure of how the motor would perform. In many cases, high amp draw is a detriment as you've pointed out.

By the way it was good to meet you at the Nats. Glad you could make it.
Hi Grandpa,

It was great meeting you, The Legend at the Nats. I keep wondering how well it is to drive your mini. Mine is pretty good, finally built usable sets of tires for it and it woke up. Who knows maybe next time I get out there you might need a driver to do a few laps for you to see how well it is working without focusing on your driving. It also would give me an idea of what a well handling mini is like. I did that letting a friend drive my GT3 car as well as drove a friends F1. The F1 started feeling good, drove it hard and it stepped out, I was done... lol.

I look at RPM and Amp draw and test on a load vs no load dyno. Usually the load gives me a very good indicator. Although the post from Mitch seemed to be looking at Amp draw only, which is like RC driving with one hand. Maybe he does not have a dyno.
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Old 09-13-2010, 09:41 PM
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Unfortunatley i dont have a dyno so all i can work from is current draw.
The motor im working on was pulling 1.8A at 7.2 v with well seated brushes and oiled bushings.

Any thoughts?
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Old 09-14-2010, 12:34 AM
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I thought more amps indicate better torque.. I only have a much more motor master.. and the motors that pull higher amps with similar rpm to other motors seem to pull harder.. might be my imagination.. thats how I gauge which motor to use.. providing there is nothing binding it up and the motor is nice and clean.

If amps is not the way to tell then I better re think what I have been doing..

Say you have two motors both run in which are running 18500rpm at 7.2volts.. one is pulling 2.2 amps and the other is only pulling 1.3 amps.. which motor would you race if you didnt have a dyno that measured power?

Cheers
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Old 09-14-2010, 08:57 AM
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Originally Posted by warnos View Post
I thought more amps indicate better torque.. I only have a much more motor master.. and the motors that pull higher amps with similar rpm to other motors seem to pull harder.. might be my imagination.. thats how I gauge which motor to use.. providing there is nothing binding it up and the motor is nice and clean.

If amps is not the way to tell then I better re think what I have been doing..

Say you have two motors both run in which are running 18500rpm at 7.2volts.. one is pulling 2.2 amps and the other is only pulling 1.3 amps.. which motor would you race if you didnt have a dyno that measured power?

Cheers
Like all hypothetical questions, the one you set up, was done to give a certain answer. You wouldn't have that wide a variation in amp draw and motor #2 drawing 1.3 amps is what you'll see in a decent stock motor. Motor #1 has something dragging, but could be a "great" by working on the bushings or running in a bit longer to get the amp draw down. Also, if the amp draw readings were "flash" readings those are not reliable. You'll find that if the motor is run for, say 20-30 seconds, the amp draw will be lower and will have settled down.

So after all that, I'd pick motor #1. Besides, driver feel is probably the most inaccurate way of judging motor performance in existence. Lap times are the only reliable way to track test a motor. You have to have a 500 rpm difference in motors before you see much of a difference on the track.

I use a MuchMore tester for stock motors as I haven't found that using my Fantom dyno is worth the effort for box stock motors. At least you're not using the Integy which can give good readings, but is damn near impossible to use consistantly.
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Old 09-14-2010, 09:35 AM
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Originally Posted by A-Ko View Post
Hi Grandpa,

It was great meeting you, The Legend at the Nats. I keep wondering how well it is to drive your mini. Mine is pretty good, finally built usable sets of tires for it and it woke up. Who knows maybe next time I get out there you might need a driver to do a few laps for you to see how well it is working without focusing on your driving. It also would give me an idea of what a well handling mini is like. I did that letting a friend drive my GT3 car as well as drove a friends F1. The F1 started feeling good, drove it hard and it stepped out, I was done... lol.

I look at RPM and Amp draw and test on a load vs no load dyno. Usually the load gives me a very good indicator. Although the post from Mitch seemed to be looking at Amp draw only, which is like RC driving with one hand. Maybe he does not have a dyno.
My LWB Mini is pretty good and suits my driving to a T. Too bad that a good driver didn't have it cause there is easily .5 seconds and as much as 1 sec in there over my driving. It was in cruise mode all weekend cause I'm not good enough to consistently drive the tight lines. Had Brandon K and Micheal Monaghan test it and Bk thought it was "really good" and MM told me "it's perfect. Don't change anything". Any time you come out, you're welcome to drive anything I've got. Also have a GT3 TA05 that's very good and have joined the FF03 craze and hope to get that working.

We're pretty much in sync on the motor testing, but I rarely test a stock motor on the Fantom any more. Will have to tho cause the last 540s that we got at the Nats were a little different. Haven't had time to take a close look, but will have to break out the magnifiers and dyno and do a little checking. Altho, I have a feeling Doc's miles ahead as usual.
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Old 09-14-2010, 11:13 AM
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not to get off topic but what are most guys running for esc? Our local hobby shop is getting a silver can class going on there small carpet track. How important is a good esc when using these motors? Thanks -Jeremy
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Old 09-14-2010, 04:32 PM
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Originally Posted by dirty petcock View Post
not to get off topic but what are most guys running for esc? Our local hobby shop is getting a silver can class going on there small carpet track. How important is a good esc when using these motors? Thanks -Jeremy
I have found that it does make a difference.

I ran a 540 Johnson with a Novak XTB ESC, then switched to an LRP SPX and found I was quicker and smoother on the track.

I guess the newer the ESC the better its brushed profile will be....maybe .

Ben
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Old 09-14-2010, 08:07 PM
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Originally Posted by Granpa View Post
Like all hypothetical questions, the one you set up, was done to give a certain answer. You wouldn't have that wide a variation in amp draw and motor #2 drawing 1.3 amps is what you'll see in a decent stock motor. Motor #1 has something dragging, but could be a "great" by working on the bushings or running in a bit longer to get the amp draw down. Also, if the amp draw readings were "flash" readings those are not reliable. You'll find that if the motor is run for, say 20-30 seconds, the amp draw will be lower and will have settled down.

So after all that, I'd pick motor #1. Besides, driver feel is probably the most inaccurate way of judging motor performance in existence. Lap times are the only reliable way to track test a motor. You have to have a 500 rpm difference in motors before you see much of a difference on the track.

I use a MuchMore tester for stock motors as I haven't found that using my Fantom dyno is worth the effort for box stock motors. At least you're not using the Integy which can give good readings, but is damn near impossible to use consistantly.

Ok thanks Granpa.. I have been mainly using my motors with hi amps thinking they were better (using them in TC not mini).. I will give the motors with a lower amp reading a go... there are a heap of them in my draw as I thought they were not as good as my motors with higher amp readings.

One thing I notice with the motors that have a higher amp reading is they drop off allot faster then the motors with a lower amp pull.. but they do seem faster for the 1st half of the race..

Question when you run in your motors is that what you aim for.. a lower amp draw? I am a bit of a novice with 540's.. but if the motor is clean would stronger magnets mean higher amps? Or can't you tell if a motor has good magnets this way?

My 4 hole motor which has allot of top end not much torque and has an amp reading of 1.2 @ 7.2.. thats kinda why I thought hi amp more torque.

Thanks..
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