Pulled out the 10's

Nasphere · Post by **Nasphere** » Wed May 03, 2006 10:49 pm

Well I decided to go through all the 10 scale shit i've had laying around for a few years.

Whipped out this 4wd Tamiya Thunder Shot..

Decided the motor is a piece of crap so I tossed it. I dug up this old box of motors my friend gave me a long time ago. Started tearing some of em apart to clean em and came accross this Reedy Mod motor. WOW is this thing nice

It has ball bearings, double band slotted brushes, adjustable timing, 20 turn double core.

Then I pulled out the old box of electronics and picked these out:
Futaba high torque, ball bearing servo. (overkill for these little tires lol)
Futaba 2 channel BEC reciever.
Futaba "MC112B" Full FET ESC with 2 second reverse delay.
I also discovered I had a brand new AMP MAX II 1500mAh pack.

I discharged, and peaked the pack, hardwired the motor in with some hefty wires, replaced the battery plugs with really good Dean's power connectors on the ESC and battery.

I took it outside for a little bashing.. And this thing's just shitty for some reason.. lol. I don't think it's the gearing, maybe just friction in the driveline? The motor gets really hot really fast and it seems not to have much power. I used to change timing on the motors a lot a while back, so I tuned this one in.. Still got hot really fast. So I guess the next step is replace all the bushings with BBs. Gear spacing is just right, the pinion is the one off the original motor.. Maybe 20T double is too much? I had a Trinity Paradox 27T single in there, but that thing killed the batteries in less than 10 minutes

Anyone got any ideas you want to add to what could be wrong?

sg219 · Post by **sg219** » Wed May 03, 2006 11:43 pm

The comm and/or brushes might need cleaned up a bit?

The gauge of wire used is too small? From the motor to the ESC.

Some gunk in the motor? Bearings, bushings, endbell.

Slight short somewhere? Any exposed wires vibrating or moving around while the car is moving and touching something?

Would moisture cause overheating? You said the motor sat for a long while. Maybe there was some moisture in the windings that needed burned off?

Have a second set of eyes look at it if you can. I know that I have missed things and sat there and wondered what the hell was wrong, then stop over Bird's (another BP member) house and him point it out in a second or two. Sometime you just overlook something simple or that you wouldn't norally notice because you look at it all the time.

1/10th scale motors do get pretty hot, so it also could be normal.

BTW, For those of you that remember, Bird should be back online in a week or so. Optimisticly.

Nasphere · Post by **Nasphere** » Thu May 04, 2006 12:40 am

The motor is unmarked so all those findings are from rebuilding it. It does seem to be the best motor i've ever run in it.. It's an old school competition Reedy modified motor, so I doubt it's lacking anything lol. I mean who balances their armatures for backyard bashing?

I think it's mostly friction in the driveline. It's an old Tamiya 4wd buggy full of teflon bushings. And plastic this old shrinks, so maybe it just needs to be run in a bit. Either way, I'm gonna have a rebuild session tomorrow and toss full ball bearings into it. Hopefully that'll cure the heat/slowness/short run times.

Unfortunatly i'm the only "smart" person in the area that knows RC, so 2nd eyes are hard to come by.

And thanks, i'll clean up the comms and brushes a bit. I did notice some pitting from dirt or whatever..

betty.k · Post by **betty.k** » Thu May 04, 2006 1:13 am

toolbox in a can

crazydave · Post by **crazydave** » Thu May 04, 2006 7:04 am

This might be an obvious question, but it needs to be asked. Did you change the gearing? You can not run the same gearing with a mod motor as you did with the stock motor. Mod motors give up torque in exchange for speed. You should probably come down a couple teeth on the pinion.

So I guess the next step is replace all the bushings with BBs.

Never run a mod motor with bushings, you risk not only burning up your comm and brushes, but ESC also.

Nasphere · Post by **Nasphere** » Thu May 04, 2006 7:24 pm

crazydave wrote:This might be an obvious question, but it needs to be asked. Did you change the gearing? You can not run the same gearing with a mod motor as you did with the stock motor. Mod motors give up torque in exchange for speed. You should probably come down a couple teeth on the pinion.

lol, ok, that works.. I didn't think of that (i did but it didn't click)! Nice idea. It's a 15 tooth, so I think I could come down to a 13 er so.

crazydave wrote:
nasphere wrote:So I guess the next step is replace all the bushings with BBs.
Never run a mod motor with bushings, you risk not only burning up your comm and brushes, but ESC also.

Yeah. lol, the ESC did get a bit hot.. Anyways I disassembled most of the front and rear gearboxes and found mostly bearings, the bushings that were there were on the output shafts, which i changed to bearings last night.

Another thing I found, that explains the binding of the rear wheels, they had tiny O-rings inside the coupler thing for the CV axle to keep the axle from moving around. apparently the rubber was just putting too much force on the axle, causing the friction between the output yoke and bushings (which are now bearings). It seems to roll pretty damn good now without a motor!

TY dave, SG, and betty!

I'm just waiting on a pack right now to try it out!

EDIT: (fixed quotes)

crazydave · Post by **crazydave** » Thu May 04, 2006 8:58 pm

Actually 20-turns aint too hot. 14-tooth pinion should be good.

I'm guessing from the small number of teeth and its a old Tamiya that its got 32 pitch gears? If so one tooth would make a more drastic difference anyways.

Nasphere · Post by **Nasphere** » Thu May 04, 2006 10:43 pm

crazydave wrote:I'm guessing from the small number of teeth and its a old Tamiya that its got 32 pitch gears? If so one tooth would make a more drastic difference anyways.

Yeah, 32.. That brings me to a small problem. All the 32 pitch pinions I have are 15 tooth aluminum, and almost all of em are warn in a bit... I have a ton of the 48 pitch pinions cause that's what I used with my losi. So, meh.. A stock motor in the ThunderShot I guess is the choice.

I guess i'll just rebuild my Losi Junior-T tranny and toss bearings in there, along with that Reedy motor. I'm trying to fix my 'Novak Explorer Sport II' ESC. It doesn't seem to be getting a signal.

RC cars that've been sitting for this long have 1 problem in common. All the damn shocks need rebuild kits!

I remember that Losi truck used to kick the crap out of all the neighbor's cars n trucks.. Including my brother's Losi Junior Two buggy!

Nasphere · Post by **Nasphere** » Fri May 05, 2006 4:54 am

I decided for simplicity's sake, I'd just toss electronics into the Losi..

I love the results!

It's just the batteries are old as hell.. It lasts about 3 minutes... Guess I need a new pack er two.

crazydave · Post by **crazydave** » Fri May 05, 2006 7:05 am

Nasphere wrote:I decided for simplicity's sake, I'd just toss electronics into the Losi.. I love the results!

It's just the batteries are old as hell.. It lasts about 3 minutes... Guess I need a new pack er two.

You know, those old batteries only lasted about 4-5 minutes when they were new. Definately get some updated batteries.

I'm jealous you got all these old 1/10th scales to play with. I really should of hung on to mine.

payaso · Post by **payaso** » Fri May 05, 2006 4:44 pm

crazydave wrote:I'm jealous you got all these old 1/10th scales to play with. I really should of hung on to mine.

Cabo has an OG Kyosho turbo Optima 4WD that's just sitting there. I been trying to get him to revive it for some time. That would be awesome.

silla

crazydave · Post by **crazydave** » Fri May 05, 2006 5:10 pm

payaso wrote:
crazydave wrote:I'm jealous you got all these old 1/10th scales to play with. I really should of hung on to mine.

Cabo has an OG Kyosho turbo Optima 4WD that's just sitting there. I been trying to get him to revive it for some time. That would be awesome.

silla

I know, he's got that gold tub RC10 too. He really does need to break that stuff out.

Post by **CaboWabo** » Fri May 05, 2006 5:42 pm

The RC10 will probably be easier to get running.
The Optima is totally gutted and I don't think I have the shit to slap in it.
It would be cool to get them running again though.

Nasphere · Post by **Nasphere** » Fri May 05, 2006 6:08 pm

crazydave wrote:I know, he's got that gold tub RC10 too. He really does need to break that stuff out.

Lol, I have two of thos old guys sitting in the garage

Deep ass tub, gold anodized RC10's.. One's missing the spur mounted diff though.. But as cabo said, one of those wouldn't be hard at all to get going again.