motors with longer shafts

[Saito2 6673]

My old Kyosho car crusher trucks need their pinions installed with the gear section facing inward, toward the motor can. Thusly, typical Tamiya silvercans can't be used as their motor shafts are too short. Any sealed can motors around the power of a Torque-Tuned (but not much more as a want to preserve these old trucks) out there that would fit the bill?

[guggles 79]

most traxxas motors have a fairly long motor shaft.

[Saito2 6673]

1 hour ago, guggles said:

most traxxas motors have a fairly long motor shaft.

Good suggestion. Perhaps a 21T Emaxx 550 on 7.2v will approximate a 27T 540 on 7.2v but with extra torque. Old Kyosho trucks seem geared rather high. I have a suspicion they might have just transferred the Icarus/Pegasus gearbox over with only a pinion change but I'd have to track down the manuals to be sure. 

[markbt73 5310]

Those Dynamite 20 turn motors from the ECX RTRs have the long output shaft. And they're not too powerful; equivalent to a Sport Tuned in feel. I think RC4WD sells a 27 turn one also, but you'd have to double-check the shaft length.

[Saito2 6673]

On 5/28/2022 at 3:31 PM, Saito2 said:

I have a suspicion they might have just transferred the Icarus/Pegasus gearbox over with only a pinion change but I'd have to track down the manuals to be sure. 

Suspicion incorrect. While it appears some of the gears and half shafts are shared between the two, the Big Brute's gearbox is larger and incorporates an extra idler gear. The truck still feels geared a bit too high for its size/weight.

[Toolmaker72 507]

On 5/28/2022 at 5:26 PM, Saito2 said:

My old Kyosho car crusher trucks need their pinions installed with the gear section facing inward, toward the motor can. Thusly, typical Tamiya silvercans can't be used as their motor shafts are too short. Any sealed can motors around the power of a Torque-Tuned (but not much more as a want to preserve these old trucks) out there that would fit the bill?

Could you drill a new grub screw hole in a position suitable for a motor with a shorter shaft?

[Saito2 6673]

2 hours ago, Toolmaker72 said:

Could you drill a new grub screw hole in a position suitable for a motor with a shorter shaft?

Unfortunately, there's not enough space on the pinion for such an endeavor. Thanks for the suggestion though.

[Toolmaker72 507]

1 hour ago, Saito2 said:

Unfortunately, there's not enough space on the pinion for such an endeavor. Thanks for the suggestion though.

Just out of curiosity, could you show on a picture the pinion on a short shaft motor please?

[Saito2 6673]

 

On 6/11/2022 at 6:12 PM, Toolmaker72 said:

Just out of curiosity, could you show on a picture the pinion on a short shaft motor please?

This is how the pinion typically mounts in the truck, but as you can see, the shaft is too short on this common Tamiya silvercan (the same would be true for the Torque Tuned motor I want to use) and the gear is too close to the motor can. Flipping the gear around, in the more typical Tamiya way, places the gear section too far into the gearbox where it won't mesh with the spur.

ps: please excuse my daughter's assortment of blocks and Peppa Pig house in the background. lol

[SupraChrgd82 1425]

The “ultra lightweight pinion gears” and hybrid pinions used by racers tend to be pretty narrow.  Would those suit your application, Saito2? You’re not the sort to abuse the drivetrain, so the small teeth would be of little consequence…

[Jonathon Gillham 4605]

I've been following this as the Super Astute requires a longer motor shaft too. The Super Stock TZ and RZ both fit but the silvercan etc don't and I would rather a slower motor.

[Saito2 6673]

2 hours ago, Jonathon Gillham said:

I've been following this as the Super Astute requires a longer motor shaft too.

Yes, that's the same problem I'm having. IIRC the Egress is in the same boat. I used the stamped metal Vanquish motor mount in  place of the stock Egress one  to allow me to use a short shaft Torque Tuned motor.

[Toolmaker72 507]

11 hours ago, Saito2 said:

 

This is how the pinion typically mounts in the truck, but as you can see, the shaft is too short on this common Tamiya silvercan (the same would be true for the Torque Tuned motor I want to use) and the gear is too close to the motor can. Flipping the gear around, in the more typical Tamiya way, places the gear section too far into the gearbox where it won't mesh with the spur.

ps: please excuse my daughter's assortment of blocks and Peppa Pig house in the background. lol

I wondered if the gear could be modified with a larger hole say 5mm and then an extension machined to suit the motor shaft using a 5mm diameter shaft. So in effect extension is secured to motor shaft then pinion grub screwed to the extension piece.  Does that make sense?  

[Saito2 6673]

6 hours ago, Toolmaker72 said:

So in effect extension is secured to motor shaft

Is the extension hollow to slip over the existing motor shaft? How would it be secured to the motor shaft? I understand enlarging the pinion hole to fit over the extension shaft.

[Toolmaker72 507]

11 hours ago, Saito2 said:

Is the extension hollow to slip over the existing motor shaft? How would it be secured to the motor shaft? I understand enlarging the pinion hole to fit over the extension shaft.

Yes, make the extension part hollow to fit over the motor shaft and solid where the pinion is screwed to it.  To secure to the motor shaft I would go with a shrink fit by making the hole undersize by 0.1mm, warm up with a blow lamp so it expands to drop onto the motor shaft.  Once cool it will be on for good

[bavee 1032]

I have some 55T/45T/35T motors from RC4WD and the shaft is slightly longer than that of a silvercan (my RC4WD motors have a 11mm shaft). I see they also do 27T/20T ones:

- Engine & Motor (rc4wd.com)

[Saito2 6673]

11 hours ago, bavee said:

I have some 55T/45T/35T motors from RC4WD and the shaft is slightly longer than that of a silvercan (my RC4WD motors have a 11mm shaft). I see they also do 27T/20T ones:

Thanks for the suggestion. I had some of these (the 20T ones) tucked away for another project I forgot about. They did the trick!

[bavee 1032]

Great! Have been reading a lot of the very interesting topics you started on TC. Glad I could help you out a little on this one.

[Champ85 609]

I assume the reason why the pinion is fitted backwards on the shaft is because if it were mounted normally, it would stick out too far and miss the spur gear.  Is it possible to space out the motor from the mounting plate so that the pinion is brought back into full mesh with the spur gear?

[Saito2 6673]

20 hours ago, Champ85 said:

Is it possible to space out the motor from the mounting plate so that the pinion is brought back into full mesh with the spur gear?

In this particular scenario, extending the motor can via a spacer will cause clearance problems with the suspension, but you theory is sound and perfectly applicable to other vehicles I have that face similar issues. Thanks!