TOPIC:

Hello people. I installed the brand new rz motor with a 15 pinion. Test running the car slowly with wheels off the ground everything heats up a lot. Resistors, engine, engine wires to speed controller and thus the sc. definitely not normal, especially for just a few suspended minutes. Voltage is correct. Maybe the sc can’t handle the amps?
Any ideas?
Thanks!

Hi, do you need a heat sink on the motor ?

If you use the msc, it doesn't support the power of the motor. Put a modern esc .

Thanks Al but it’s not a problem of the motor, heat sink can help but slightly. As I thought it’s the msc that can’t hold motor amp or power.

Thanks stingray-63. I’m sure as I suspected it is the msc that can’t deal with the engine. I’ll try it today on the track for small runs at a time and see what happens. The thing is I don’t want an esc in the car. Want to keep it powerful but vintage. I think the rz will have to go. Still searching for a decent priced technigold motor...

Girox wrote:

Hello people. I installed the brand new rz motor with a 15 pinion. Test running the car slowly with wheels off the ground everything heats up a lot. Resistors, engine, engine wires to speed controller and thus the sc. definitely not normal, especially for just a few suspended minutes. Voltage is correct. Maybe the sc can’t handle the amps?
Any ideas?
Thanks!

Lots to try - first, how hot is hot? Don't try touching the resistors as they will burn your fingerprints off, but anything up to 70 Celcius is safe IMO. That's about 3 seconds contact before it feels too hot ...

Next, is the pinion binding? With a 15T pinion, you need 2 of the set plates either side of the lower 27mm mount screws. You could also have the pinion too far along the motor shaft & the end rubbing on something in the gearbox. Another possibility is that the motor has 4 3mm mount holes, are you defininately using a diametrically opposite pair? You can test the motor and binding with a single 1.5v alkaline "D" cell. It will turn the motor and transmission slowly, but it should turn, and smoothly.

Using an MSC equipped car on the bench is a bad idea, especially at the lower 2 speeds. There is no airflow so cooling is compromised, plus you have to think how the MSC works - it reduces motor speed by burning off the excess current as heat. nb, This doesn't work that well even when the car is moving, I've bought used cars where components have melted (Schumacher chassis, Wild Willy hood, Willy's Wheeler windscreen) and many, many more where the insulation on the wiring has melted due to conducted heat, and fused.

I don't think that a 23T motor is necessarily too much for an old MSC, assuming nothing is binding, there isn't too much drag from the surface your're running on, and you keep the speed up - but it is very much at the upper limit. I ran a Wild Willy 2 with a 19T motor on the stock MSC & wiring, but the contacts on the MSC did turn blue like motorbite exhaust pipes ...

The pinion isn’t binding anywhere I’ve checked that measuring with a caliber. Also two plates up and two down, done that correctly as well.
The motors 4 3mm holes are centered diagonally I hope so, because it’s very hard to see down there even with markings. However the engine runs smoothly connecting a D battery. The wires inside the servo room, steering servo and arm seemed good before when I opened it up recently. I’ll check again after trying to run the car.

Thanks a lot Jonny retro

Good day people. First of all I wanted to thank you for your insight, it was helpful and got some troubleshooting done. Also, since I’m new in the forum, thanks for always responding.
Temperatures are normal running the RZ 23t motor in the 58054 Supershot to the point that I fitted a 17t pinion now and it rips! (@jonny retro, you were dead in that it was a bad idea running the car even for a few short minutes on the bench!) overheats like crazy while temps are more then normal while running. Didn’t think it could have made such a difference!
Anyhow the Supershot/RZ/17t pionion work well. The only thing is I have no low end. It’s just on/off. Nothing or full power almost. Not really perfection I’d say. Also I can really hear the slip diffs agonizing as I pull out of corners or accelerating in a straight line from standstill. I try and not use a heavy finger but it’s almost impossible.
Other than the Supershot I’m working on my 58045 hornet. Running slick tyres in the rear and the a technipower for power. Just opened it, cleaned the commutator and lubricated the bearings, and the brushes were in great shape.
Fire in the hole! Will post pictures soon!