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Melvis

Blackfoot overheating and run time issues

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Hi. My first post, so thanks in advance for any help offered! 

I've just bought and built a 2016 Blackfoot. Everything standard apart from metal ball bearings. 3000mah nimh battery.

The transmission seems very smooth and working properly. But with the motor in, if i turn the rear wheels forward (with my hands) it doesn't turn as easy as I think it should. When I turn them in reverse its harder again. So this was concerning. The gear mesh is good.

When running it, to me, the truck seems slow. I expected a quicker pickup. With a 10T pinion the top end is never going to be that quick. The engine gets hot quickly and after 4 or 5 minutes it is extremely hot to the touch. ESC is not hot. After about 5 minutes the car loses any punch it did have and after about 7 minutes its lost a lot of speed. It could run for a few more minutes but the fun has gone by that stage.

Other thing to mention, it doesn't freewheel very far. In reverse, though reverse is slow, it practically doesn't freewheel at all. 

I'm trying to work out how much of this is normal as Ive never had a tamiya truck before, and how much is a problem. I'd be happy to buy a better motor and battery but no point if the same problems persist. My daughter has a Tamiya Racing Fighter, same set up, and it is so much faster, runs so much longer, motor doesnt get hot etc, that I'm left a bit disappointed with Blackfoot. It looks great though!! 

Many thanks for any advice. 

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I don’t think this sounds right, I have the monster beetle which I think is basically the same transmission (wait to be corrected) I did swap out the gears for a ball diff, apart from that, all is stock. The wheels move with equal torque when turned forward and back when held together.

When you spin one wheel does it still feel different forward to rear? Does the opposite wheel spin in the opposite direction correctly?

This does sound like the motor is doing more work, can you strip back and check the gear box for unusual contact?

Also, does the Blackfoot have the same correction paper as the MB? Assuming this part is the same.. I’ll have a scan of the Blackfoot instructions online now...

image.jpg

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If you have the standard kit silver can motor in there, disconnect the motor from the ESC, and with the wheels off the ground put a single 1.5v dry cell across the motor wires and the wheels should turn.

If not, the screws holding in the motor could be too long and fouling the rotor, the motor could be almost burnt out/brushes worn out, or the gear train binding/seized bearing etc.

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31 minutes ago, Melvis said:

Other thing to mention, it doesn't freewheel very far. In reverse, though reverse is slow, it practically doesn't freewheel at all. 

Reverse shouldn’t be slow, so if you’re confident it’s not ESC set up or transmitter related it must be mechanical, you could hit the reverse signal switch on the transmitter and check it now is slow going forward (reverse on the transmitter) to rule out transmitter set up?

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26 minutes ago, Lee76 said:

I don’t think this sounds right, I have the monster beetle which I think is basically the same transmission (wait to be corrected) I did swap out the gears for a ball diff, apart from that, all is stock. The wheels move with equal torque when turned forward and back when held together.

When you spin one wheel does it still feel different forward to rear? Does the opposite wheel spin in the opposite direction correctly?

This does sound like the motor is doing more work, can you strip back and check the gear box for unusual contact?

Also, does the Blackfoot have the same correction paper as the MB? Assuming this part is the same.. I’ll have a scan of the Blackfoot instructions online now...

image.jpg

Thank you. The diff is working fine. And I stripped the transmission the other day and it looks good. I attached the motor (as a test) in a way where you can see the gear mesh and that looks good. Was that you meant by the correction paper ( the bit about the pinion)?

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29 minutes ago, Fuijo said:

If you have the standard kit silver can motor in there, disconnect the motor from the ESC, and with the wheels off the ground put a single 1.5v dry cell across the motor wires and the wheels should turn.

If not, the screws holding in the motor could be too long and fouling the rotor, the motor could be almost burnt out/brushes worn out, or the gear train binding/seized bearing etc.

I've tried this with a new C battery. Is that what you mean? I can hear something very faint. But the wheels do not turn. I can try adding washers or something to shorten the screws in case 'fouling the rotor'. 

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19 minutes ago, Lee76 said:

Reverse shouldn’t be slow, so if you’re confident it’s not ESC set up or transmitter related it must be mechanical, you could hit the reverse signal switch on the transmitter and check it now is slow going forward (reverse on the transmitter) to rule out transmitter set up?

I hit reverse signal and its slow forward and quick reverse, so guess the transmitter set up OK? When setting it up I didn't really do anything. I havent set high point etc. All I did do was minimise the neutral brake

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You could swap the motors between Blackfoot and Racing Fighter, see if it speeds one and slows the other?  Also while the motor is out, make sure that all wheels are spinning freely.

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12 minutes ago, Melvis said:

Was that you meant by the correction paper ( the bit about the pinion)?

Yes, the stand off, the Blackfoot instruction has 22mm online.. which is different again...

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15 minutes ago, Melvis said:

I've tried this with a new C battery. Is that what you mean?

I mean the AA batteries you likely have in your transmitter. It needs to be good, at least 1.45v, but it should definitely turn the wheels with a silver can motor.

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6 minutes ago, Melvis said:

I hit reverse signal and its slow forward and quick reverse, so guess the transmitter set up OK? When setting it up I didn't really do anything. I havent set high point etc. All I did do was minimise the neutral brake

So it’s either a mechanical issue in your gear box or an issue with the motor, I’m afraid I’ve no experience with failed or failing motors.. If you’re confident all the gear box is correct then must be the motor itself. Can you check the length of the mounting screws? BB1 3 x 30 in the manual? Perhaps put some pics up of the motor off the car and the gearbox just in case.. apart from these suggestions I think I’m out of ideas.. The big guns normally come in soon to these discussions.. fingers crossed for you.

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4 minutes ago, tamiya3speed said:

You could swap the motors between Blackfoot and Racing Fighter, see if it speeds one and slows the other?  Also while the motor is out, make sure that all wheels are spinning freely.

I was just thinking this. I can't see all the numbers because of the tamiya sticker, but the BF has their standard motor. But actually the Racing Fighter came with a 'torque tuned motor. So I can't try that but it looks like it is the faster motor. The question will be whether it heats up as bad. 

When I turn the motors out of the car, the BF standard motor doesn't turn that freely. The Racing Fighter motor turns completely freely. Think I need to give the BF a run with that motor... BTW, when the motor is out of the BF the wheels turn freely. So it looks like the motor...

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Just now, Fuijo said:

I mean the AA batteries you likely have in your transmitter. It needs to be good, at least 1.45v, but it should definitely turn the wheels with a silver can motor.

Ive not tried this myself.. I’ll do this on the MB and feed back my findings :)

 

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I wonder if the motor is faulty what is the com like is it all black and dose it spark lots when its in use you should be able to see this through the two small holes in the case of the motor. also are all of the bearings fully pressed in and the drive shafts have end float as if these don't have end float it might be doing something weird and jamming something.

Welcome to the club and I really like the black foot they are fast I had a vintage one and it was quite slow and I were a bit disappointed and it turned out to be a dodgey motor don't give up on it, it will be worth it in the end everything is fixable

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Can confirm the battery turns the motor (on car) both directions same speed.

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59 minutes ago, Fuijo said:

If you have the standard kit silver can motor in there, disconnect the motor from the ESC, and with the wheels off the ground put a single 1.5v dry cell across the motor wires and the wheels should turn.

If not, the screws holding in the motor could be too long and fouling the rotor, the motor could be almost burnt out/brushes worn out, or the gear train binding/seized bearing etc.

Checked the length of the screws and they do not extend into the motor. They only go into the motor bracket. 

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10 minutes ago, Melvis said:

When I turn the motors out of the car, the BF standard motor doesn't turn that freely. The Racing Fighter motor turns completely freely. Think I need to give the BF a run with that motor..

Sounds to me like the motor has outlived its usefulness and it's time for the big round retirement home.

One thing to check first, make sure the magnets haven't attracted an object like a screw or washer that's jammed in there.

 

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4 minutes ago, Lee76 said:

Can confirm the battery turns the motor (on car) both directions same speed.

I've installed the torque tuned motor. It feels nice and free, forward and back. I tested it with a C battery and it now turns forward and back, same speed. So it looks like its a dodgy motor! I have a full battery so will rest it now.

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Hopefully a stock saver can shouldn’t cost too much on ebay, given all the people inclined to upgrade!

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This thread is useless without pics!   I want to see the motor.  I want to see if there is anything inside the can, like rocks, dirt, a washer/screw/nut.

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Just now, Champ85 said:

This thread is useless with pics!   I want to see the motor.  I want to see if there is anything inside the can, like rocks, dirt, a washer/screw/nut.

Are you demanding a full autopsy? X-ray examination followed by resin potting and sectioning in 5mm slices, some acid etching and a bosh them under the scope. I’m in..

Joking aside, I am intrigued as to how often new motors are found to be faulty with no builder error, and if it has picked up some magnetic debris I want to see this too :)

 

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Hi all. Just been outside for 8 minutes. The truck is rapid and is great fun in the wet. So it was the motor. I feel I shld have just swapped them before I posted, but didn't think. Thank you for all your help and comments. 

So I will get back to the shop about the motor. Its brand new. I dont see any debris in there, all looks clean. So just a faulty motor?

Some other questions if I may? Am I OK to run the tamiya sport tuned motor from the Racing Fighter? I've read about the transmission case bulging - do I need to be pro active here? Or should I return to the standard tamiya motor?

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1 minute ago, Lee76 said:

Are you demanding a full autopsy? X-ray examination followed by resin potting and sectioning in 5mm slices, some acid etching and a bosh them under the scope. I’m in..

Joking aside, I am intrigued as to how often new motors are found to be faulty with no builder error, and if it has picked up some magnetic debris I want to see this too :)

 

the windows into the motor are not big. I can't see anything amiss and I can't take it apart right? 

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3 minutes ago, Melvis said:

the windows into the motor are not big. I can't see anything amiss and I can't take it apart right? 

In my experience.. everything comes apart, it just doesn’t necessarily go back together :)

  I’m not sure what kind of comeback you have with the supplier, if its even worth your time. They sell for about £5 on ebay.

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