Kraton Kraton 6S - 4985SL 1650Kv - Major Heat Problems

[Wraith405]

Hey guys,

Just got done with the first 15 minute full throttle run of my Kraton 6S with the Hobbywing Max 6 and 4985SL motor. I don't currently have a heatsink or fan on, but the ambient temp is around 55 F with a nice breeze. The surface was dirt, short dead winter grass, and concrete.

When I got done, I checked the motor and got 176 F degrees. That seems really high to me for this big of a motor and that short of a run. The ESC wasn't anywhere near that, sitting at around 110 F, but the capacitors were pretty hot. Now, I am running a fairly low end gearing and setup for the Kraton and I don't think I should be having these type of problems. I'm running 6S with the 16 Tooth pinion and stock spur gear. Diff oils are at 30k front and back and 300k Center. All the wheel and diff bearings are new, and it rolls really easy and smooth without the motor in it. I'm running the larger dBoots Backflips tires from the Outcast 6S.

The truck is maybe a hair faster than stock, though it certainly much more torque. There does seem be quite a bit of rolling resistance with the motor installed, but as far as I can tell the drag brake is off. I figured it was just the larger magnets in the motor not wanting to spin.

ESC Settings are normal:

Punch is set at 3
Drag Brake is off
Timing is at 0%

Do I really have to have a heatsink with just the 16 Tooth pinion? Could I have bad motor bearings maybe? Should I contact Hobbywing support?

 

[Jimbobjr]

If you’re running flat out that is about right after fifteen minutes. I run the same setup on 6s and a 20t pinion but have two hobbystar fans on a custom mount to cool things down. My esc overheats now before the motor.

 

[Yas]

You could try a taller pinion. This may seem contradictory, but this large can motor will handle 20t+ without cogging. I'm guessing during the run, your throttle was maxing out quite a lot?

I've also just started to use the Traxxas 3362 heatsink with mine also it needed to be filed to make way for the roll hoop pin

 

[Wraith405]

You could try a taller pinion. This may seem contradictory, but this large can motor will handle 20t+ without cogging. I'm guessing during the run, your throttle was maxing out quite a lot?

I've also just started to use the Traxxas 3362 heatsink with mine also it needed to be filed to make way for the roll hoop pin

Really? That does seem contradictory. I don't think I was maxing out the throttle too much. I mean, the ESC was just fairly warm, around 110 or so. Only the motor was that hot. I was honestly kinda confused about how people could be running 18T or 20T pinions on this motor, given how hot it got with the 16T.

I can definitely try out the larger pinion. I think I have an 18T around here somewhere. I also found that 3362 heatsink so I'll pickup one of those and mount a couple of fans and we'll see if that helps.

Kinda frustrating honestly though. I was hoping with a 16T pinion I could just drive and not worry about temps or anything. That's mostly my goal.

 

[MFM]

I was running 24/46 gearing in my Mojave balls deep in 6s and never getting above 125 even during summer! U need to get urself a nice heat sink/fan set up and not worry bout it ever. At least that’s what I did... I don’t want to worry bout internal bearings or capacitor heating up and shutting down. You have already invested in the big block power, now set urself up w proper cooling and bash away! I was running castle creations WP2.0 programmable BEC set to 10v for the motor fans and running esc fan directly off esc power. Never got above 125ish.

This power set up is now in my stretched talion Minos the NTF fans and external BEC and still stays cool w just heat sink

 

[slick2500]

Really? That does seem contradictory. I don't think I was maxing out the throttle too much. I mean, the ESC was just fairly warm, around 110 or so. Only the motor was that hot. I was honestly kinda confused about how people could be running 18T or 20T pinions on this motor, given how hot it got with the 16T.

I can definitely try out the larger pinion. I think I have an 18T around here somewhere. I also found that 3362 heatsink so I'll pickup one of those and mount a couple of fans and we'll see if that helps.

Kinda frustrating honestly though. I was hoping with a 16T pinion I could just drive and not worry about temps or anything. That's mostly my goal.

As a general rule of thumb.
Cool esc and hot motor = undergeared.
Both hot = overgeared.

 

[Wraith405]

As a general rule of thumb.
Cool esc and hot motor = undergeared.
Both hot = overgeared.

I see. So undergeared means it's basically revving too much then. Too much RPM during standard running? Kinda makes sense. I'll swap to the 18T pinion and see how that goes.

 

[Lukas412]

I say get a fan and heatsink setup and run a 22 tooth pinion. It will be VERY fast.

 

[slick2500]

I see. So undergeared means it's basically revving too much then. Too much RPM during standard running? Kinda makes sense. I'll swap to the 18T pinion and see how that goes.

Yeah the motor is spending too much time in the higher Rpm range sort of like trying to drive down the highway in 4 low.

 

[Yas]

I was running 24/46 gearing in my Mojave balls deep in 6s and never getting above 125 even during summer! U need to get urself a nice heat sink/fan set up and not worry bout it ever. At least that’s what I did... I don’t want to worry bout internal bearings or capacitor heating up and shutting down. You have already invested in the big block power, now set urself up w proper cooling and bash away! I was running castle creations WP2.0 programmable BEC set to 10v for the motor fans and running esc fan directly off esc power. Never got above 125ish.

View attachment 111977

View attachment 111978

View attachment 111979
This power set up is now in my stretched talion Minos the NTF fans and external BEC and still stays cool w just heat sink

Those are some stunning kits ?? spare no expense and get it how you like it ? you fellas in the states always get the best stuff ?

 

[Wraith405]

Thanks for all the help guys!

I've ordered an Xmaxx 3362 heatsink and a 1mm thermal pad, We'll see if I can't shoehorn that thing on there and then cut some of those fins down on the top. Otherwise I don't think the roll cage will fit. I might just take it off, I'm a really conservative driver so there might not be a need for it.

I've already got some fans but if those don't fit I'll try to pick up some of those square fans that @MFM has on his setup.

 

[Wraith405]

Found something interesting when I pulled off the 16 Tooth pinion gear. The teeth are like worn and melted after like 30 total minutes of running. Something's gotta be funky with my setup. I've never seen a pinion gear have wear/damage like this.

 

[Yas]

Found something interesting when I pulled off the 16 Tooth pinion gear. The teeth are like worn and melted after like 30 total minutes of running. Something's gotta be funky with my setup. I've never seen a pinion gear have wear/damage like this.

View attachment 112082

Tight mesh and/or using a new pinion with a worn spur gear causes this

 

[Surchaufeur]

If you cant cooldown your motor enough buy 200$ on fans I don't get it. If a high powered fan from yeah racing or two cant make my motor cool enough Well the setup just doesn't work. Try a higher pinion and see how it goes but monitor the motor temps.

Found something interesting when I pulled off the 16 Tooth pinion gear. The teeth are like worn and melted after like 30 total minutes of running. Something's gotta be funky with my setup. I've never seen a pinion gear have wear/damage like this.

View attachment 112082

Its poop metal what brand this pinion is from?

 

[MFM]

Looks like could have some drag. Check settings. Confirm she rolls freely w out pinion in. I did this to a pinion but I had a spool w bad mesh. Also had worn diff that was rubbing inside or mount. Things shifted after a bad wreck.
make sure she rolls free. Try different pinion. Assure mesh is perfect. Depending on ur mount use a paper towel to gap.

 

[powerarrma]

1: Smooth fresh bearings
2: New fresh diff oils
3: Make perfekt Gear Mesh
4: Have good Lipos
5: Buy dust cover
6: Drive and enjoy only after this
7: Use extra fan if the weather is very hot .

Extra:
don't Use too heavy aftermarket wheels.
Pinion must be right too

Enjoy

PS:
Dust cover is a must to avoit alot problems also.

1-2-3-4 is most important anyways

 

[Stokez]

Found something interesting when I pulled off the 16 Tooth pinion gear. The teeth are like worn and melted after like 30 total minutes of running. Something's gotta be funky with my setup. I've never seen a pinion gear have wear/damage like this.

View attachment 112082

Looks like too tight a mesh. Could help explain why it overheated so easy

 

[Wraith405]

If you cant cooldown your motor enough buy 200$ on fans I don't get it. If a high powered fan from yeah racing or two cant make my motor cool enough Well the setup just doesn't work. Try a higher pinion and see how it goes but monitor the motor temps.

Its poop metal what brand this pinion is from?

No idea what brand it is. It's the original speed pinion from one of my other Arrma's, I don't remember which one.

I think my mesh might have been a bit too loose or too tight for sure. I'll reset the mesh again on the 18T just to make absolutely sure and try that out once more. It's raining here today though so no testing.

Looks like could have some drag. Check settings. Confirm she rolls freely w out pinion in. I did this to a pinion but I had a spool w bad mesh. Also had worn diff that was rubbing inside or mount. Things shifted after a bad wreck.
make sure she rolls free. Try different pinion. Assure mesh is perfect. Depending on ur mount use a paper towel to gap.

I'll double check the mesh with the new pinion. It does roll free and smooth with the motor out as far as I can tell. It's for sure an old spur gear, it's the original one that came with the truck. It's survived like 40 runs so far, I'm kinda impressed.

 

[SrC]

You could try a taller pinion. This may seem contradictory, but this large can motor will handle 20t+ without cogging. I'm guessing during the run, your throttle was maxing out quite a lot?

I've also just started to use the Traxxas 3362 heatsink with mine also it needed to be filed to make way for the roll hoop pin

I agree, You may be maxing out the RPMs on that motor, seeing that your ESC temps are decent. Check the motor bearings, lube them if they are OK. High motor temps will kill the bearings quick. That motor does have strong Magnetic flux at the armature and will be harder to free spin by hand. Normal. ESC caps normally get hot. Check your Caps and make sure none of the Cap tops popped.(split open/failed) Go a bit taller on the pinion. And check temps. Also check the temps of your center diff. An overheated center diff can raise the temps of your motor. But you did say your diffs are fresh built... I normally check center diff temps compared to my motor temps while I am there. Could be diffing out. There is a temp relationship between both. The motor mount transfers heat between the motor and diff. The diff bearings can overheat as well. FWIW. Just some Ideas.

 

[Wraith405]

I agree, You may be maxing out the RPMs on that motor, seeing that your ESC temps are decent. ESC caps normally get hot. Check your Caps and make sure none of the Cap tops popped.(split open/failed) Go a bit taller on the pinion. And check temps. Also check the temps of your center diff. An overheated center diff can raise the temps of your motor. But you did say your diffs are fresh built... I normally check diff temps compared to my motor temps while I am there. Could be diffing out. There is a temp relationship between both. FWIW. Just some Ideas.

Yeah could be a center diff issues. I've taken out the rear diff to double check and I'll check the center here in a bit. The front is fine as well. Bearings all seem good. Like some have said, due to the weird damage to the pinion I could have had the gear mesh too tight.

I went up to a 18T pinion, but due to rain I can't really test it out today. I'll double check the caps. hopefully those are fine, this is a brand new Max6 that came with the motor.