Medusa Afterburner heat issues - RC-Monster Forums

tha5150 · **Medusa Afterburner heat issues -** 02.09.2009, 01:35 PM

Medusa 36x70mm 2300Kv V2 Afterburner Brushless Motor 5mm Shaft was bought brand new 1 month ago. using this in conjunction with a MMM on my Hyper 8 with 14t pinion and 46t spur. i also have a 16t pinion. zippy 4s 5000mah 25c

ok, those are the peices i am using and generating ALOT of heat. i had the 14t pinion on yesterday, went to the local track and was exceeding 200*f within 5 minutes. if i use the 16t pinion it is roughly the same, maybe a bit less. i was trying to use the 14t with alot less woot on straights and turns. basically i was keeping my throttle less than 1/2 the entire time and was able to run for 8 minutes before the heat came back. i dont know what to do. i have the MOD 1 14t and 16t pinion from RCM aswell as the spurs are from RCM. the lipo was fully charged and would generate heat around 120-130, MMM was around 110 and you know they motor temps..

why is this happening? you would think the 16t pinion would generate less heat due to less spinning of the motor but you guys here told me to try out the 14t pinion and it would cool it down a bit. which didnt work. i am only trying to fix this, not point fingers. we are all only here to help.

anyways, someone at the track said that there is a fine line between the gears doing all the work and more heat is built on the motor and the motor building less heat and the tranny does less work. or vica versa or whatever. i am not that knowledgable on these things quite yes, hense why i am on here wrtiting this.

who wants to help!!>??? how can i keep the heat down? should i use the 16t with a 42t spur maybe? i dont know.. you guys tell me. thanks in advance as always.

skellyo · 02.09.2009, 01:44 PM

Can you give us a rundown of the settings on your MMM?

tha5150 · 02.09.2009, 02:06 PM

unfortunately i dont have it memorized. i think it was 70 or 80% punch or something.... disregard that. i honestly have no idea at the moment. im at work.. what do you suggest everything be set at for this buggy and motor?

could the MMM be generating wrong info and making the motor too hot? is this where your getting?

skellyo · 02.09.2009, 02:11 PM

The things I'd be interested in are:

Start power
Timing
Drag brake
Brake

If youre car's driveline is smooth and your gear mesh isn't too tight, I would think that it would be something with the settings on the MMM or a bad motor.

tha5150 · 02.09.2009, 02:23 PM

i do have to say that this motor (i have only had a Fiego 8XL other than this) does not turn freely. there seems to be teeth or something when it turns.
like 10 or 20% turns only, then stops. i think this is normal and when there is electricity in the motor, it frees them up or something, the magnets. i dunno. i think this is normal and i am being a complete noob here. but whatever.
the mesh is dead on. did the ol paper trick and everything. no holes but wrinkled the paper nicely. the spur shows NO signs of wear and is brand new. like new as in yesterday was the only day i used it. this is why i am stuck...

skellyo · 02.09.2009, 02:28 PM

The rotor shaft resitance to turning is cogging torque...it's quite normal for this type of motor.

Any chance your pinion is spinning on the rotor shaft a little bit?

tha5150 · 02.09.2009, 02:33 PM

there is a flattened edge on the rotor shaft where the pinion lock screw tightens onto. so i highly doubt it. plus i put red loctite on it to be sure of this..

one thing i remembered though, happened the other day during testing in my driveway... so you know that hole in the buggy where the spur shows from the bottom? around that hole or slit, there are the 4 screws you screw the motor mount and diff into pace right there. i noticed a HUGE resitance when letting off the throttle and buggy would come to a screetching halt almost. the spur was rubbing against the slit. the inside part of the spur, towards the rear of buggy.. make sense?

here is a pic. not mine, but to show the slit i am referancing.. the part that was rubbing what closer to the back..

skellyo · 02.09.2009, 02:41 PM

Did you by chance install a Kyosho 46T spur on in place of a thinner stock spur? If the spur is rubbing the chassis, that's your problem.

tha5150 · 02.09.2009, 02:49 PM

you know what.. i did...

i ordered 3 from mike.. but here BrianG said it would fit. this is why i ordered them.. so what now, dangit!!!! i have 3 brand new ones

skellyo · 02.09.2009, 03:15 PM

Quote:

Originally Posted by tha5150

you know what.. i did...

i ordered 3 from mike.. but here BrianG said it would fit. this is why i ordered them.. so what now, dangit!!!! i have 3 brand new ones

He may have spaced up his center diff to keep it from scrubbing. I'd take the pinion off the motor and try and turn the spur by hand from the bottom of the chassis. If it doesn't clear at any point, that's your problem. You may also have a warped spur if the gasket didn't seat properly.

Sower · 02.09.2009, 03:36 PM

You can typically still use the plastic spur - you just need to file one side of it down to make sure your drivetrain spins freely. I had to do this with my D8 recently. Had to install it, take it out, file it, and repeat until it was butter

tha5150 · 02.09.2009, 03:44 PM

to both you guys, thank you for your input. i think this may fix the problem..

when i got back to the house yesterday, first thing i did was email Medusa and Jeff has emailed me back. he said to send it back if i want to make sure the motor isnt a dud... from the temps i pushed this thing at, not knowing the temps were this high... ... ... 250+.... :(.... you think i should send it back and request another one? do you think i have killed 1/2 the life of this motor by doing that? hell i am surprised it didnt blow up..

Sower · 02.09.2009, 04:36 PM

Quote:

Originally Posted by tha5150

to both you guys, thank you for your input. i think this may fix the problem..

when i got back to the house yesterday, first thing i did was email Medusa and Jeff has emailed me back. he said to send it back if i want to make sure the motor isnt a dud... from the temps i pushed this thing at, not knowing the temps were this high... ... ... 250+.... :(.... you think i should send it back and request another one? do you think i have killed 1/2 the life of this motor by doing that? hell i am surprised it didnt blow up..

I would send it back - 250 is extremely hot.

bdebde · 02.09.2009, 04:09 PM

I had to file my chassis to make the Kyosho spur fit as well.

Sower · 02.09.2009, 04:35 PM

Quote:

Originally Posted by bdebde

I had to file my chassis to make the Kyosho spur fit as well.

I guess I could have filed the chassis - didn't think about that. Oh well, plastic is easier to file.