Perhaps those of you with more brushless knowledge then I can help me out, has anyone heard of this ?

I was running my car on a carpet oval, suddenly it was like I lost the pinion gear ? .......... but I didnt......gear was still attached, axle was ok, battery pack was ok....... If I pick the car up, the motor spins but doesnt sound right, when I put the car down, it hardly moved, the motor sounded even worse..... I swapped the motor from my other 10.5 car and made no other changes, and everything was ok so I KNOW something in the motor went bad.

I took apart the motor I had a problem with and didnt see anything visibly wrong, the rotor "looked" ok but my theory is its bad somehow ........... any of you guru's out there know what to look for or have seen or experienced this before.....

Maybe Novak_Two could chime in on this one :-)

Thanks

Rich

Check to make sure the rotor is still all together and the magnet didnt come loose off the main shaft. I had a similar situation and thats what happend to me, the magnet got disloged from the main shaft of the rotor and the motor would spin but when you put the car down it sounded like the diff was slipping or something and the car wouldnt move.

Hi Rich,

I am not technically competent..... ;) but,

Could it have been caused by "free revving" the motor? In which case, the rotor could spin off the shaft, and occasionally break apart.

No the motor was not "free revved" it was on the track under load when the failure occurred and this motor has never been free revved at any time. I have read the warning on the Novak website ....... I figure Charlie will be at the Snowbirds I'll bring it by and he can check it out for sure ......... My buddy told me it was probably the Rotor hays ........ I just wanted to see if there was any other theories....... thanks for the info

could be one of the windings broke,or the hall sensor is going bad..

check the harness good. a guy had one sound like it was gonna blow apart one night and the green harness wire had got cut in a wreck.

Take the rotor out and see if the magnet is loose at all if it is then the rotor is bad... I had this happen to a 13.5 motor that had only 4 runs(2 heats and a practice run) on it in a touring car and it sounds exactly like what you have going on !!!I put a new rotor in and it was fine. I sent the bad rotor back to novak and am waiting for thier answer on replacement..

Motor was never free reved and never run above 140 degrees
It happened during the 3rd qaul of the day however before that the motor was fine in fact it had plenty of rip it just happened all of a sudden. The car stopped moving and of all places middle of a long straight BAMMMMMM fortunatly no damage I suspect when I accelerated for the straight is when the rotor went bad.

Took my motor to Charlie from Novak @ the Snowbird Nationals for him to check it out, the rotor had gone bad, magnet seperated from the shaft, he replaced it and checked out the rest of the motor and im all set ......... under warranty.

Thanks Charlie for the Great Customer Service !

Take care,

Rich

Yupppp I got my replacement rotor last week great service...

I had my LHS send my 17.5 to novak last week due to it felt like it was binding up even with a set of new bearings I am sure they are behind because of snowbirds but I bet they will take care of it in a reasonable amount of time as I havnt had a bad expierience yet with novak...

Had the same thing happen today when testing. Coming up out of the corner when the motor is under a heavy load, and it sounded like I lost a pinion. Pulled the rotor and the magnet slid right off of the shaft. It looks like the glue wasn't set good. It never got above 160 degrees. This was in a brand new 21.5. Guess I'll send the rotor back next week.

I bought a new 17.5 and it was quit as a whistle for the first two 4 minute heats and on the third run I could start to hear little noice. Motor was coming off about 137 and my heat sensor read low as I just compared to a good one so I am definitly going more conservative on gearing to single out any problems with rotor damage. the glue that hold the rotor is probably heating up and weaking the bond on the rotor and therefore warping the rotor and destroying the large bearing . Could it be the glue that holds the rotor on cannot withstand tempertures above 130.

:rolleyes:

when they come out with a rotor ballancer it will be a must have If you want an effiecient motor.

when they come out with a rotor ballancer it will be a must have If you want an effiecient motor.

I took a motor apart yesterday to change bearings. After I put the Motor Back together and Put it in the car I Spun it up. I Heard a noice. I decided to check if I tighten the Motor scews enough. Just as I guessed the scews were not tight. I tighten the screws and the motor was quit as a whisle. You don't want any play in the rotor if your conserned about the Noice.