MMM problems

Hi all,

I'm somewhat a newbie to RC so bear with me. I have been having a problem with my Momba Monster setup. I currently have a v3 MMM esc and an equvlient motor to the one that comes with the e-revo BE, I am running a 5s lipo 30c 4000mAH (Eagle Power). This is installed on a Cen Matrix TR FRE, brushless converted with the rc monster motor mount. I recently destroied my second motor (pics below) the first one i was running 11/66 or 62 cant remember whatever comes stock on a the truggy. The second time I was running 11/52 motor temps were good and esc fan would never come on, also i was running with the body off, so airflow was not a problem. I mostly us the truggy for bashing and was planning to start taking it to the track but am now getting very frustrated... any help would be very much appreciated.
thanks in advance.

-Justin