athearn Tunnel motor shell rubbing on motor

[NYSW F45]

I just found my old athearn HO tunnel motor project. While swapping the newer body on it i noticed that the shell just barely fits over the motor. Is this going to be a problem if the motor gets hot? are there slimmer motors?

 

[ThoroughBreed]

Motor heat isnt really a problem, but the noise is gonna increase. I've lightly sanded the inside of the shell to put a little space in between the motor and shell so as not to amplify the vibrations.