I had a brand new Eureka commercial....(all plastic).Im not sure how similar they are in respect...but mine never had any strange smells after running for long periods.
We haven't had any problems yet and install a good many per week. I use the "off brand" Sanitaire replacement motor (same one used in the Perfect). It is just as good, if not nicer than the original Pancake motor.
MB1981-
Try it and see... but check the motor often just to be sure everything is ok for the 1st month, if all is good then its good to go; if not and you see signs of scorching or excessive wear... swap the motor.