There's not much to gain from replacing a working Singer motor. When the original motor is regreased, cleaned and rewired they run well. The specs (amps and watts) on the old Singer motors are not much compared to the new replacements, but I have tried a few of them. The new ones can be a bit speedier, but more noisy and there weren't any more punch in the needle fore some reason. I suspect amps on motors are like mAh on recharable batteries (take the numbers with a pinch of salt).
If the old motor needs more than a service or simple repair, you need a replacement of course. The new motors run though, just a bit more noisily. The pedal the come with tend to be the carbon resistor type, and I have clean up old button bakelite controllers that turn out just as good as any new replacements. It doesn't mean that new technology can't be better, but in my experience, you have too serch a bit for the better stuff, and pay a bit more too. There's a limit to how many stitches per minute a 66 can do, but generally its more than speedy enough for me with the original set up.
There's a big difference before and after a 66 is cleaned, greased and oiled, including motor. It should run smoothly and it's generally a low noise model.
Last edited by Mickey2; 02-24-2019 at 10:47 AM.