Hi Bob,

Like Andy says, the coils are easy to make yourself, an even more effective addition would be brushtab cooling; a piece of brass tubing soldered onto the brushtabs of your motor.

I'll add a few pics to illustrate.

If you're interested, I have a 'how to' and pics of the brass sheet cancooling in the first picture, let me know if you want it.

Regards, Jan.