heat transferring goo?

I had the same problem with my heatsink. I put on a decent amount of grease but even when I attached the heatsink to the motor again, I noticed it wasn't making good contact. You could try a couple beefy zipties around the motor to clamp the clamp (ha!) to the motor.

[NovakTwo]

We include a tube of heat transfer paste with our conversion kits and offer it as an accessory.