Aha yes.
I've usually installed the cam so that the "narrow round end" goes towards the end of the shaft.
On this machine I've installed type of cam without the round end which I had from before.
One of the original cams was pretty messy because when I was changing the motors I had to pull it out with pliers. It was also sanded to smooth the surface back to normal.

I still don't understand why are the motors getting hot.