Thanks JG, a good read.
Just happened to find this on another forum as well.
YouTube - Pratt & Whitney R-4360 Wasp Major Cutaway
I never really got to operate any radials - apart from a Alvis Leonides in a Scottish Aviation Twin Pioneer a couple of times - and have spent most of my time on turbines. I still treated turbines with kid gloves; I'd warm them carefully and let them cool down as much as possible before shutdown. I'd also make power changes as slowly as possible to slow the temperature cycles.