Mark Electric....re your enquiry on heads being painted with heat resistant paint, it may be that the paint may inhibit heat flow to the cooling air, forming an insulating barrier and increasing head temps. I remember from my misspent youth playing around with high performance VW air cooled motors that even a single coat of paint would increase temps by 15-25 degrees....just a thought
Yep, the paint does act to reduce heat transfer, to the air flowing past the fins. It adds a 'thermal resistance' to the system, in effect.
Anodised finishes on aluminium don't have the same effect; they're really only a dye added to the oxide layer on the surface of the aluminium. The oxide layer is made a bit thicker than natural by an electrolytic process, and the dye is adsorbed at the same time.
Anodising can be done as DIY, but that's only really practicable for small parts, as it does require a DC power source. Caswell Plating supply suitable dyes for this process.
