I posted on the gnttype board awhile back asking similar questions but all I heard was crickets. Don't know why... Anyway, I went to a local shop that specilizes in metallic-ceramic coatings and had them prep my new turbo and cylinder heads. Basically, you need to consider heat retention and dissipation. Where do you want to keep heat in and where to do you want it to be released quickly.
I used a heat 'barrier' coating on the valve faces and combustion chamber. I plan to do the same to the piston faces. I used the same approach with the cylinder head exhaust passages. Basically, I want to inhibit combustion heat from entering the water jacket and keep it in the exhaust stream to maintain gas velocity. Coating headers compliments this too.
I haven't done the intake yet but when I do, I want to treat it as if I was a circle track racer. In other words, help the intake release heat in some places and reject it in others. For example, use a heat barrier on the bottom because of the hot oil splash.
I used the same approach for the turbo. I tried to keep the compressor side as cool as possible and keep heat inside the turbine side. (I still plan to use insulating blankets/heat shields on the outside of the turbine housing to help keep the engine compartment cool)
It may sound like I know what I'm doing but I don't. I read a few magazine articles and listened to the shop's suggestions. The engine is not assembled yet so I have no idea if this is worth the trouble and expense.
Sounds good in theory though.
By the way, there are coatings to reject engine oil. Like teflon, I guess. I used this sort of coating on the inside of the engine front cover and plan to coat the crank weights as well. There's also a coating for the piston skirts too but it's name escapes me. It's not ceramic.
You could go crazy with this stuff.
Good luck.
Nick
