I had the combustion chamber, exhaust valve radius and exhaust ports ceramic coated by Swaintech. I did not have the intake valve radius or intake ports coated.

Before coating, the heads were already fully machined, including a multi angle valve job and valve seat lapping. Now, the exhaust valve seats are coated in ceramic, and so is the lapped part of the valves.

Am I supposed to lap the valves again to bring back metal-to-metal contact? Or am I supposed to assemble the heads with the ceramic coating left intact? My understanding is that the valve gets cooled through contact with the valve seat. If there's ceramic in the way, doesn't that create an insulating effect? I understand that the ceramic coating is intended to help prevent the valve from absorbing heat, but there's still a heat buildup over time that needs to go somewhere.

The reason I'm asking here instead of calling Swaintech is that they're closed until Monday, and I'm itching to start assembling my heads this weekend

 

I would pick up some grinding compound and get that metal on metal back. Ceramic acts as an insulator. It's true that the heat is pulled out by the seat and stem.

I'd contact swaintech to be sure.

 

what did swaintech say?
I know its an old thread but was looking at pics and was wondering the same thing about the seats