porting a 964
 

When I look into the ports of my 964 heads, there appears to be some ceramic material used to make a smooth entrance. A few ports have some of it missing. Anyone know how I can rework back to spec? thanks

The cast in ceramic inserts are notorious for cracking and braking up. AFAIK there isn't much you can do to rectify the situation. If you insist on identical exhaust port configs you will need to break out the intact ones then port to suit.

The design intent of the inserts is to keep heat out of the head. They do work well in that role when intact.

Parallel with this subject... Could you substitute a ceramic thermal barrier coating instead of the inserts? Sort of like Jet-Hot on the inside.

Any experience with these coatings?

Innerestin' idea Jamie!

Cermaic coating is what the factory uses. If the coating is chipping that means the engine has gotten too hot. It will not hurt anything if the coating is gone

Eric Hood