Weird pit in head near intake valve
 

996 GT3 Cup. Looks like a casting flaw. How the &^%^ does this get past quality control?

I'm concerned about it being a potential detonation spot although everything looks fine around it, and there is no mark on the piston that suggests FOD.

http://forums.pelicanparts.com/uploa...1498073744.JPG
http://forums.pelicanparts.com/uploa...1498073744.JPG
http://forums.pelicanparts.com/uploa...1498073744.JPG

Have the heads been cleaned up with something like a vapour blaster?

It may not have looked this bad when the head was new and the defect may have been full of a non-metallic.

It is possible that the core used to form the ports may have had a small foreign body stuck to its surface..

I would agree that it is undesirable but as it's a hole I would think it is unlikely to generate a 'hot spot' in the same way as if it were sticking out from the surface.

You could try to fill it up with a high temperature repair putty which even if it fell out would be unlikely to do much damage.

High Temperature Adhesives and Epoxies, Ceramics, Insulation, Epoxies and Epoxy

Chris - Engine hasn't been opened while in my possession before. It had a full rebuild 80 hours ago, so it may have been. The "pit" may be smaller than it looks with the carbon making it look worse. We'll see.

I think I'll just have it welded and milled back since the engine is getting a refresh anyway.

I think the head would be best off left the way it is. The heat from welding could cause other problems with the head and the valve seat could be damaged and need to be replaced etc.
The pit will eventually fill up with carbon deposits if you're using gasoline instead of E85 and will probably be harmless.

if you do decide to get it welded the guys at Xtreem cylinder heads do that. They will weld it then remachine it. Theyu filled in the Injector Notch in mine when i had them done and there were several sets of heads in the shop for welding repairs.

TIG only if you're going to repair IMO. That would keep the heat localized as possible.

The most blunted tip for the narrowest arc.

I think what I will do is use a high-temp crack filler to lessen the size. If it drops out it won't harm anything. It was fine for 11,000 km so probably fine to monitor it via boroscope.