You shave too much off the head, cam timing will change unless you have adjustable cam to counter back....
Before i skim my 4G13 head, i saw below the side got marking i think is the skim limit that your can go. That marking is about 1 mm, and i just skim is flat. Up until now my car does not face any overheat issues, even i rev to 6000 rpm and drive up to 180 km speed. Refer attach picture.
You can still adjust with your timing belt tensioner.You shave too much off the head, cam timing will change unless you have adjustable cam to counter back....
In that case, i leave my spar head original for my future turbo setup. As you have skim to max like my already overheat and warped the head.Mine was skimmed to the marking max also
If skim a little, Belt tensioner will help, but too much off, if not mistaken the cam angle will differs slightly...You can still adjust with your timing belt tensioner
looks like low comp turbo piston design...easy to BOT laterHere is my 4G12 low compression ratio piston install my my 4G13 photo for sharing.