Cam cap 1 has damages on the cap and cylinder head it self. All other looks fine. Will sanding down the groove and polishing it again will save it?

 

You need to find a machine shop very good at line boreing and have it done. They look pretty poor. The belt was adjusted way to tight for those journals and probably cheap oil/starvation put it to death. Not a good head as far as I could tell you. Those are really deep grooves.

 

How does this happen?

 

usually timing belt too tight and using motor oil with poor pressure resistance.

 

Damn thats pretty rough. Was the engine making any weird noise due to this? I have some decent wear but yea i'd say that definitely needs machined. If u can find a better core that would work too. Might be cheaper.