@@heavymetalrc7520 Before grinding the valves with a special paste, as he did, it is necessary to give them a profile shape. This is done with a milling cutter. Then the work will be done correctly.
I just came from KT3406E channel, jesus what a mess this is, they didn't even try to be clean. Don't drain the oil just tip over the engine on the ground without the head and move on with live