loose rocker arm studs?

I put in a new rocker arm stud,by drilling and taping threads into the head,then put in new stud with locktite, On idle i hear a metal tap sound,not like a loose rocker arm,more like a valve tap?Metal to metal,at a random interval? Is it possible I put the stud in too far? as the drill went in pretty easily and about 1" or more,It did not bottom out?Or maybe the valves are not adjusted properly.I checked them all,running,loosen till slight tap,tighten till it stops,then 1/2 to 3/4 more?Really messy way,oil everywhere.