On the d16z6 head..the cam gear has a peice in the middle of the gear with a line in the middel of it....when my vavles hit the piston and bent the valves I took off the head and replace ALL of the valves...put the head back on the block and now I am at the point to set the timing...I heard that it should be set to 16 degrees before TDC..or can I set both the block and the head to TDC??

Question 2:
Ok..while setting the head to TDC, the cam gear will only move a little then it will not move anymore...a sign of the valves hitting the piston...I took off the cam gear and I saw that the "peice" inside the camgear had spun...what would cause this??

Question3: I have a mini-me swap with a6 block and z6 head...I am using the y8 timing belt..I took off the tensioner and when i try to spin it..barely spins at all..I bought a new one and the new one spins ahell of alot better then the old one, I am figuring that it was a bad tensioner that caused the belt to loosen, that cause the cam gear "peice" inside to spin, and caused the valves to hit the piston...what do you think of all that...whew :::whipping sweat off of forehead:::