i changed the water pump today and i was resetting my timing and when i tried to set the cam gear to TDC it won't turn at all, it doesn't even budge.... wtf is this? the last time i set the timing it was fine and you could turn it but not any more?

 

this is a d16z6 with a stock cam gear

 

do i need to try turning my crank pulling some and then adjusting the cam gear? i've never had a problem with this? has anyone else?