I'm having a bit of trouble keeping the engine from turning when I try to break the bolt loose. What method did you use to lock the cam sprocket in place when loosening the bolt?

I've tried wedging various things in the sprocket, however I couldn't find a solid way of anchoring/wedging the tool on the head. I also tried having a helper apply opposite force on the crank pulley, but no luck.

Also, how hard is it to loosen the bolt? Mine seems very hard to break loose.

Am I missing something?