Timing belt on aux pulley

[TheBandit]

Our belt is running on the front edge of the aux pulley. We do have shims on the aux shaft but it still runs on the edge. Anyone ever run shims to space the pulley? This started when we changed heads. Same pulleys just a different head. I don’t think the belt will come off, it just makes me nervous. Any advice?

[Jb35]

Make sure cam pulley belt quide is on and turned the right way. Make sure belt isn't too tight. I've never run shims on the aux pulley before. Make sure all pulleys match as far as square tooth or round tooth. Check belt tensioner for any play or bent. I had one the tensioner was a little bit bent and it ran the belt off.

[dave41]

cylinder head not cut true. without belt guides belt will run off