1987 toyota supra non turbo?

The front of the engine is making a very annoying ratteling/tapping sound in the same general area as the Crankshaft timing sprockets/ oil pump drive sprockets. (thats what the timing belt goes around and underneath) well i moved the belt connected to the crankshaft pulley which rotated the actuall crankshaft pulley itself about 2 inches, but the timing belt connected to the top 2 camshaft timing sprockets didnt move at all... But the car still runs, it just makes that unhealthy noise. What would cause this? Help me trouble shoot! Someone who actually knows what the hell there talking about! No dumb comments please!!