For reference, the crankshaft pulley I assume Honda installed on my NSX at the factory and the new one I just had installed with the part number 13811-PR7-A02 both look the same and they look different than what ffffanman posted above. ffffanman’s looks sturdier.
In both my old and new crankshaft pulleys, the rubber dampener “donut” inside is attached to the flat face of the pulley that you can see from the wheel well. There’s a gap between the dampener and the outer metal surface that holds the belts and the inner metal surface around the splines. You can see the sunlight shining down into those open channels in the pictures below. The dampener inside the pulley ffffanman sawed in half, on the other hand, is attached to the inner surface that goes over the splines, not to the flat side that faces the wheel well.
I don’t know why they’re different, but they are. Also, both my pulleys have twelve little holes on the flat side facing the wheel well that are filled with rubber (securing the rubber dampener to the metal pulley) while ffffanman’s has eight much bigger holes on the flat side that aren’t filled with rubber (since the dampener is secured to the pulley in a different place). The dampener in my pulley is mainly rubber with just a ring of metal on the side facing the engine and ffffanman’s is mainly metal with just a tube of rubber inside. ffffanman's also looks like it stands off further from the engine than mine, which might change the belt geometry.
In any case, the pulley ffffanman sawed in half looks like it would last longer than the pulley that just failed in my car.
ffffanman - does the new pulley on your car with the part number 13811-PR7-A02 look like the sturdy old one you sawed in half or more like mine?
Pictures of my old and new pulleys are below,
here , and
here.