There are two type of these pulleys. There is a heavy duty unit with a built-in spacer that requires a large washer. There's a type that requires a separate spacer and a small washer. I've seen the lighter weight version crack, but lighter weight = less wear better engine performance.

From your description it sounds like you have/had the lighter version.
Here are my two spares.

Heavy Version


Light Version


I forget which type goes to which engine.




I've got both types but would prefer to keep them unless you can't find another source.