Well for the sake of not arguing this one...lol...you won't know the damage until you take it apart. And, all engines are handbuilt one way or another, just some are done with a little more finest...hopefully the keyway can be cleaned up and all will be fine. That is why if you haven't done something like this before, find a mechanic who has experience in engine repair/rebuild...not the local grease monkey either...lol....good luck...hopefully the key stock broke...