Check for play in the rotor shaft inside the distributor. If the shaft is able to move off its center it can allow the rotor to impact the inside of the cap and can pretty much look like your pictures.
Oh, yeah,i should have mentioned that. Benny told me the same thing and I actually checked the shaft before he even said anything. When i first saw the shattered rotor,i wondered what the hell could have caused
that to happen and figured a loo
se distributer might do it. Anyways, the shaft had no play or looseness so I think it was just a factor of sitting for ten years or so waiting for someone to resurrect the poor milano!
So don't put off replacing your cap & rotor as it might just be waiting to explode one day as you are headed to venice and give you a big scare that you just killed your happily revving V6!