Shimming Starter?

[WankelsRevenge]

So I got my new starter installed and it went in pretty much just like they all do, but now I have another problem. When cranking it has an odd sound to it, and then right when it catches theres a wicked grinding sound, similiar to if you try to start your car when it's allready running. Im thinking it may not be aligned right and I need to put a shim or two in it, but unfortunatly I know nothing about shimming starters. Anyone with any experiance here I can use all the help I can get, I dont want to majorly damage my flywheel before I can get this fixed.