Here's all I could find on short notice. Its a EMD sales brochure showing an exploded view of the pieces that are welded to form the crankcase. Preston Cook wrote an article about how the crankcases are fabricated about a year ago in one of the rail fan magazines and of course it has lots of pictures.
I found it. Try Carstens "Railfan & Railroad" April 2010 issue, "The Electro Motive 645 Diesel Engine" by Preston Cook. You won't get any better pictures than this unless you get into the plant itself.