I couldn't tell you for certain how much different it is welding on sandcast engine cases to the later die cast cases, but I have had a successful repair done to a k1 diecast upper case that was severely damaged in battle. It would NOT have been worth the effort if this particular case did not come from a former world record breaking dragbike.
The best I know is Jim French, here on the forums. He owns and has mastered welding equipment that is basically "NASA" level stuff. He has done several repairs for me. Simply outstanding work....
I'd bet if you asked your most skilled welder locally about laser welding perfectly uniform 1/16" wide dimes under a microscope like Jim can, they would ask what you were smoking.
If I had a broken sandcast case, he would be my first call. For sure.
George
