pretty sure those castings are a aloominum / magnesium alloy . I have a friend who specialises in welding and repairs to engine cases . It can be done , and 're machined so youse never know it had happened The big but here tho , is that the engine would have to be stripped to bare cases to do it . He himself would advise you to look for a set of cases on eBay . If you don't sleep for a couple of nights and devote your days to clever ideas , I'm pretty sure you will eventually come up with a brilliant plan ! It really pains me to read this , as it is exactly the kind of mistake I would make . why are the simplest **** ups to make , usually the most devastating?