It's usually reserved for big commercial engines that replacement parts tend to be extremely expensive- - - - -patching up an automobile block or head is usually prohibitively expensive unless the part is extremely scarce. The machine shop where I ran the connecting rod reconditioning department sort of specialized in commercial Diesels, and they sublet their crack repairs to a company called "Diesel Cast Welding". The technology exists, and has actually improved over the past few decades, but it comes at a price that will make your checkbook need CPR!
Jerry
