This is a bit long, sorry
Only a place that actually works on crankshafts will be able to determine if its got any life. Engine machine shops generally do not have that kind of equipment, and those that do, should often be avoided simply because they don't do enough work to be really good at it. When I lived in Minnesota, Crankshaft Supply, in Minneapolis, was known all over the 5 state area, they were that good, and quite reasonable. Even down here in Arkansas, I would not hesitate sending them a crankshaft.
All of that said, what I see in your pics, its doubtful that crankshaft can be saved without welding. The radius areas are totally gouged. Even without that, its simply to rough and if you found a bearing it would fail immediately. Its needs a lot of repair to ever hope to run it again.
Also, diesels, as a rule almost always have crankshafts of forged high grade steel alloy which are then heat treated and nitrided. Its a hardening process to the bearing surface that makes its extremely hard and long wearing. But that hardening is only about .010" thousands of an inch deep, and yours is clearly gone.
I would send the crank off to some reputable crankshaft service company (do this yourself/avoid the local machine shop), and have them inspect it. In the meantime I would try and locate a replacement, if one even exists or is affordable, and wait for the verdict. Welding a crankshaft is not the best option, it defeats the whole purpose of having a forged steel crankshaft. But on an expensive or hard to find crankshaft its often the only affordable option. Done properly its not generally a problem, in fact some companies have actually sold it as an improvement. They grind the surface down much smaller, then build up the surface back up oversize with weld metal of Chromemoly, a very hard alloy. Then its machined back to new limits, oil holes are re-drilled and chamfered, then its heat treated and nitrided.
Also, that rods probably gone too. Those you DO NOT want to weld. The block is full of metal, needs to be thoroughly cleaned and flushed and oil galleries reamed with pipe cleaners. If the crank shop feels it can be welded and repaired, they will request you first have them test the crank for cracks. I would absolutely pay to have that done. They will not guarantee the crank without it.
I think I would spend a few hours on the phone seeing if you can find parts, first. See if you can find a new rod and good used or new crank, and what they will cost. You may find your so far upside down on this you might be better off looking for another motor. I know it sucks. I been burned more than once this way myself a few times.
Maybe someone could throw out the number for that guy up in wisconsin who has used engines? He has a good reputation and from what ive read would be my first choice. Heck, he might even have parts!
