There used to be a machine that would regrind and polish the throw on a crankshaft without removing the engine from the car. The oil pan had to removed of course. The machine was portable and there were machinists who would travel and provide this service to auto repair shops. I saw a machine operator regrind the crankshaft on a 1949 Chrysler. He came to the independent shop where I was a customer and did the job. It wasn’t my car, but I was fascinated that the crankshaft could be machined without removing the engine. This was back in 1963 and I haven’t seen a machine like this since that time. Even back then, on some cars, the oil pan couldn’t be removed without pulling the engine. The 1947 Studebaker was one car where the engine had to be pulled to remove the oil pan.