2011 Subaru Impreza has been sounding "cranky" for a while; last week, it finally escalated to the point where it sounded like someone was under the hood, banging on the engine with a crow bar.. Fast forward to today, where the shop says "something went wrong inside the crankcase," on the invoice and specifically told me they think it's the valve hitting the crank case and the engine will need to be completely replaced. Are there no other options, nothing else that can be done? Car only has 42,734 miles on it - a complete replacement seems extreme.
Well, the valve can't hit the crankcase directly. The valve can hit the piston directly. Then the piston can get damaged and then parts can fall into the crankcase. No matter the terminology, if there is damage done to the piston and there are parts in the crankcase or laying in the oil pan. Then I would say replacement is necessary. If it was just a bent valve and a piston that is damaged just on top/combustion chamber side, then I would say rebuilding would be possible. However, the man-hours and the parts costs of rebuilding if not doing it yourself would be higher than just replacing it.
I would have them show the damage to you or someone you know, that is good with these matters. Have them boreoscope the spark plug hole and or have the damage exposed with the pan off. See what you and the person you trust thinks, then go from there.