Due to EPA requirements. Most of the shops around here use a spray washer (like a big dish washer). The cleaner has to be compatible with aluminum and cast iron. Unfortunately what cleans rusty iron EATS aluminum.What cleans aluminum doesn't touch rust. Another problem is foaming of the detergent. Wrong combination and you have a LUCY show situation with soap bubbles. (been there). I personally use this system along with a bake and blast system. The bake/blast cleans all visable areas. But, is limited on some internal oil/coolant passages. Also you have to be VERY careful to get the spent blast media out of the casting. A few pieces left in an oil galley and instant bearing failure on startup. The blast media also tends to peen over the tops of lifter bores and exposed edges. These have to be chamfered ar reamed back to size.
The blocks look like fresh from the foundry tho.