If built according to the plans, the engine sump becomes a permanent part of the crankcase once the tubes are screwed into the crankcase and then silver soldered to the sump body. I know this has worked fine for many builders in the past, but I was uncomfortable doing this. What if the threaded connections leaked oil? What would happen if the sump were damaged? To avoid these and other potential problems with a permanently attached sump, I decided to make it removable.