Hobbsy, it looks like there is a spiral ground into the crank on that picture. Aspeed, my engine case did have a straight groove in the upper part of the case from the carb inlet to the front bearing with a recessed grove around the front of the case just behind the bearing. I assumed this was to lube the front bearings. With the spirals I put in the case from the front to the back, it seems to be helping out quite a bit. It went from drip, drip, drip, drip, to just one or two drops on the lower part of the engine case in about 5 minutes of running. At idle, I don't see any coming out. I am guessing that since the crank was cracked in the intake area, it wore the case slightly and caused excess clearance. With the spiral I ran, it closed up the gap slightly and also helps to pull excess fuel from the front to the back of the engine. It is still getting lube in the front however as I can see a slight seep out of the bearing.