I am have just taken my crankshaft out to have polished. I noticed that there are grooves cut into the front and back of the crank. The grooves were caused by the front and the rear main seal. I know a common fix for this a sleeve, they work well on daily driven cars but I would like to know if anyone has done this in a race application. The engine is a 94 1.6 vtec honda sohc. The engine was not leaking oil from either seal and I am a little worried about future problems.