Cylinder head and crankcase manufacturing and assembly techniques

A method of manufacturing a cylinder head and crankcase for a small engine. A crankcase and a cylinder head are cast to close tolerances and include as-cast mounting flanges, which are assembled in face-to-face contact by employing self-threading screws. Bearing recesses are cast into the crankcase. The cylindrical sidewalls of the bearing recesses are provided with as-cast flutes and roller bearings are press-fitted into the bearing recesses.