The crankcase is the engine’s skeleton – it holds the cylinders, numerous pipes and hoses run through it and innumerable engine components are mounted on it. But it does not only hold the other components, it also has to withstand enormous forces generated by pressures produced by combustion and the movement of the pistons. On top of this there is the oil fl owing through the crankcase at temperatures up to 100°. Extreme pressures and temperatures are one reason why absolute precision is required in production for a crankcase to be capable of withstanding the stresses. Equally important are the tolerances of a few hundredths of a millimeter. The manufacturing process demands extensive skills and experience. So how is a crankcase produced?
A 20-cylinder crankcase for a Series 4000 engine weighs 2.4 tonnes in unfinished condition when delivered from the foundry. To the layperson it might appear ready for assembly at that point. After all, it already has the cutouts for the cylinders and piping. However, you would soon find out in the assembly process that the matching attachments do not fi t. The crankshaft would rub, bolts would not hold. There are four production phases taking four to five days between arrival of the anthracite-gray unmachined casting and completion of the shiny silver crankcase ready for assembly.