Internal Ventilation for Crankcase
The familiar external system for ventilating the engine crankcase was first converted to an internal ventilation system for the X 18 XE1 petrol engine. The continuous, separated ducts in the cylinder head, cylinder block and oil pan were integrated for the blow-by gas and the oil return, as shown in Illustration H 2709.
The external sources for potential oil leaks are removed because of the internal ventilation of the crankcase.