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The HL 230 P30 engine was a very compact tunnel crankcase design, and it kept the space between the cylinder walls to a minimum. The crankshaft was composed of seven “discs“ or main journals, each with an outer race of roller bearings, and a crankshaft pin between each disc. To reduce the length of the engine by an inch or so, and reduce unbalanced rocking moment caused by a normal offset-Vee type engine, the two banks of 6 cylinders of the V-12 were not offset – the “big ends“ of the connecting rods of each cylinder pair in the “V“ where they mated with the crankpin were thus at the same spot with respect to the engine block's length rather than offset; this required a “fork and blade“ matched pair of connecting rods for each transversely oriented pair of cylinders. Usually, “V“-form engines have their transversely paired cylinders' connecting rods' “big ends“ simply placed side by side on the crankpin, with their transverse pairs of cylinders offset slightly to allow the connecting rod big ends to attach side by side while still being in the cylinder bore centreline. This compact arrangement with the connecting rods was the source of considerable problems initially.[39] Blown head gaskets were another problem, which was corrected with improved seals in September 1943. Improved bearings were introduced in November 1943. An engine governor was also added in November 1943 that reduced the maximum engine speed to 2,500 rpm. An eighth crankshaft bearing was added beginning in January 1944 to reduce motor failures. #military #history #combat
