The crankshaft of an internal combustion engine is supported in a split bearing assembly near one end of the crankshaft, with the lower half of the bearing assembly formed in a bearing holder secured to the engine block. An arcuate flange projects axially towards that end of the crankshaft. The flange underlies a crankshaft pulley which drives a timing belt. The arcuate surface of the flange is struck from a center offset from the crankshaft axis in order to provide clearance for the timing belt. The offset construction also improves the joint seal between the oil pan and the engine block.