Abstract: A structural baffle for reducing both crankshaft torsional vibration and oil aeration in an internal combustion engine. The baffle includes a baffle plate and a number of upright members. The baffle plate isolates the oil reservoir from the turbulence generated by the crankshaft, and includes openings allowing oil flowing from the engine to return to the oil reservoir. Preferably, the baffle plate includes a number of oil return towers which align with the oil return ports of the engine to channel oil to the reservoir. The upright members are mounted to the bearing caps both to bolster the bearing caps and to support the baffle plate beyond the throw of the crankshaft.