Abstract: An internal combustion engine includes a crankcase and an upper oil pan. The crankcase includes a plurality of main bearing caps extending between a pair of side walls, with openings in the main bearing caps and in the side walls. The upper oil pan is configured to sealingly engage the crankcase, and includes openings therethrough, which align with the openings in the main bearing caps and the side walls when the upper oil pan engages the crankcase. Fasteners structurally tie the upper oil pan to both the crankcase side walls and the main bearing caps. The engine may further include a lower oil pan defining a sump and attached to the upper oil pan. The upper oil pan preferably includes an oil filter manifold, an oil scraper, and a plurality of oil passages, while also providing a windage tray.