The crankcase's upper section has an AluSil insert in a magnesium alloy, with the timing cover part of the engine block. The AluSil cylinder bores lack iron liners, preventing machining, but the deck surface can be planed. The insert has threaded bores for transmission, cylinder head, and crankshaft main bearing bolts, and includes coolant passages. The lower crankcase section is a magnesium bedplate structure with sintered steel inlays for bearing support. A liquid sealant is injected into a groove between crankcase sections. The crankshaft is cast iron with 7 main bearing journals. Connecting rods are cracked for bearing cap centering, have pairing codes, and are weight categorized. Pistons are aluminum with 4 valve reliefs and oil spray jet cooling.