A、 The section of the engine which contains the sleeve, master and link rod assemblies, cams, cam drive gears, tappet guides, rollers, carriers, etc.
B、 The section of the engine which contains the crankshaft, master and link rod assemblies, cams, cam drive gears, tappet guides, rollers, carriers, etc.
C、 The section of the engine which contains the crankshaft, master and manifold assemblies, cams, cam drive gears, tappet guides, rollers, carriers, etc.