The Family 0 is a family of inline piston engines that was developed by Opel, at the time a subsidiary of General Motors, as a low-displacement engine for use on entry-level subcompact cars from Opel/Vauxhall. These engines feature a light-weight cast-iron semi-closed deck engine block with an aluminum cylinder head. The valvetrain consists of chain-driven hollowcast dual overhead camshafts (DOHC) that actuate 4-valves per cylinder via roller finger followers with hydraulic tappets. These engines also feature a 78 mm (3.1 in) bore spacing and fracture-split connecting rods.