GM Family Z engine

The GM Family Z engine is a turbocharged common rail diesel engine that General Motors Korea has produced since 2010. It replaced the VM Motori RA 420 diesel in a number of General Motors applications, including the diesel versions of vehicles sold as Chevrolets for North America, Daewoos for Korea, Opels for Europe and Holdens for Australia. It has a chain-driven dual overhead camshaft valvetrain with hydraulic tensioners, twin balance shafts in the oil pump and an electronically controlled variable-geometry turbocharger. Its common rail system works at pressures of up to 1,800 bar, and the compression ratio of 16.5 to 1 was lowered to 16.3 to 1 for 2012, together with a new intake port that increases air flow and swirl control and improves nitrogen oxide emissions and performance.