The Caterpillar C27 is a V12dieselinternal combustion engine made by Caterpillar. The engine is 27 litres (1,648 cu in) in displacement. Each cylinder has a bore of 137 mm (5.4 in) and a stroke of 154 mm (6.1 in). The engine can produce 370–750 kW (500–1,000 hp) at 2100 RPM. The peak torque occurs at an engine speed of 1400 RPM.
This engine began production as Caterpillar 3412. As emissions control was tightened, engine management and combustion chamber is redesigned therefore two different engines emerged: the mechanically controlled C27 and electronically controlled C30. Caterpillar C30 block has been scaled up and C32 emerged. C27 also began to be produced with electronic engine control and management after 2007.