What Is an EFI 16 Valve DOHC?

Four-cylinder engines started with an eight-valve system with one intake and one exhaust valve per cylinder. Dating to at least 1906, four-cylinders also featured a single overhead cam and a carburetion system for fuel delivery. Valves could number as few as four. As technology improved starting in the 1970s and 1980s, automakers began producing engines with three valves per cylinder – with two intake and one exhaust – and later the four-valve engines. The 16-valve versions had two intake and two exhaust valves per cylinder for better breathing and air/fuel mixture for increased fuel efficiency.

Although there is an abundance of four-cylinder engines with eight and 12 valves, and single overhead cams, the 16-valve dual overhead cam versions have emerged as the performance engine for small cars, including the hot-hatch performance hatchbacks, such as the Volkswagen Golf, the Ford Escort and a wide range of Japanese imports. Ford produced its R4 series in-line four-cylinder engines starting in 1989 and ending when Ford stopped production of its British Scorpio model in 1998. The engine originated as a 2-liter, 8-valve with electronic fuel injection, or EFI, but switched to a 16-valve DOHC EFI engine in 1995. Ford also produced a 2.3-liter 16-valve DOHC EFI engine. Output for the 1995 and later engines ranged from 136 to 147 horsepower. In North America, the Ford Focus came with a relatively small 1.4-liter four-cylinder DOHC with 16 valves and electronic fuel injection. Ford mounted the engine transversely in the front. It featured a high 11-to-1 compression ratio and electronic fuel injection to help it generate 89 horsepower.

Beginning in 1993, the Mazda 626 featured its FE3 four-cylinder engine displacing 2 liters, 16 valves, dual overhead cam and electronic fuel injection. Similar Mazda engines with the same internal features included the 1.8-liter four-cylinder in the Ford Escort GT, the 2-liter motor in the Kia Sportage and a 2.2-liter version that came in the Ford Probe, Mazda B2200 and later 626 models. The 2-liters with DOHC, EFI and 16 valves generated 148 horsepower and 135 foot-pounds of torque.

Nissan produced a series of four-cylinders featuring DOHC, EFI and 16 valves starting with its rear-wheel drive cars in the late 1980s. The CA18-DE engine displaced 1.8 liters and developed 132 horsepower. The CA18-DET turbocharged version generated 176 horsepower in Nissan’s 1989 to 1991 domestic performance cars. Two-liter versions with the same mechanical components were available beginning in 1982 and generated between 152 and 208 horsepower depending on the model. A turbocharged 2-liter version developed 193 horsepower for its 1980s Gazelle RS-X, Skyline RS-X and Silvia RS-X models.