Ford Sigma engine

The Ford Sigma is a small straight-four petrol engine that Ford Motor Company introduced in 1995 for its smaller models. It first appeared as the Zetec-S, then the Zetec-SE and later the Duratec, and its last upgrade is the Duratec Ti-VCT with twin independent variable camshaft timing. It was meant to replace the older HCS engine, a derivative of the Kent unit, and the smaller CVH units. Development was shared between Ford, Mazda and Yamaha, with production at the Valencia engine plant and the 1.7 litre blocks cast by Yamaha in Japan. It first appeared in the Mk4 Fiesta and the Mazda 121 as a 1.2 litre engine, with 1.4, 1.6 and 1.7 litre versions following. A cheaper single-camshaft 8-valve Brazilian version is known as the RoCam. The Sigma stayed in production at Bridgend until September 2020 and is the basis of the 1.5 and 1.6 litre EcoBoost fours.