Although badged as a Duratec, the Focus ST170 engine is actually a Zetec, allbeit with a stronger bottom end and variable inlet cam timing (VCT). Learn about the Ford Zetec 16 valve DOHC engine, the differences between each series, and which Ford's they were fitted to. General description - Zetec engine. The Zetec engine, (formerly Zeta), is of sixteen-valve, double overhead camshaft (DOHC), four-cylinder, in-line type, mounted transversely at the front of the vehicle, with the (clutch and) transmission on its left-hand end (see illustrations). NBhiVV.

ford focus 1.6 zetec engine diagram