Ford I4 DOHC engine

The Ford I4 DOHC engine was a 4-cylinder inline internal combustion engine with twin overhead camshafts, produced by the Ford Motor Company, at Dagenham Engine Plant. First with 2.0-litre 8-valve version, in later models with 2.0/2.3-litre 16-valve version from 1989 to the end of production of the MK2 Ford Galaxy in 2006. It powered various Ford models during this time, but was most well known in the rear wheel drive "Twin Cam" variants of the Ford Sierra, and Ford Scorpio. Despite being built for the company's larger RWD models, Ford unusually employed the engine in the front wheel drive Galaxy and sport version of Escort named RS 2000 16v.

The I4 was originally designed to replace the ageing 2.0L OHC Pinto engine, derivatives of which had powered most of Ford's four-cylinder rear-wheel drive cars since the early 1970s, and which was now lagging badly behind the competition in terms of power output, efficiency and refinement. Equipped with a newly designed twin-cam cylinder head but still only 8 valves, and a "square" 86x86mm bore and stroke, the new I4 unit was launched in the Ford Sierra and Ford Scorpio, mated to the newly designed all-synchromesh MT-75 5-speed manual transmission, or the existing A4LD four-speed automatic. The engine itself received mixed reviews, being seen as an improvement over the Pinto, but not the leap forward one might have expected. With the Sierra in its twilight years by 1989 and the new Mondeo destined to replace it in 1993 powered by the newer 16V Zetec unit, it is probable that Ford considered the I4 would have a relatively short production life and so only put limited investment into the unit, even though it eventually remained in production until 2006.

Although front wheel drive, and powered by a separate range of transversely mounted engines, the smaller Escort model was to play host to the next major incarnation of the I4. In 1990, the mkV Escort had been launched to disappointing press reviews, and Ford were looking to boost the image of this critically important range and steal sales from arch rivals Vauxhall and VW who were doing very well with big bore GTE/GTI badged versions of their family hatches.

...
Wikipedia