Mechanicals
Unlike many of its rivals, the Sierra retained rear-wheel drive, albeit with a modern, fully independent rear suspension, departing from the Cortina's live axle.
In the beginning the Sierra used engines and transmissions from the Taunus / Cortina. The engines were of two types, the SOHC Ford Pinto engine in 1.3, 1.6, 1.8 and 2.0 L displacements, and the OHV Cologne V6 engine (in 2.3, 2.8, and 2.9 L capacities). Towards the end of the 1980s due to tightening emission standards, the Pinto engine began to be phased out-the 1.8 in 1988 replaced by a 1.8 CVH, the 2.0 in 1989, replaced with the Ford I4 DOHC engine and the 1.6 in 1992, replaced by the 1.6 CVH first seen in the Escort in 1980, described as a "CFi", a single point fuel injection system with a catalytic converter.The 2.9 L Cologne engine was available in the Sierra XR4x4 and the Sierra Ghia. Models with the 2.0 L and Cologne V6 engines had an option of a limited slip differential. Models built until 1989 used the type 9 gearbox that had been used in the Cortina, with the exception of 2WD Cosworth models that used the T5. The T5 had several variations, most were internal. This was basically the same transmission used in the Ford Mustang. The .80 overdrive gears were the weak link. It was later superseded by the MT75 unit (for DOHC, 4X4 and V6 models). All Sierras had rear drum brakes, except sporting models (2.0iS (some), 2.0 GLX & GLS, XR4x4, Sierra Cosworth, other special/sporting models inc 2.0i 4x4) and models with anti-lock brakes. American versions meanwhile were sold only with a 2.3 L four-cylinder turbocharged version of the Pinto engine.
The Sierra also had a diesel option on the engine, namely at launch the 2.3 L normally aspirated 67 PS (49 kW; 66 hp) diesel made by Peugeot. This engine was also used in contemporary Granadas and whilst reliable and economical it made an unrefined, noisy and very slow vehicle, but remained a popular option for Taxi firms. This was later superseded in 1990 by a 1.8 L turbocharged powerplant of Ford's own design which offered better response times and slightly more power.
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