Ford Sigma Engines

Developed on a similar timeline to the Duratec, the Sigma is a range of smaller capacity inline 4-cylinder engine, intended to replace the older Kent-developed Endura and CVH engines. When introduced it featured a number of ‘firsts’, including a ladder type main bearing assembly, and powdered metal forged conrods with split big end bearing caps. Combined with the use of solid mechanical valve followers, allowed the engine to rev very freely to almost 8000rpm – in standard 1600cc format this produced 100bhp and, for it’s capacity, a good broad torque band.

The Sigma engine was originally released in Europe named Zetec-S, followed by Zetec-SE, and then more confusingly renamed as Duratec! Later development included the addition of variable valve timing on both inlet and exhaust camshafts, using engine oil pressure to adjust the timing of the camshaft pulleys, providing an increase in peak power to 125bhp.

The engine has become an increasingly popular swap for the venerable Kent engine, in older Ford classic models. The very light weight combined with good specific output, gives great power to weight increase, as well as the advantages of running a more modern engine. For the same reasons, the Sigma became a good choice in kit and other low volume sportscars, with Caterham using the 1.6 engine alongside the 2.0 Duratec.

In motorsport, the British Formula Ford Championship adopted the Sigma engine in 2005, where it remained in use until replacement by its EcoBoost relation (effectively a turbocharged development of the 1600cc Sigma) in 2012. The engine also had some success in Super 1600 class rally with Fiesta and Puma models, where factory supported M-Sport development saw up to 230bhp extracted from the 1.6 unit. The Sigma remains a popular class engine choice, due to its weight and power.

Based on your requirements, our Ford Sigma Engines can feature:

• Power levels ranging from standard 75-100bhp through to 180bhp+ race spec.
• Ported and polished cylinder head.
• Standard, fast road, or race spec camshafts.
• Forged pistons and con rods.
• Configured for transverse or longitudinal installations, including dry sump systems.

A wide range of new and performance parts are readily available from our trusted supplier network.