The Ford Sigma is a small straight four automobile engine introduced in 1995 by Ford Motor Company. Its first evolution was sold as the Zetec-S (not to be confused with the trim level), then Zetec-SE and finally, in later years, renamed Duratec.Fuel, performance and emissions Ford Fiesta, Ford.co.uk, 21 April 2009. The last upgrade of the engine is named Duratec Ti-VCT. Conceived for Ford's smaller models, the motor was intended to replace the older HCS (a derivative of the even older Kent unit) and smaller capacity CVH units.
Introduction and production As with the SHO V6 engine, development of the Zetec-S was a collaborative effort between Ford, Mazda and Yamaha. The engine's sound profile was refined in Ford's acoustics center in Cologne-Merkenich, Germany. Production of the Zetec-SE was carried out in the Ford Valencia Engine Plant, with Yamaha building the 1.7 L engine blocks in Japan.
When the Zetec-SE debuted in 1995, it included many firsts, including a plastic inlet manifold, a "ladder" style main bearing and crankcase assembly, and big-end bearing caps which are forged in one piece and subsequently split. It also incorporates powder metal connecting rods, which were quite exotic at the time. This feature makes the engine more challenging to rebuild at the end of its working life, since it is not possible to re-machine the bearing ladder as is done with a conventional cylinder block — the entire assembly has to be renewed. Despite this, engine tuners have found novel ways to increase the power of the unit through use of different valves and increasing the compression ratio of the engine through skimming of the cylinder head.
The engine first appeared in the Mk4 Ford Fiesta and the virtually identical Mazda 121 in capacity, with , and derivatives coming later.
Difference between Zetec-SE/Zetec-S/Duratec/Duratec Ti-VCT
The Sigma engine was introduced under the Zetec-S name; after the upgrade it was renamed to Zetec-SE, Duratec and Duratec Ti-VCT. The latest upgrade of Sigma is called Ecoboost 1.6 engine (Not to be confused with the smaller 1.0 or larger 2.0/2.3 engines)
Zetec-S/SE CodeYearsDisplacementBore x strokePower at rpm Torque at rpmCompression1.25 Zetec-S/SE1995– at 5200 at 400010.0:11.4 Zetec-S/SE1998– at 5000 at 350011.0:11995– at 5500 at 400010.3:11.6 Zetec-S/SE1998– at 6000 at 400011.0:1
Zetec-S 1.7 Zetec-S VCT1997– at 6300 at 450010.3:11999– at 7000 at 4500 The engines uses a heavily modified 1.4 L engine block and features Variable Cam Timing on the inlet camshaft. This displacement has only been used in the Ford Puma. A version of this engine was developed for the Ford Racing Puma with only 500 units built.
Zetec RoCam In 2000, Ford of Brazil developed a cheaper version of the Zetec-SE engine, to compete with the classic Volkswagen EA827 engine series known locally as (from Alta Performance, "High Performance" in English) engine in Brazil. It is 8v SOHC instead of 16v DOHC and its block is made of cast iron instead of aluminum. Also, its camshaft is driven by a chain instead of a belt. As a result this engine exhibits rougher behaviour, producing more vibration and noise.
On the other hand, it has a superb torque output thanks to the addition of the RoCam (Rollifinger Camshaft) feature. It's also a much smaller engine than the SE version, which allowed it to be installed on the Ford Ka, replacing the Endura-E engine which by that time was considered underpowered and outdated.
The engine also featured a new patented process for the aluminum head production, which resulted in a better alloy than those produced in Spain and UK, and at a lower production cost.
In 2002 a supercharged 1.0-litre version was released for the Ford Fiesta, to compete with the 1.0 Turbo 16v version of the Volkswagen Gol.
In 2001 the Zetec RoCam engine was introduced in Europe, but labeled as Duratec 8v, for the Ka and Fiesta. Later a 1.6-litre version was also released for the SportKa and StreetKa. The European versions of the engine are produced in the South Africa plant.
In October/2004 a newer bi-fuel version was introduced labeled "1.6 L Flex", capable of running on both petrol and ethanol, even mixed at any proportion. This version also featured a high compression ratio of 12.3:1 and "Compound High Turbulence" chambers, as used on the CHT engine. The 1.0 L Flex runs with a compression of 12.8:1.
Currently, this engine powers nearly all Brazilian Ford models – except those with 2.0 litre engines – in many different variants: 101/106 hp 1.6 L Flex (Ford Ka) 71/73 hp 1.0 L Flex (Ford Fiesta), 69/73 hp 1.0 L Flex after 2012 in Brazil 105/111 hp 1.6 L Flex (Ford Fiesta/ Fiesta Sedan), (Ford Focus), Ford EcoSport)
Applications applications: 2003—2008 Ford SportKa 1.6, and 2003—2006 Ford StreetKa 1.6, and
Duratec After an upgrade to the Sigma, Ford renamed it the Duratec.
CodeYearsDisplacementBore x strokePowerTorqueCompression1.25 Duratec2008– 11.0:1 1.4 Duratec2002– at 5700 at 35002008– 1.6 Duratec2004– at 6000 at 4000
+Duratec technical detailsEngine2008 1.25 Duratec 60/2008 1.4 Duratec 2007 1.4 Duratec 2007 1.6 Duratec VehicleFiesta Mk6Focus MkII face-liftFocus MkII face-liftValve gearDOHC, mechanical tappets, belt driveValves per cylinder4Camshaft driveBeltCrankshaftSpheroidalCrankshaft bearings5Engine managementSiemensFuel injectionEFIIgnitionElectronic distributor-less, wasted sparkEmission controlClose-coupled, closed loop, three-way catalyst with oxygen sensorEmission levelEuro4Lubrication systemPressure-fed lubrication system with full flow oil filterLubrication system capacity with/without filter (L)3.8/3.54.1/3.75Cooling systemWater pump with thermostat and valvesCooling system capacity, incl. heater5.55.8Fuel typeULPFuel grade95 RON
Duratec Ti-VCT The Ti-VCT (Twin independent Variable Camshaft Timing) version includes variable valve timing, and generates more power and torque than non-VVT counterparts. Latest versions comply with the Euro5 emission level.
CodeYearsDisplacementBore x strokePowerTorqueCompression1.5 Duratec Ti-VCT2013– at 6300 at 430011.0:11.6 Duratec Ti-VCT2004– at 6000 at 41502007– at 6000 at 4050 at 6300 at 41002008– at 63002010– at 6000 at 4000–45002011– at 6700 at 4250
+Duratec Ti-VCT technical detailsEngine2007 1.6 Duratec Ti-VCT 2007 1.6 Duratec Ti-VCT 2008 1.6 Duratec Ti-VCT 2010 1.6 Duratec Ti-VCT 2007 1.6 Duratec Ti-VCT 2011 1.6 Duratec Ti-VCT /VehicleMondeoMondeo face-liftFiesta Mk6Focus MkII face-liftFocus MkIIIValve gearDOHC, tappetsDOHCDOHC, twin independent variable cam timingValves per cylinder4Included angle between valves41.75° Valve sizesIntake , exhaust Camshaft driveBeltBelt with dynamic tensionerCrankshaft4 counter-weights Cast iron, 4 counter-weightsCrankshaft bearings 5Engine managementSiemens ECM EMS2101 16-bitSiemensSiemens ECM EMS2101 16-bitFuel injectionEFIIgnitionTower coilElectronic distributor-lessEmission controlHego/CMS dual binary sensorsClose-coupled, closed loop, three-way catalyst with oxygen sensorEmission levelEuro4Euro5Lubrication system Pressure-fed lubrication system with full flow oil filterLubrication system capacity with/without filter (L) 4.1/3.754.1/Cooling system Water pump with thermostat and valvesCooling system capacity, incl. heater 6.05.5Fuel typeULPFuel grade95 RON
Crate engine versions Crate engine versions of Zetec-SE engines are sold by Ford Power Products under the name ZSG Range.
CodeYearsDisplacementBore x strokePower at rpm torque at rpmCompressionZSG 414?– at 5700 at 350011.0:1ZSG 416 at 6000 at 4000
Applications Displacementratingsvehicles, 2008–2017 Ford Fiesta Mk6 at 6000, at 40001995–2002 Ford Fiesta Mk4 1.25 2002–2008 Ford Fiesta Mk5 1.25 2002–2007 Mazda2 (DY) 1.25, 2008–2017 Ford Fiesta Mk6, 1998–2004 Ford Focus Mk 1 1.4 at 5700, at 35002002–2008 Ford Fiesta Mk5 1.4 2002–2010 Ford Fusion 1.4 2002–2007 Mazda2 (DY) 1.4, 1995–2002 Ford Fiesta Mk4 1.4 1997–2000 Ford Puma 1.4 2012–2017 Ford B-Max 1.4, 2008–2019 Ford Fiesta Mk6 (with Ti-VCT), 2013–2023 Ford EcoSport 1.5 2013–2019 Ford Fiesta Mk6 1.5 at 6000, at 40001998–2004 Ford Focus Mk 1 1.6 1999–2002 Ford Fiesta Mk4 1.6 2002–2008 Ford Fiesta Mk5 1.6 2000–2002 Ford Puma 1.6 2002–2010 Ford Fusion 1.6 2002–2007 Mazda2 (DY) 1.6 2004–2012 Volvo C30 1.6 2004–2012 Volvo S40 1.6 2004–2012 Volvo V50 1.6 at 6000, at 40002004–2011 Ford Focus Mk 2 1.6 2003–2010 Ford Focus C-MAX 1.6 2002–2008 Ford Fiesta Mk 5 1.6 (with Ti-VCT) at 6000, at 41502004–2011 Ford Focus Mk 2 1.6 2004–2010 Ford C-MAX 1.6 2007–2014 Ford Mondeo Mk3 1.6 at 6000, at 40502008–2019 Ford Fiesta Mk6 at 6000, at 4000–45002011–2019 Ford Focus Mk3 1.6 2010–2019 Ford C-Max 1.6 2012–2017 Ford B-Max 1.6 at 6300, at 41002007–2014 Ford Mondeo Mk4 1.6 at 6000, at 40002008–2014 Ford Mondeo Mk4 1.6 2011–2019 Ford Focus Mk3 1.6 2010–2019 Ford C-Max 1.6 (with VCT) at 6300, at 45001997–2002 Ford Puma 1.7 at 7000, at 45001999–2000 Ford Racing Puma 1.7
Current use The Ford Sigma engine was produced at Bridgend Ford in Wales, U.K. until September 2020 and at Taubate Engine and Transmission Plant, Taubate, São Paulo, Brazil. Today the Sigma engine is used as the basis for the four cylinder Ford Ecoboost 1.5 litre and 1.6 litre engines. A version was used by Morgan for their 4/4 Roadster coupled to a Mazda transmission from 2009 until the model was discontinued in 2018.
1.25/1.4/1.6 L Sigma These engines in the first generation Focus produced 75 and respectively, but for MkII Focus the 1.4 variant was slightly modified and produced . Both engines have belt driven camshafts and Electronic Fuel Injection systems. They weigh . The 1.6 Ti-VCT was introduced in 2004, it features Variable Cam Timing; this version is used in MkII Focus. A new or EU5 version is used in the MkIII Focus, also a 1.6 L version is used in Ford Fiesta Zetec-S. The Sigma is usually coupled to the Ford IB5 five-speed manual transmission.
Brazil Recently the Sigma engine was present in modern Brazilian versions of the Fiesta, Focus and Ecosport (1.6 L TI-VCT version) and a 1.5 version was used by Ka. This engine was able to use the flex technology.
Power with ethanol: 1.5 L Sigma (non TI-VCT) — IB5+ manual transmission Fiesta (2014–2016) — Ka (2014–2021) — 1.6 Sigma (non TI-VCT) — IB5+ manual transmission (both) and PowerShift (Fiesta Only). Fiesta (2008–2014) — Ecosport (2012–2023) — 1.6 Sigma TI-VCT — IB5+ manual transmission and PowerShift. Focus (2013–2019) — Fiesta (2008–2014) — Ecosport (2012–2023) —
In 2018 the Sigma engine was replaced in all Ford compact/subcompact cars to the newer and stronger "Dragon" engine, displacing 1.5 L with a 3-Cylinder layout and with a power output of 136HP.
Caterham usage Some Caterham Cars use modified Ford Sigma enginescaterhamcars.com such as the Caterham Seven 270, which uses a tuned Sigma engine producing at 6,800 rpm as a modern equivalent to the original Ford Kent Crossflow engine used in the Lotus 7 from 1957 to 1972. Ford Sigma 1.6-litre overview Technical features: a high level of running refinement and low emission levels aluminium alloy cylinder block and head cross flow cylinder head structural aluminium oil-pan for increased engine stiffness individual throttle bodies in place of the standard intake manifold twin overhead camshafts each with five bearings sequential multi-port fuel injection system long life, glass fibre reinforced camshaft drive belt with automatic tensioner state-of-the-art Twin Independent Variable Camshaft Timing (on Ti-VCT variant)
CodeDisplacementBore x strokePower at rpm torque at rpmCompressionFord Sigma 1.6 ? at 6100 at 535011.0:1 at 6900 at 5600Caterham Sigma 1.6 Ti-VCT EU4 at 6000 at 4150
SCCA Spec Racer The third generation of the SCCA Spec Racer, commonly known as the Gen3 was introduced in 2015, and uses the 1.6 L Sigma engine. The engine is sold by SCCA Enterprises as a sealed unit.
Zetec-E comparison