Ford Sigma engine


The Ford Sigma is a small straight-4 automobile engine introduced in 1995 by Ford Motor Company. Its first evolution was sold as the Zetec-S, then Zetec-SE and finally, in later years, renamed Duratec. The last upgrade of the engine is named Duratec Ti-VCT. Conceived for Ford's smaller models, the engine was intended to replace the older HCS and smaller capacity CVH units.

Introduction and production

As with the Ford Taurus SHO's SHO V6 engine, development of the Zetec-SE was a collaborative effort between Ford and Yamaha. The engine's sounds were refined in the Ford 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 engines in Japan.
When the Zetec-SE first arrived in 1995, it included many firsts, such as 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 and notable at the time. 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-SE name; after the upgrade it was renamed to Duratec. The latest upgrade of Sigma is called Duratec Ti-VCT.

Zetec-S/SE

Zetec-S

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. The
engine has only been used 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 AP 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 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it to be installed on the Ford Ka, replacing the Endura-E engine which by that time was considered underpowered and outdated.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 "1.6L Flex", capable of running on both petrol and ethanol, even mixed at any proportion. This version also featured a high compression ratio of 11.8:1 and "Compound High Turbulence" chambers, as used on the CHT engine.
Currently, this engine powers nearly all Brazilian Ford models – except those with 2.0 litre engines – in many different variants:
applications:
Ford upgraded Sigma and renamed it to Duratec.
CodeYearsDisplacementBore x strokePowerTorqueCompression
1.25 Duratec2008-11.0:1
1.25 Duratec2008-11.0:1
1.4 Duratec2002- @ 5700 @ 350011.0:1
1.4 Duratec2008-11.0:1
1.6 Duratec2004- @ 6000 @ 400011.0:1

Engine2008 1.25 Duratec 60/
2008 1.4 Duratec 		2007 1.4 Duratec 2007 1.6 Duratec
VehicleFiesta Mk6Focus MkII face-liftFocus MkII face-lift
Valve gearDOHC, mechanical tappets, belt driveDOHC, mechanical tappets, belt driveDOHC, mechanical tappets, belt drive
Valves per cylinder444
Camshaft driveBeltBeltBelt
CrankshaftSpheroidalSpheroidal
Crankshaft bearings555
Engine managementSiemensSiemensSiemens
Fuel injectionEFIEFIEFI
IgnitionElectronic distributor-less, wasted sparkElectronic distributor-less, wasted sparkElectronic distributor-less, wasted spark
Emission controlClose-coupled, closed loop, three-way catalyst with oxygen sensorClose-coupled, closed loop, three-way catalyst with oxygen sensorClose-coupled, closed loop, three-way catalyst with oxygen sensor
Emission levelEuro4Euro4Euro4
Lubrication systemPressure-fed lubrication system with full flow oil filterPressure-fed lubrication system with full flow oil filterPressure-fed lubrication system with full flow oil filter
Lubrication system capacity with/without filter 3.8/3.53.8/3.54.1/3.75
Cooling systemWater pump with thermostat and valvesWater pump with thermostat and valvesWater pump with thermostat and valves
Cooling system capacity, incl. heater5.55.55.8
Fuel typeULPULPULP
Fuel grade95 RON95 RON95 RON

Duratec Ti-VCT

The Ti-VCT 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 strokePowerTorqueCompression
1.5 Duratec Ti-VCT2013- @ 6300 @ 430011.0:1
1.6 Duratec Ti-VCT2004- @ 6000 @ 415011.0:1
1.6 Duratec Ti-VCT2007- @ 6000 @ 405011.0:1
1.6 Duratec Ti-VCT2007- @ 6300 @ 410011.0:1
1.6 Duratec Ti-VCT2008- @ 6300 @ 410011.0:1
1.6 Duratec Ti-VCT2010- @ 6000 @ 4000-450011.0:1
1.6 Duratec Ti-VCT2011- @ 6700 @ 425011.0:1

Engine2007 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 /
VehicleMondeo
Mondeo face-lift
Fiesta Mk6		Focus MkII face-liftFocus MkIII
Valve gearDOHC, tappetsDOHCDOHC, twin independent variable cam timing
Valves per cylinder444
Included angle between valves41.75°
Valve sizesIntake, exhaust
Camshaft driveBeltBeltBelt with dynamic tensioner
Crankshaft4 counter-weightsCast iron, 4 counter-weights
Crankshaft bearings55
Engine managementSiemens ECM EMS2101 16-bitSiemensSiemens ECM EMS2101 16-bit
Fuel injectionEFIEFIEFI
IgnitionTower coilElectronic distributor-less
Emission controlHego/CMS dual binary sensorsClose-coupled, closed loop, three-way catalyst with oxygen sensorClose-coupled, closed loop, three-way catalyst with oxygen sensor
Emission levelEuro4Euro4Euro5
Lubrication systemPressure-fed lubrication system with full flow oil filterPressure-fed lubrication system with full flow oil filter
Lubrication system capacity with/without filter 4.1/3.754.1/
Cooling systemWater pump with thermostat and valvesWater pump with thermostat and valves
Cooling system capacity, incl. heater6.05.5
Fuel typeULPULPULP
Fuel grade95 RON95 RON95 RON

Crate engine versions

versions of Zetec-SE engines are sold by Ford Power Products under the name ZSG Range.
CodeYearsDisplacementBore x strokePower@rpmtorque@rpmCompression
ZSG 414?-@5700@350011.0:1
ZSG 416?-@6000@400011.0:1

Applications

Current use

The Ford Sigma engine is produced at Bridgend Ford in Wales, U.K. and at Taubate Engine & Transmission Plant, Taubate, São Paulom, Brazil. Today Sigma engines are used by Focus, Fiesta, C-Max and Mondeo. A version is used by Morgan for their 4/4 Roadster since 2009, albeit coupled to a Mazda transmission driving the rear wheels.

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 / 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 and a 1.5 version was used by Ka. This engine was able to use the flex technology.
Power with ethanol:
Some Caterham Cars use modified Ford Sigma engines 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:
CodeDisplacementBore x strokePower@rpmtorque@rpmCompression
Ford Sigma 1.6?@6100@535011.0:1
Ford Sigma 1.6?@6900@560011.0:1
Caterham Sigma 1.6 Ti-VCT EU4?@6000@415011.0:1

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

The Zetec-SE has no common parts or design with the larger Zetec-E engines apart from the name. This gives rise to some confusion since it suggests that they are members of the same family when they are, in fact, completely different. Zetec-E units are mounted transversely with the inlet manifold at the rear, whereas the Zetec-SE units are mounted with the inlet manifold at the front.

Replacement

In 2012 Ford replaced the Sigma engine with a brand new 3-cylinder 1.0-litre EcoBoost engine for some markets and models. The new engine provides more power and torque with less fuel consumption and lower Carbon dioxide| emissions.