Ford Sigma engine

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1.7L Zetec-S VCT in a 1999 Ford Puma

The Ford Sigma is a small straight-4 automobile engine sold by Ford Motor Company as the "Zetec-SE" and by Mazda as the "MZI". The engine was introduced in the mid-1990s and production continues through the present. Like the SHO V6 and SHO V8, the Sigma was designed with help from Yamaha. Intended for Ford's smaller models, it was intended to replace the older HCS and smaller capacity CVH units.

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, but 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, and obviously the exhaust at the rear.

Introduction and Innovations

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 1.25L (1242cc) capacity, with 1.4 L (1388cc), 1.6 L (1596cc) and 1.7 L (1679cc) derivatives coming later.

Variants

The 1.25 L (1242cc) has an output of 75 PS (73 hp/55 kW) at 6000 rpm and 81 ft·lbf (110 N·m) at 4000 rpm.

The original 1.4 L (1388cc) produces 90 PS (88 hp/66 kW) and 92 ft·lbf (125 N·m), although tougher emissions laws meant the output was reduced to 80 PS (78 hp/59 kW) at 5700 rpm and 91 ft·lbf (124 N·m) at 3500 rpm in the 2002 Ford Fiesta. A de-tuned version was fitted to the 1998 Ford Focus, with a reduced output of 75 PS (73 hp/55 kW) at 5700 rpm and 91 ft·lbf (124 N·m) at 3500 rpm.

The original 1.6 L (1596cc) generates 100PS (98 hp/73 kW) at 6000 rpm and 106 ft·lbf (145 N·m) at 4000 rpm. In 2004, along with the launch of the second generation Ford Focus, torque was increased to 111 ft·lbf (150 N·m) at 4000 rpm.

The 1.6 L was also fitted with variable valve timing, known as Ti-VCT (Twin independent Variable Camshaft Timing), and generates 115 PS (113 hp/84 kW) at 6000 rpm and 114 ft·lbf (155 N·m) at 4150 rpm. In 2007 the Ti-VCT unit was uprated to produce 125 PS (123hp/92 kW) at 6300 rpm and 118 ft·lbf (160 N·m) at 4100 rpm, for use in the new Ford Mondeo.

The 1.7L (1679cc) uses a heavily modified 1.6 L engine block and features Variable Cam Timing on the inlet camshaft. This unit was used exclusively on the Ford Puma, producing 126 PS (124hp/93 kW) and 116 ft·lbf (157 N·m). In 1999 an uprated 1.7 L engine was used in the Ford Racing Puma, producing 154 PS (152hp/113 kW) and 119 ft·lbf (162 N·m).

Zetec RoCam

In 2000, Ford of Brazil developed a cheaper version of the Zetec-SE engine, to compete with the classic VW EA-827 engine series also know as AP (from "Alta Potência, or "High Power", in english) engine in Brazil. It is 8v SOHC instead of 16v DOHC and its body is made of 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 (95 hp) version was released for the Ford Fiesta, to compete with the 1.0 Turbo 16v (112 hp) version of the VW Gol.

In 2003 the Zetec RoCam engine was introduced in Europe, but labeled as Duratec 8v, for the SportKa, StreetKa and Fiesta. Later a 1.3 litre version was also released as an option for the standard model, but 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 alcohol, even mixed at any proportion. This version also featured a high compression ratio (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

  • 1.4 L:
    • 90 PS (88 hp/66 kW) and 92 ft·lbf (125 N·m):
    • 80 PS (78 hp/59 kW) and 91 ft·lbf (124 N·m):
    • 75 PS (73 hp/55 kW) and 91 ft·lbf (124 N·m):
  • 1.7 L:
    • 126 PS (124 hp/93 kW) and 116 ft·lbf (157 N·m):
    • 154 PS (152 hp/113 kW) and 119 ft·lbf (162 N·m):
      • 1999–2002 Ford Racing Puma 1.7

Zetec-Rocam Applications

1.3 L Endura(1299 cc/79 cu in) applications:

1.6 L (1596 or 1597 cc/97 cu in) applications:

  • –present Latin America Ford SportsKa 1.6, 94 PS (93 hp/69 kW) and 100 ft·lbf (136 N·m)
  • –present Latin America Ford StreetKa 1.6, 94 PS (93 hp/69 kW) and 100 ft·lbf (136 N·m)

Zetec-SE as a Crate Engine

The Zetec-SE is also sold by Ford Power Products as a crate engine as the ZSG Range. It is available in 1.4 L or 1.6 L sizes:

  • 1.4 L (1388 cc) (76x76.5 mm), 55 kW (74 hp) at 5000 rpm and 123 Nm (90 ft.lbf) at 3500 rpm
  • 1.6 L (1595 cc) (79x81.4 mm), 74 kW (99 hp) at 6000 rpm and 142 Nm (104 ft.lbf) at 4000 rpm

See also

References