MORE commonly associated with BMW these days, the inline six-cylinder was once a staple engine for all three Australian manufacturers – Chrysler with the Valiant’s “slant six” and “Hemi six”, Holden until 1986 and Ford since the first Falcon of 1960.
Packaging requirements and modular engine designs eventually spelt the end of the straight six for General Motors in the mid-1990s, and it is only a matter of time before the Blue Oval world’s last straight six engine is also relegated to history.
Known as the “250 Crossflow”, Falcon’s staple inline six displaced 4.1 litres (250.2 cubic inches) in the XY, XA, XB, XC, XD, XE and XF, before the 1988 EA’s 3.9-litre (238ci) fuel-injected six introduced a SOHC cylinder-head. Capacity increased to 4.0 litres (244.1ci) for the 1992 EB Series II, and VCT variable valve timing was introduced in September 1998 with the AU (XR6).
Ford launched an overhauled version of its so-called Barra six in September 2002, when the $500 million BA Falcon – more a redesigned model than a midlife facelift for its poorly received AU – emerged featuring a new DOHC 24-valve cylinder-head and peak outputs of 182kW and 380Nm of torque.
The same engine was fitted to the all-new Territory SUV of June 2004 and, for the subsequent BF Falcon and SY Territory upgrades, received its final update to deliver 190kW and a class-leading 383Nm of torque for both models.
Left: Duratec 35 aluminium block.
A number of V6 engine options are available to Ford Australia when the venerable Ford straight six is eventually retired, but the most likely to succeed it is the latest version of FoMoCo’s 3.5-litre Duratec V6.
Revealed recently as the engine that will power Ford’s Territory equivalent in the US, the Freestyle-replacing 2008 Taurus X seven-seat crossover, the Duratec 35 produces 198kW at 6250rpm on 87-octane unleaded fuel – 30 per cent more than the previous Duratec 35 engine.
Significantly, Ford claims its all-new six-speed automatic transmission, which will replace the Freestyle’s continuously variable transmission, was designed in tandem with the newest Duratec V6.
If chosen by Ford to power Falcon and Territory, expect the Duratec V6’s new six-speed auto to replace both the German ZF six-speeder found in premium Falcon/Territory models and the five-speed auto that itself will replace the current four-speed in the 2008 Falcon.
A 60-degree DOHC V6 with variable intake valve timing, the all-aluminium Duratec 35 is manufactured at Ford’s Lima engine plant in Ohio, revs to 6700rpm, features 10.3:1 compression and produces 339Nm of torque at 4500rpm.
Unlike Falcon’s current long-stroke engine, the Duratec V6 features oversquare cylinder dimensions, with a 92.5mm bore and 88.7mm stroke.
The Cyclone-codenamed Duratec 35 first appeared in 2006 and, like Mazda’s and Jaguar’s (AJ-V6, which is the only other modern V6 in the Ford stable) 2.1, 2.5 and 3.0-litre V6s, is based on the 3.0-litre Duratec 30. It is said to offer up to 224kW and will eventually spawn a 3.7-litre version.