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Season:	1973

Capacity:	2,993 cc

Cylinders:	V8

Bhp:	450

RPM:	10500

Technical Specifications

Engine Configuration: V8
Bore: 85.6mm
Stroke: 64.8mm
Engine Displacement: 2993cc
Engine Compression Ratio: 11:1
Crankshaft Angle: 90 Degrees
Crankshaft Type: Flat Plane
Maximum Engine Speed (Redline): 10500rpm
Minimum Engine Speed (Idle): 2000rpm
Valvetrain: 4 Valves per Cylinder, Double Overhead Camshafts.
Cylinder Numbering:

Cylinder Firing Order: 1-8-3-6-4-5-2-7

Power: 336KW (450bhp) @ 10500rpm
Torque: 332Nm (245lb.ft.) @ 8500rpm

Engine Conception: Technical collaboration between Lotus and Cosworth

The Cosworth DFV was designed in conjunction with the Lotus 49, one year after the 3-Litre engine formula was introduced into F1. The first year of the 3-Litre formula resulted in different engine designs, as the teams sought to gain a technological edge over each other, resulting in engines like the famous BRM H16. In fact, it was Lotus designer and team principal Colin Chapman's experience with some of these engines that caused him to approach Cosworth for the design of an engine for the 1967 season.

The DFV was designed by Cosworth as a logical extension to the 1.8L Formula Two engine that became known as the FVA ("Four Valve A-Series"). As the FVA was more than half the displacement of the 3.0L Formula One engine formula, the FVA's original stroke of 69.1mm was reduced to 64.8mm, before the two four cylinder engines were mated at right angles with a common crankshaft, creating the DFV ("Double Four Valve"). Although engines with four valves per cylinder, and even some with five valves per cylinder are quite commonplace today even in road cars, the four-valve layout of both the FVA and the DFV was unproven, with other manufacturers (other than Honda) using it with little success. The valves were laid out in the now-familiar design to promote cross flow, with the intake valves on the right hand side (when looking from the back of the engine to the front), and the exhaust valves on the left hand side.

Upon commissioning the DFV, Lotus would design the Lotus 49 around the engine, that chassis being the first in F1 history to use the engine as a stressed member of the chassis, rather than just as a powertrain, a design element that continues until this day for its advantages in both weight and rigidity.

Engine Finance: Ford agrees...with one condition

While the concept of a limited budget is now completely foreign to the front of the grid of most modern motorsports, the cost of designing, developing and maintaining the five required engines over the course of the season was estimated to be £100,000, a large sum that could not be covered by Lotus alone, thus requiring outside finance. During 1966, when the DFV was to be designed, Lotus, and in fact the rest of the grid, did not run with sponsorship livery on their cars, which made such a sum completely unaffordable by the team.

Although Colin Chapman approached numerous sources to fund the DFV project, eventually Ford - partially due to a link between that company's PR manager Walter Hayes, and Colin Chapmen agreed to finance the engine. However, they imposed on condition on the finance project that would change F1 history forever, making the DFV the most successful engine in history - that Lotus would have exclusive rights on the engine for 1967 only, with Ford retaining the right to sell the engine to any customer from 1968 onwards.

Creating a legend: From Drawings to the Dyno

Lotus wasn't the only major force in F1 racing during the late '60s. In fact, there were many other teams on the grid with the capability of winning races, and in theory, the title. For the 1967 season, the second year of the 3.0L formula, a few of these teams had their own bespoke engines. There were those in the paddock looking skeptically at the V8 Ford-Cosworth engine project, especially since most of the competitive teams had engines with 12 cylinders...or more. Although Brabham would still be using the Repco V8, with eventual success, the machines fielded by Ferrari, Cooper, AAR-Weslake, and Honda would all use V12s. BRM would continue on with the H16, although they too supplied McLaren with a V12 for their M5A chassis.

However, Keith Duckworth (one of the founders of Cosworth, and designer of the DFV) saw distinct advantages in a V8 configuration, namely that an engine with a lesser number of cylinders would suffer from less internal friction, and thus as a result lose less of its power through overcoming this friction. From a packaging point of view - a V8 could in theory be smaller and lighter than a V12, or in BRM's case, the H16. The packaging advantage of the DFV's V8 design was enhanced by the use of aluminium alloy for the engine block. The cylinder liners were made from (much heavier, but stronger) cast iron, and the cover castings on the engine from another lightweight metal, in this case, magnesium.

When commissioning the DFV, Colin Chapman dictated that the engine must produce more than 400bhp (298KW), and the first dynomometer run ran at 408bhp (304KW), thus meeting the specification. After a problem with the oil system was fixed, the engine was handed over to Mike Costin (the other major founder of Cosworth) for testing in a Lotus 49 chassis, the intended destination for the engine. Another problem with vibration at the engine's natural frequency of 8600rpm and the harmonic at 9600rpm was not found until after the engine's first race at Zandvoort, 1967 and was fixed with the introduction of a new camshaft.

The DFV Era: 1967 - 1983

155 Race Wins and 12 Championships. Ford's decision to sell the Cosworth DFV to all manufacturers rather than giving Lotus exclusive use sealed its place in history as the most successful engine in F1 ever. With the current trend of engines lasting only one year before a new design is revealed, this record could very well never be broken. The Cosworth DFV was a constant in F1 racing through from its general release in 1968 until 1983. With the DFV, and its famous drivetrain partner, the Hewland FG400 gearbox (and its derivatives), a new team like Walter Wolf Racing in 1977 could enjoy the same drivetrain as Lotus, and take the fight to famous teams like McLaren and Ferrari. Williams scored its first wins and championship powered by the DFV, and the engine powered both the most successful car of all time - the Lotus 72, and cars that could barely make the grid, like the Amon AF101. In Ford and Cosworth's eyes, all teams were customers, and they all received the same engine, although McLaren, Judd (Engine Developments) and Hesketh were known to perform their own modifications to the DFV.

The DFV won on its first outing, with Jim Clark winning at Zandvoort, 1967 in his Lotus 49. When Michele Alboreto took the flag at Detroit, 1983 in his Tyrrell 011, it would be the last win for the DFV and its subsequent direct development linage, the engine now almost hopelessly outpowered by the turbocharged frontrunners of the grid. During the 1973 season, the DFV powered to victory in every single race in the 15 race season.

The DFV and its relatives outside of F1

Remembering that the DFV itself was derived from two Formula Two engines mated through a single crankshaft, it perhaps isn't surprising that the engine, and its derivatives, were raced in many other categories other than Formula One. These engines were often of different displacements, and in one notable case, was also turbocharged. In alphabetical order, these engines are:

Cosworth DFL: In 1981, the DFV was redesigned in 3.3 and 3.9L forms, and used successfully in endurance sportscar racing.

Cosworth DFW: In 1968, a 2.5L version of the DFV was released as the DFW, as used in the Tasman Series.

Cosworth DFX: In 1975, a DFV engine was destroked to 2.65 Litres, and two turbochargers added, creating the DFX. The DFX became a mainstay of US IndyCar racing, and would power 10 Indianapolis 500 winners.

Cosworth DFY: Direct descendent of the DFV in F1, scoring its last wins in the early Turbo Era years, released in 1982, using a shorter stroke and a DFL bore to liberate more power.

Distant Relatives:

Cosworth DFR: New DFV-based engine released for the 3.5L engine rules used at the end of the Turbo Era of F1, released 1988. Although it used DFV technology, was not a direct development of the DFV. Used until 1992, even though superseded by the HB Series by that time. There is no known connection between the HB series and any subsequent F1 V8 and the DFV, including the 1994 title-winning Zetec-R and the 2.4L V8 being designed for the 2006 F1 season besides their maker.

Cosworth DFS: Development of the DFX, used in IndyCars, using DFR technology as well as DFX, and thus not a direct evolution of the DFX. Eventually replaced by the XB series.

Cosworth DFZ: Interim engine released at the beginning of the 3.5L engine rules in F1 in 1987, prior to the release of the DFR in 1988.

As well as these developments, the DFV itself, when retired from Formula One service due to the grid switching to turbocharged engines, was used as the original engine in the FIA Formula 3000 (named after the displacement of the engine allowed) series, which allowed any 3.0L 90 degree V8. The DFV was retired from F3000 service in 1992. The engine is still used in some entrants of the FIA Series for Thoroughbred Grand Prix Cars.

References

1. 8W: Customer power: The Cosworth DFV story. - http://8w.forix.com/dfv.html
2. Answers.com: Cosworth - http://www.answers.com/topic/cosworth
3. Cosworth: 1973 DFV Spec Sheet - http://www.cosworth.com/downloads/dfv_1973_spec.pdf
4. Wikipedia: Ford Cosworth DFV - http://en.wikipedia.org/wiki/Ford_Cosworth_DFV
5. Grand Prix Cars - Lotus 49 - http://www.ddavid.com/formula1/lotus49.htm

Statistics

Statistic	#	Percentage	First	Last
Number of Grand Prix	293	100%	1973	1973
Number of starts	283	96.59%	1973	1973
Number of finishes	170	58.02%	1973	1973
Number of finishes on podium	45	15.36%	1973	1973
Number of finishes in points	76	25.94%	1973	1973
Number of retirements	113	38.57%	1973	1973
Number of wins	15	5.12%	1973	1973
Number of pole positions	14	4.78%	1973	1973
Number of fastest laps	16	5.46%	1973	1973
Number of doubles (pole position & win)	4	1.37%	1973	1973