Cosworth DFV

The Cosworth DFV is an internal combustion V8 engine, produced originally for Formula One racing by Cosworth. The "DFV" stands for Double Four Valve. Four Valve is from the engine having four valves per cylinder, and the Double refers to the entire engine is a double version of a previous in-line, four cylinder engine made by Cosworth, called the "FVA".
For a number of years, the engine was the dominant power plant in Formula One, including winning every race in the 1973 Formula One season. It was succeeded by the Cosworth DFY mid-way through the season.
==History==
The DFV had three major upgrades over its life in the top formula, with the development of first the DFY and then the DFZ, followed by a major redesign to produce the final DFR type.
The project was revealed by Hayes in a PR launch in Detroit at the end of 1965, but the engine was not ready until the third race of the 1967 season, on the 4 June at Zandvoort. Its debut proved successful. Graham Hill, who was in the team at the specific request of Ford and Hayes, put his DFV-powered Lotus 49 on pole position by half a second and led for the first 10 laps but was then sidelined by a broken gear in the camshaft drive. Team-mate Jim Clark moved up through the field in his identical car and came home to win. However, this dominant performance belied a serious fault in the timing gear.Howard, K. (2007) Relative values. Motor Sport, 83(7), 40–43. Clark took three more wins that season, but reliability problems left him third in the Drivers' Championship, 10 points behind champion Denny Hulme. The progress of the engine was documented in a film produced by the Ford Motor Company's film section, entitled 9 Days in Summer.
Initially, the agreement between Ford, Cosworth and Lotus was binding on all parties, and Ford as the funder had no plans to sell or hire the DFV to any other teams. However, it occurred to Hayes that there was no competition: the Ferrari engine was underpowered; the BRM complex and too heavy; the Maserati unreliable; the Honda overweight; while Dan Gurney's Weslake motor was powerful but unreliable. Only Brabham's Repco V8 engine provided a usable combination of power, lightness and reliability, but its age and design left little room for further improvement. Hayes concluded that Ford's name could become tarnished if the Lotus were to continue winning against only lesser opposition, and that they should agree to use the unit in other teams, and hence potentially dominate Formula One.
At the end of 1967, Copp and Hayes gently explained to Chapman that he would no longer have monopoly use of the DFV and in August 1967 it was announced that the power unit would be available for sale, via Cosworth Engineering, to racing teams throughout the world. Hayes released the DFV initially to French team Matra, headed by Ken Tyrrell with Jackie Stewart as a driver. What followed was a golden age, where teams big or small could buy an engine which was competitive, light, compact, easy to work with and relatively cheap (£7,500 at 1967 pricesHilton, Christopher (2002) Ken Tyrrell – Portrait of a Motor Racing Giant p38 Haynes Publishing or about £90,000 in 2005 money EH.net How much is that worth today? ). The DFV effectively replaced the Coventry Climax as the standard F1 powerplant for the private (mostly British) teams.
, , Matra, , , , , , , , , Wolf and are just some of the teams to have used the DFV. In 1969 and 1973 every World Championship race was won by DFV-powered cars, with the engine taking a total of 155 wins from 262 races between 1967 and 1985.
The advent of ground effect aerodynamics on the F1 scene in 1977 provided a new lease of life for the now decade-old engine. The principle relied on Venturi tunnels on the underside of the car to create low pressure regions and thus additional downforce. Previously, teams running and flat-12 engines had enjoyed a handling advantage due to the low centre of gravity in such a configuration. However, for ground effect, the wide engine was completely the opposite of what was required as the cylinder heads protruded into the area where the Venturi tunnels should have been.
In contrast, the V-configuration of the Cosworth engine angled the cylinders upwards and left ample space under the car for the necessary under-body profileHughes, Mark (2004) The Unofficial Complete Encyclopedia of Formula 1, p. 55, Lorenz Books, which massively increased downforce and gave more efficient aero balance, thus increasing cornering potential and straight line speed. Ground effect British cars and DFV engines effectively killed off the V12/flat 12 engines of Ferrari and Alfa Romeo which many pundits had believed in the mid-1970s would dominate F1 well into the mid-1980s. Drivers Mario Andretti in , Alan Jones in , Nelson Piquet in and Keke Rosberg in used a combination of British ground effect chassis and a DFV engine to claim the Drivers' Championship while DFV-powered cars took the Formula 1 Constructors' World Championship in 1978, 1980 and 1981.
The onset of the turbo era in the early 1980s put an end to the DFV's F1 activities, as even with modifications the 15-year-old engine could not hope to compete with the vast power being put out by the new 1.5-litre turbocharged engines. However, in the early days of turbo F1 cars (1979–1982) the Renault, Ferrari and Toleman were unable to offer consistent opposition to the Cosworth DFV British teams. The early turbo Renault, though powerful (particularly so on high altitude tracks such as Interlagos, Kyalami, Jarama, Dijon-Prenois and the Österreichring) were much heavier, cumbersome, complicated and significantly, much more unreliable than the British Cosworth DFV teams.
The extra power and torque of a turbo engine put much more strain on the gearbox, driveshafts and brakes on the Renaults and Ferraris, and during the early 1980s the sight of a Renault or Ferrari wilting under the strain of its extra power was a common sight. The turbo engine was also hampered by "throttle lag", a delay in throttle response which made the turbo cars very slow on tight, twisty circuits such as Monaco, Long Beach, Zolder, Montreal, Brands Hatch and Detroit, whereas the normally-aspirated Cosworth DFV enjoyed pin-sharp response and accuracy. Also, the light and agile British cars exploited ground-effect technology so well that even on fast tracks such as Buenos Aires, Silverstone, Hockenheim the DFV engine was able to win. For a few years, between 1977 when Renault debuted the powerful but unreliable turbo engine and 1982 when the DFV-powered teams began to negotiate deals for turbo engines of their own, a competitive equilibrium was established.Hughes, Mark (2004) The Unofficial Complete Encyclopedia of Formula 1, p. 62, Lorenz Books, Michele Alboreto took the DFV's last F1 win in a Tyrrell at the in 1983, and Martin Brundle was the last person to race in F1 with a DFV, also in a Tyrrell at the in 1985.
Some Cosworth-using constructors developed their engines in house during a Grand Prix season, such as John Nicholson's Nicholson McLaren operation or Williams F1 using John Judd's workshops to uprate the standard 480 BHP that the DFV was producing in the late 1970s/early 1980s. Uprated pistons, camshafts and valves meant Williams and McLaren's DFVs were producing over 510 BHP at around 11,000 RPM by the early 1980s, which meant the power deficit to the turbocharged Renaults and Ferraris was only around 30–40 BHP in race trim. Since a DFV only needed a 190-litre fuel tank, compared to the 220+ litre sized fuel tank required by a turbo engine, it meant the power to weight ratio of a McLaren MP4 or Williams FW07/08 with their specialist DFV engines were comparable to their turbocharged opponents, albeit with better fuel consumption and much less strain on the rear tyres, gearboxes and rear axle, meaning softer compounds could be used and last longer by both Williams and McLaren, which gave a significant benefit to both grip and tyre durability.
As of mid-1982, 375 engines had been built. The cost of a complete engine at that time, purchased directly from Cosworth, was £27,296, approximately equivalent to £102,000 in 2021.
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==Variants==
===DFY===
With the introduction of turbocharged engines towards the end of the 1970s, Cosworth's naturally aspirated DFV began to lose its predominance. In an attempt to recover some of the performance deficit Cosworth designer Mario Illien reconfigured the cylinder aspect ratio to allow the engine to rev more freely, and combined this with a narrow-angle valve set-up and Nikasil Aluminium liners. The changes upped power output to ~,Robson, G. (2007) Cosworth DFV: Horses for courses. Motor Sport, 83(7), 44–48. and between 11000-12000 RPM but this was not sufficient to keep pace with the turbo cars at most tracks, and it was only through a modicum of luck that Michele Alboreto was able to take what would prove to be the DFV-family's final F1 victory, at the 1983 Detroit Grand Prix. The DFY lived on with back-marker teams until the end of the season, when Cosworth switched their efforts to supporting the new turbocharged Ford GBA V6.
===DFZ===
The announcement at end of the season that turbocharged cars would be banned from , and the introduction of the Jim Clark Cup and Colin Chapman Trophy championships for naturally aspirated cars for , prompted Cosworth to revive their elderly engine design. This resulted in the DFZ, essentially an updated version of the final DFY design. However, the capacity increase for the new 3.5L naturally aspirated formula running alongside the 1.5L turbos in 1987 allowed Cosworth to increase the power output of the unit to . The engine was intended as a temporary measure to tide smaller teams over until the turbos were banned at the end of the season. , , , and chassis were all powered by Cosworth in 1987. Jonathan Palmer of Tyrrell eventually won the drivers' Jim Clark Cup, and his team took the constructors' laurels in the Colin Chapman Trophy. The engine remained in service with minor teams until the end of 1988 and development saw a slight power increase to . The DFZ did not race in Formula One beyond 1988 as the general release of the DFR engine made it obsolete.
The engine did however have a second brief lease of life in sportscar racing, when the FIA announced plans to transition towards using 3.5-L F1-style engines in Group C in the early 1990s. In 1990 Spice Engineering adapted its existing Group C design to take a 3.5L DFZ instead of the previously used 3.3-L DFL engine. However the new engine caused significant problems due to vibration, which resulted in the breakage of components and a significant increase in running costs - Gordon Spice estimated that the DFZ-powered car was about four times more expensive to run than the DFL-engined one. The DFZ was successfully used in FIA Cup class racing in 1992, with that low-powered class being the last appearance of the DFV family in sportscar racing.
===DFR===
From had been operating as the works Ford team, essentially taking over the role from the now defunct Haas Lola team. With the abandonment of turbocharging it was clear that the venerable DFV/Y/Z design was nowhere near being competitive with far newer offerings from and who were building V10 engines for 1989 and beyond, and who were building what they knew, a V12 ( entered F1 in 1989 and like Ferrari, also went down the V12 path). To counter this, drastic changes were made for the DFR of 1988. Although superficially a DFV-design, almost the only feature carried over from previous versions into the DFR was the basic 90° V8 engine architecture. The DFR became available to all customers in 1989, with the Benetton team also using this engine until the 1989 British Grand Prix. The DFR struggled on until the 1991 season finally being eclipsed by the higher revving abilities of new pneumatic valve gear engines such as the HB, and was last used in that year's Australian Grand Prix by the Footwork, Fondmetal, Larrousse and Coloni teams, nearly a quarter of a century after the DFV's first race. By the time of its demise, continued improvement had pushed the DFR power output to nearly , 60% higher than the original 1967 DFV.
The DFR enjoyed success in 1988 with Benetton. The team was the best performed non-turbo team of the season finishing third in the Constructors' Championship behind Ferrari (turbo) and the all-conquering . Thierry Boutsen recorded five podium finishes and Alessandro Nannini scored two podiums. The DFR was also the most powerful non-turbo of the season with a reported . This compared to the 590 of the DFZ and the new Judd V8 with a reported . This still lagged behind the Honda and Ferrari turbos which were producing over each.
==Complete Formula One Results==
See /Results.
==References==
Category:Engines
Category:V8 Engines
Category:Normally Aspirated Engines
Category:Cosworth Engines