Obituary: Keith Duckworth

Keith Duckworth, who has died at the age of 72, was widely acclaimed in formula one motor racing circles as one of the most imaginative and resourceful engineers of the postwar era. His Cosworth DFV grand prix engine changed the sport's landscape for ever after its introduction at the 1967 Dutch grand prix, where it powered Jim Clark's epochal Lotus 49 to a dominant debut victory.

The availability of an off-the-shelf formula one engine that was ruggedly dependable and easy to operate opened up the possibility of competing in the world championship for a whole raft of new independent teams. Between Clark's win in Holland and Michele Alboreto's victory in the 1983 Detroit grand prix, the Cosworth DFV and its derivatives won no fewer than 155 world championship rounds.

A sometimes bluff and always direct Lancastrian, Duckworth's path to motor racing fame started when he left Lotus in 1958 to start his own race engine development company, in partnership with Mike Costin, a fellow former Lotus engineer. The name Cosworth Engineering sprang logically to mind and thus the seeds of what was to become a hugely successful enterprise were sown.

Duckworth was born in Blackburn. His father Frank owned a weaving business and sold cotton on the Manchester Cotton Exchange. The family were comfortably off, but their relative affluence was the product of much hard work and application, qualities their son would consistently demonstrate as he carved his own niche in his chosen business.

Educated at Giggleswick school, north Yorkshire, Duckworth later did national service with the RAF, although his aspiration to become a military pilot received a severe dent within hours of his being awarded his wings. He actually dozed off in the cockpit, and was ejected from the course for "dangerous and incompetent night flying". Later in life he became an accomplished and meticulous helicopter pilot, only relinquishing his licence after a heart attack in 1973.

Cosworth fortunes really took off at the start of the 1960s, when the firm began building Ford Anglia-based engines for the new 1100cc formula junior, from which point the name Cosworth increasingly became synonymous with light, efficient and reliable racing engines.

The company had started in distinctly down-at-heel premises in Friern Barnet, north London, before moving to Edmonton in 1961, and finally to what became its spiritual home in St James Mill Road, Northampton, at the end of 1964. Duckworth's big break as an engineer came in 1965 when Colin Chapman, the Lotus founder, persuaded Ford to finance the design and manufacture of a new engine for the 3-litre formula one, which was due to start in 1966.

Thanks to the shrewd and perceptive influence of Walter Hayes, head of Ford's public affairs department, Lotus, Ford and Cosworth were all brought together. Hayes successfully sold the idea to Patrick Henessey, the Ford of Britain chairman, and approval duly followed from Ford's world headquarters in Detroit. Cosworth was thus commissioned to design, develop and build the 3-litre V8 formula one engine, and the four-cylinder FVA formula two engine, for a fee of £100,000. Thirty years later, Ford veterans still describe it as "the bargain of the age".

Duckworth set up his drawing board in the quiet of his home, away from the Cosworth factory, and settled down to his design work. The project took just under two years from his putting pen to paper to the first Cosworth DFV being handed over to Team Lotus in April 1967. He frequently worked 16-hour days during the initial nine-month design period, during which he lost 40lbs in weight. Although modestly self-effacing about the effort he expended, Duckworth was undeniably proud of the end result.

Prompted by his heart attack - and the possible death duty implications of his 85% stake in the company - Duckworth sold Cosworth in 1980 to United Engineering Industries, a Manchester-based engineering firm. But he continued working as hard as ever, to the eventual further detriment of his health, and had to undergo open heart surgery in 1987, soon after which he relinquished the role of company chairman to Mike Costin.

He is survived by his second wife wife, Gill, and his two children Roger and Tricia.

· David Keith Duckworth, motor racing engineer, born August 10 1933; died December 18 2005