Pilbeam spent much of his early life in West London, and had little interest in competition cars until he attended the 1958 British Grand Prix, whilst at Bristol University. In 1959, he constructed a small sportscar with which he competed himself, but without much success. However a later design and an association with club racer Tony Gould brought some success in the class. In 1963, he joined BRM as a stress engineer. He assisted in the construction and design of the P67 whilst still an apprentice and the actual design is usually credited to Tony Rudd. The car, driven by Richard Attwood, was entered for the 1964 British Grand Prix at Brands Hatch but was withdrawn after practice. It did not make any further appearances until 1968, when it appeared in hillclimb events, initially driven by Peter Westbury and subsequently by Peter Lawson and was a championship winning machine. After the abandonment of the P67 project, Pilbeam worked on the BRM H16 engine, helping to develop it to the point where Jim Clark was able to win the 1966 United States Grand Prix with a Lotus 43-BRM.