The FPF was a double overhead cam all aluminium four cylinder that was essentially half of the FPE V8 engine, which was designed as a pure racing engine from the outset. Designed in 1955 and becoming available in 1956, it had gear-driven camshafts, steel alloy cylinder sleeves and individual oil scavenge as well as pressure feed pumps for a dry sump system. Carburetion was by two twin-choke Weber DCO side-draft carburettors.
It started life as a 1,475 cc Formula Two engine by enlarging the 2.95" bore of the FPE to 3.2" with the slightly increased 2.8" stroke, and was gradually enlarged for use in Formula One. See the above Design section for its unusual intake port design.
A 1,964 cc (3.4" x 3.3") version took Stirling Moss and Maurice Trintignant to Cooper's first two Grand Prix victories against 2.5 L opposition in 1958. After the interim 2,207 cc (3.5" x 3.5") version, a larger block was cast to result in 2,467 cc (3.7" x 3.5") in 1958, and then to a full-sized 2,497 cc (3.7" x 90 mm) in 1960. Jack Brabham won the World Championship of Drivers in both 1959 and 1960 driving FPF powered Coopers.
The FPF with larger block (to accommodate larger bores) was then adapted to the new 1.5-litre Formula One of 1961 as 1,499.8 cc (82mm x 71mm) FPF Mk.II and won three World Championship Grand Prix races in that year. In addition, capacity was increased to 2,751 cc (96mm x 95mm) for the Indianapolis 500 and this larger variant was also utilised for sports car racing, the Intercontinental Formula and Formula Libre racing. It also served as a stopgap in the new 3.0 L Formula One regulation, which went into effect for 1966. The old 2,497 cc FPF gained a new lease of life in 1964 with the introduction of the Tasman Formula and the Australian National Formula, both of which had a maximum engine capacity of 2.5 litres.
The following is the list of FPF versions:
1956 FPF 1475cc 4 cyl 3.20 x 2.80" 141 bhp (105 kW)@7300rpm for F2
1957 FPF 1964cc 4 cyl 3.40 x 3.30" 175 bhp (130 kW)@6500rpm for F1
1958 FPF 2207cc 4 cyl 3.50 x 3.50" Smaller block
1958 FPF 2467cc 4 cyl 3.70 x 3.50" 220 bhp (160 kW)@6500rpm Larger block for F1
1960 FPF 2497cc 4 cyl 3.70" x 90mm 239 bhp (180 kW)@6750rpm. for F1
1961 FPF 2751cc 4 cyl 96mm x 95mm Indianapolis and Formula Libre
1961 FPF Mk.II 1499.8cc 4 cyl 82mm x 71mm 151 bhp (113 kW)@7500rpm for F1