1929 speed six – gu 409
The Bentley Speed Six is one of the marque’s most iconic pre-war vehicles. A high-performance version of the 6½ Litre, the Speed Six became the most successful racing Bentley, winning Le Mans in 1929 and 1930 at the hands of Woolf Barnato, Sir Henry ‘Tim’ Birkin and Glen Kidston.
The 6½ Litre
W.O. Bentley believed that the best way to increase power was to increase capacity, as opposed to Tim Birkin’s faith in supercharging. He therefore developed a new, larger engine to succeed the 4½-litre. With a bore of 100 mm and a stroke of 140 mm, his new straight six had a capacity of almost 6.6 litres. In base form, with a single Smiths five-jet carburettor, twin magnetos and a compression ratio of 4.4:1, the 6½ Litre delivered 147 bhp at 3500 rpm. 362 examples were built at Bentley’s factory in Cricklewood, north London, on a variety of chassis of different lengths depending on the body style requirements of individual customers.
The Speed Six
The Speed Six chassis was introduced in 1928 as a more sporting version of the Bentley 6½ Litre. The engine was modified to liberate more power, with twin SU carburettors, a higher compression ratio and a high-performance camshaft. The Speed Six chassis was available to customers with wheelbases of 138 inches (3,505 mm), 140.5 inches (3,569 mm), and 152.5 inches (3,874 mm), with the short chassis being the most popular. 182 Speed Six models were built between 1928 and 1930.
The racing version of the Speed Six had a wheelbase of 11 feet (132 in; 3,353 mm) and a further-developed engine running a compression ratio of 6.1:1 and developing 200 bhp. Two wins at Le Mans in 1929 and 1930 cemented the Speed Six’s place in Bentley history.
In March 1930, Barnato raced against the Blue Train in a Speed Six with H. J. Mulliner saloon coachwork, reaching his club in London before the train was due in the station at Calais. It had generally been believed that the car in the race was a Gurney Nutting Sportsman Coupé, but that coupé was delivered to Barnato in May 1930, more than a month after the race.
The Speed Six joined the Heritage Collection in 2021, completing Bentley’s roster of pre-war models. It was originally built for a W.F. Watson and fitted with a Weymann saloon body by Victor Broom, and was delivered in September 1929. The car was fully restored in 2005, at which point it was converted to Team Car specification, matching the Speed Sixes that raced at Le Mans. The car is finished in British Racing Green with a black interior and is excellent condition.
|Date Produced||August 1929|
|Chassis/Engine No.||KR2682 / KR2679|
|Body||Le Mans Team Car Tourer on short chassis|
|Engine||6597 cc 6-cylinder in-line monobloc in cast iron. 5.3:1 compression ratio. Overhead camshaft, four valves per cylinder and twin magnetos|
|Power||180 bhp @ 3,500 rpm|
|Transmission||4-speed, non-synchromesh D-Type gearbox|
|Chassis||138 inches (3,505 mm) short chassis|
|Performance||Maximum speed 119 mph|