1928 Bentley 6 ½-Litre

W.O. Bentley unveiled the new 3-litre car bearing his name on Stand 126 at the 1919 Olympia Motor Exhibition. Amazingly, the prototype engine had only fired up for the first time just a few weeks earlier. Bentley's four-cylinder 'fixed head' engine incorporated a single overhead camshaft, four-valves per cylinder and a bore/stroke of 80x149mm. Twin ML magnetos provided the ignition and power was transmitted via a four-speed gearbox with right-hand change. The pressed-steel chassis started off with a wheelbase of 9-feet and 9.5 inches. In 1923, they adopted a dimension of 10-feet and 10-inchs as the 'Standard Long.' The shorter frame was used for the TT Replica and subsequent Speed Model. Rear wheel brakes only were employed up to 1924 when four-wheel Perrot-type brakes were introduced.

The team enjoyed success in the 1922 Isle of Man Tourist Trophy, when Bentleys finished second, fourth, and fifth to take the Team Prize. This led to the introduction of the TT Replica - later known as the Speed Model - on the 9-foot, 9.5-inch wheelbase, short standard chassis.

By the mid-1920s, the 3-Liter was becoming less competitive and its performance was crippled when ladened with heavy coachwork. More was needed. In 1926, Bentley introduced the 6½-Litre, known as the 'Silent Six'.

The Silent Six had been conceived as a touring car to compete with Rolls-Royce's New Phantom. The competition form was known as the Speed Six, and in this guise Barnato/Birkin's Speed Six won the 1929 Le Mans 24 Hour Race ahead of a trio of 4½-Litre Bentleys, and Barnato/Kidston repeated the feat in the following year's Grand Prix d'Endurance at the Sarthe circuit ahead of similarly-mounted Clement/Watney.

Production of the 6.5-Litre Bentley lasted four years, during which time 544 chassis were completed, 182 of these were built to Speed Six specification.

Of the 544 cars built, just 10-percent were delivered with open touring bodies.

by Daniel Vaughan | Nov 2019