Bentley 6½ Litre / Speed Six (1926–1930)

De Bentley 6½ Litre and the powerful Bentley Speed ​​Six were rolling chassis that were produced by Bentley from 1926 to 1930. The Speed ​​Six, introduced in 1928, became the most successful racing Bentley.

1926 Bentley Speed ​​Six

History and background

The Bentley 6½ Litre and the high-performance Bentley Speed ​​Six were rolling chassis produced by Bentley from 1926 to 1930. The Speed ​​Six, introduced in 1928, became the most successful racing Bentley.

The 6½ Litre was of a very different character from the 3-litre, and well suited for elegant enclosed bodywork. It was joined in 1928 by the Speed ​​Six version, which derived its extra performance from twin carburetors and a higher compression ratio. In the steady hands of Woolf Barnato, Bentley's principal financial backer, Speed ​​Sixes won at Le Mans in 1929 and 1930.

WO Bentley combined one of his road tests of the Sun with a trip to the 1924 French Grand Prix in Lyon. On his return journey to the ferry at Dieppe, he encountered another camouflaged car at a three-way intersection. WO and the Rolls-Royce test driver recognized each other and began racing each other along the national roads. This street race lasted until the Rolls-Royce driver's hat blew off and he had to stop to retrieve it. Realizing from the unprepared race that the Sun had no performance advantage over Rolls-Royce's latest development, WO increased the bore of his six-cylinder engine from 80 to 100 millimeters.

A street race with a Rolls-Royce test driver as inspiration for the greatest Bentley of the 1920s — automotive history sometimes writes itself best.

Interior of a 1926 Bentley Speed ​​Six

Design and interior

During that period, the 6,5 Litre was known as the “Big Six”. The engine was a development of Bentley’s three-liter power unit. First shown at the London Motor Show of 1925, these cars were with customers in March 1926.

The standard 6½ Litre had a stroke of 140 mm and a bore of 100 mm, giving the six-cylinder unit a displacement of 6,6 liters. It had four valves per cylinder, an overhead camshaft, and a one-piece engine block and cylinder head cast in iron.

A wide variety of wheelbases were produced — from 132 to 152,5 inches (3.353 to 3.874 mm). The most popular wheelbase was 150 inches. Every 6½ Litre was therefore effectively a bespoke car — the wheelbase, bodywork, and finish entirely according to the buyer's wishes.

Model variants

Standard 6½ Litre (1926–1930) — the deluxe tourer:

362 were the 'Standard' 6½ Litre. Single carburetor, compression ratio 4,4:1, 147 hp. Aimed at luxury coachwork and comfortable touring — the car for the Bentley Boys who brought Le Mans to the battle but wanted to drive in style at home.

Speed ​​Six (1928–1930) — the racing legend:

The Bentley Speed ​​Six was introduced in 1928 as a sportier version of the Bentley 6½ Litre. With a single-port block, two SU carburetors, a high-performance camshaft, and a compression ratio of 5,3:1, the Speed ​​Six's engine produced 180 hp at 3.500 rpm. 182 were built to Speed ​​Six specification.

Blue Train Bentleys — the most famous Speed ​​Sixes:

Two Bentley Speed ​​Sixes became known as the Blue Train Bentleys following the involvement of their owner, Woolf Barnato, in the Blue Train Races of 1930. The most famous Bentley street race of all time — Barnato challenged the Blue Train from Cannes to Calais and won by four minutes.

The 6½ Litre produced 147 hp at 3.500 rpm. The Speed ​​Six produced 180 hp — more power than the Blower Bentley 4½ Litre in standard configuration.

Competitors

The 6½ Litre and Speed ​​Six competed in the absolute top segment of the late 1920s. Direct competitors were:

• Rolls-Royce Phantom I / II (direct competitor — the reason for the street race)
• Mercedes-Benz SSK / SSKL
• Bugatti Type 41 Royale
• Hispano-Suiza H6

Successor model

Then, in 1931, came WO's true supercar, the 8-liter. Enormous, strikingly beautiful, fabulously expensive, and capable of 100 mph in every version, it is one of the immortals of motorsport. The 8 Liter was the direct successor to the Speed ​​Six as the flagship — but its timing was catastrophic. Introduced in the year of the stock market crash, it survived only one year before Rolls-Royce acquired Bentley.