BENTLEY CHRONICLE PART1 : #002
BENTLEY CHRONICLE PART1
W.O. Bentley and the Bentley Boy Years #002
A freshly produced 3 Litre from the Cricklewood factory. . 3,048 Bentleys were produced here. As was usual in this period, they were sold as rolling chassis, so they were complete in this condition.
■3,048 Bentleys Built by the Founder over a 10-Year Period
Designed and developed by W.O. Bentley himself, only 3,048 Bentleys were produced in total over a period of just ten years, from 1921 to 1931, and were known as 'W.O. Bentleys' or 'Cricklewood Bentleys', after the location of the factory headquarters. All models produced during this period were guaranteed by the company for five years, which shows how confident W.O. was in the reliability and durability of his automobiles.
The 3 Litre, a memorable debut for Bentley, was a model that clearly reflected W.O.'s intention to place emphasis on the power unit. The 4-cylinder engine was a cross-flow SOHC with four valves per cylinder, incorporating many of the latest aero engine technologies of the time. The number of valves was set at four per cylinder. With a bore/stroke ratio of 80 x 149 mm and a displacement of 2996 cc, in combination with two SU-type carburettors, it produced 65 HP and a top speed of over 80 mph (approx. 128 km/h). In addition, the ignition system was the dual magneto type used in aircraft engines, further enhancing its inherent reliability.
The chassis, on the other hand, was conventionally built and sturdy, probably owing to W.O. 's experience as an apprentice engineer at the Great Northern Railway. Suspension was with semi-elliptical leaf live axles front and rear, which was also standard practice at the time. The rigidity of the robust ladder frame, together with the use of high-quality materials and careful assembly of various parts, meant that the car excelled in road gripping and handling. It also set a high standard in terms of braking power for a model with front-wheel brakes, and became a benchmark for later luxury sports cars. In 1923, a 'Speed Model' was also available, with a higher compression ratio and a larger diameter carburettor to increase power to 80 HP. 3 Litres, especially the Speed Model, competed in races all over Europe, including Le Mans, and became one of the leading British sports cars of the vintage era. Though undeniably expensive at the time of its debut, with a selling price of GBP 1,050 for a rolling chassis, a satisfyingly large number of 3 Litre models (1,622 units), including the Speed model, were produced before being discontinued in 1929.
However, as a luxury automobile, Bentley still had a high demand for more power and smoothness, and in 1926 the '6 1/2 Litre' was launched with a 6-cylinder, 6.6-litre engine. This engine was a 6-cylinder version that retained the basic design of the 3 Litre, with a bore/stroke ratio of 100 x 140 mm, and a total displacement of 6597 cc, producing 140 HP. It is said that the original plan was to keep the 4-cylinder design and increase the displacement, but due to the influence of the R-R Phantom, which had a solid reputation in the luxury car market at the time, the decision was made to go for a 6-cylinder version. At the time of its debut, the 6 1/2 Litre was intended to meet the demands of Bentley customers who demanded heavy, luxurious coachwork that the 3 Litre could not withstand. Bentley, however, was known for an unwillingness to compromise, and soon after the 6 1/2 Litre's debut, a super version, the 'Speed Six', was introduced with larger diameter twin SUs and a compression ratio raised to 5.3:1, producing 180 HP.
The following year, 1927, saw the launch of a new generation 4-cylinder model, the '4 1/2 Litre', with the same in-line 4-cylinder SOHC 16-valve engine as the 3 Litre, but with two cylinders removed from the 6 1/2 Litre's 6.6-litre six-cylinder engine, which had displacement of 4398 cc from a bore/stroke ratio of 100 x 140 mm. Power was stated to be 110 HP. Then, in 1929, the 4 1/2 Litre 'Blower' made its debut. This was a super version of the classic 4 1/2 Litre fitted with a Roots supercharger from Villiers, producing 175-180 HP. Also known as the 'Blower Bentley' among enthusiasts, this model is synonymous with W.O. Bentley. The idea, however, was spearheaded by Henry ‘Tim’ Birkin, a leading member of the Bentley Boys and winner of the 24 Hours of Le Mans. In fact, W.O. himself was not too keen on installing a supercharger. Although it did not achieve its main objective of winning Le Mans, it showed remarkable results in races other than Le Mans, due largely to Bentley Motors chairman Woolf Barnato's Speed Six.
In 1930, Bentley's largest model ever, the 8 Litre, debuted, with a 6 cylinder engine from a 6 1/2 Litre unit with a 110 mm bore, producing 220 HP from a displacement of 7983 cc. The 8 Litre was expected to combine the typical Bentley tourer with a grand sports saloon or limousine, thus attracting a customer segment that Bentley had previously lacked. However, the global recession that followed the Great Depression the previous year had left Bentley in a state from which it could not recover.
This is a revised version of an article that appeared in Flying B No 001 (2008). The information provided here was accurate at the time of publication.
Translation: Mako Ayabe and Michael Balderi
