Page 1 of 1 In 1931 Rolls-Royce purchased Bentley Motors and all its assets, starting a partnership that would last over 70 years. With the sale, the Bentley factory moved from Cricklewood to Derby and the Bentley produced there are commonly referred to as 'Derby-Bentleys.' Introduced in 1933 the first of these 'Derby-Bentleys' was simply referred to as the 3½ Litre and was very similar in design to the Rolls Royce 20/25 launched in the same year.
To comply with Bentley's sporty image, the 3½ Litre was equipped with a slightly more powerful engine. This started a tradition of Bentleys being the more powerful and sportier variant of its Rolls Royce counterpart. Power of the six cylinder engine was increased by the addition of a second Carburetor and a slight increasement of the compression ratio. Compared to the previous Bentley models, the 3½ Litre was quite a step backwards technically.
The similarity in design between the Rolls Royce and Bentley did make things a lot easier for the many coach-builders which were responsible for the custom coachwork fitted on the two chassis. For the bodies fitted on the Bentley chassis, the coach-builders usually penned a slightly more aerodynamic and sportive designs. The coach-builders included Mulliner, James Young and Vandenplas.
In 1936 Rolls Royce launched the 25/30 model, closely followed by the Bentley 4¼ Litre. For the 4¼ Litre the second Carburetor and higher compression ratio was retained. Production lasted until the outbreak of the War, with over 1200 examples produced, more than of any other Bentley model before. The six-cylinder engine was used in various post-War models as well, until it was replaced by a V8 engine. Page 1 of 1