1931 Bentley 4 1/2 Litre


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After a brutal but heroic 8th Place in the 1928 German Grand Prix, Sir Henry “Tim” Birkin was convinced that the Bentley 4 1/2 Litre could be substantially more competitive through supercharging. There was a notion afoot that supercharging was the key to success, as Alfa Romeo, Bugatti, and Mercedes- Benz were all contenders in international events with blown powerplants.

W.O. Bentley, on the other hand, was firmly against the supercharging of his cars. The Bentley racing strategy was based on endurance and reliability, all too often pushing hard at the onset of a race and forcing the supercharged competitors to break; easy victory ensued. W.O. remained confident in the awe-inspiring Speed Six with its normally aspirated 6 1/2-litre engine.

In order to make a supercharged Bentley 4 1/2 Litre a reality, Birkin would have to find outside help. For the supercharger itself, Birkin turned to Amherst Villiers who found fame with the Vauxhall Villiers Special. Birkin, who had set up his own racing shop, entered an agreement with Bentley Motors and Amherst Villiers. It is also important to note that Birkin had the support of Woolf Barnato, who then controlled much of Bentley’s activities. In order to run at Le Mans, the supercharged 4 1/2 Litre would have to be a standard production model. W.O. apprehensively obliged.

The design of the supercharger was left to Villiers, but the parameters had been set; the blower was to be driven off the crankshaft and therefore mounted in front of the engine. Immediate deficiencies were noted and the subsequent development of the “heavy crank” 4 1/2-litre block ensued. Eventually the design was completed and tested. Although Birkin failed to compete in 1929 at the 24 Hours of Le Mans with the two intended supercharged cars, June saw the first ever competitive outing for a “Blower” Bentley and July brought the first podium finish.

Production of the supercharged car was agreed to that June and a push was made to have two production “Blowers” on the stand at the 1929 Olympia Motor Show. By 1930, production blowers were being delivered to enthusiastic new customers. A total of 50 production cars were built over the two-year period, and with that Birkin had met the Automobile Club de l’Ouest requirements to compete at Le Mans.

This car, chassis MS3928, was fitted with engine no. SM3921 and delivered new via Jack Olding & Co. Ltd. to Mr. W.C. Gordon Black of Fife, Scotland, who acquired it in early 1931, and maintained ownership through 1933, already accumulating an impressive 35,000 miles. A copy of MS3928’s early service record that accompanies the car, indicates various services carried out through 1938, including engine decarbonization, clutch relining, supercharger service, and suspension alignment. A photograph of the “Blower,” taken by London dealer Rowland Smith in 1934, depicts its striking original 2/4 place drophead coupe body by J. Gurney Nutting, as fitted with helmet-style fenders and its aluminum supercharger cowling.

Bentley expert and historian Clare Hay’s records list a number of brief UK-based caretakers of MS3928, beginning in 1940. Among the owners is Squadron Leader W. Kent, of Hampshire, UK, who purchased the Bentley in 1952. In a charming and illuminating 1993 letter he sent to Ms. Hay, he fondly recalled his time with the Blower, which he described as having ideal coachwork with two comfortable seats up front and two occasional folding seats to the rear. He mentions that he was at the time an impecunious young officer, stationed overseas, who could neither afford to bring the car with him on deployment nor pay for its storage. He had a sense that the Bentley would someday be valuable to collectors, and that it was a “terrible wrench” to be forced to part with it.

The squadron leader had been correct, as his Blower was later sought out and purchased by collector Charles R.J. Noble of Connecticut, in 1961. Mr. Noble imported MS3928 to the US as a rolling chassis in 1966, adding it to the other Blowers in his collection. Now without its coachwork, plans were made to ship the chassis back to the UK to receive a Birkin team Le Mans-replica body and fittings. The kickplate in the front doorjamb, dated 1970, records the coachbuilder as Restor Works of Swadlincote, UK. Birkin team features included lightweight fabric four-seat coachwork, aeroscreens, cycle-style fenders, mesh stone guards, large capacity Le Mans fuel tank, leather hood straps, racing dashboard with correct, large instruments, and a cord-wrapped steering wheel. Following completion of the coachwork and assembly, MS3928 was then reimported to the US where it was toured, shown, and enjoyed by the Noble family for a further 38 years. During their later tenure with the car, the engine was rebuilt utilizing new sump and block castings, with a new alloy crankcase stamped with the blower’s original engine number, SM3921. This crankcase was machined to receive modern shell bearings in favor of the original, and rather temporary white metal bearings. Phoenix Crankshafts Ltd. of Slough, UK supplied the heavy-duty crankshaft, which powers the original Amherst Villiers ribbed-case blower unit, no. 130.

In 2008, the Blower Bentley was acquired by the consignor who has since displayed it among his world-class collection of veteran and vintage competition cars. It has been looked after by a professional, fulltime staff, and has received regular spirited exercise and maintenance as necessary. Closer inspection reveals MS3928’s stampings on the front cross member of the frame and the nearside dumb-iron knuckle. MS3928 can also be seen clearly stamped on both the front and rear axles as well as the steering box. Also of note is the accompanying original instruction book, inscribed with the blower’s chassis number.

Today, MS3928 stands as one of the most important vintage Bentleys, bodied in homage to the courageous Bentley Boys and their heroic efforts at Le Mans. It displays an appropriate patina, with the green paint, roundels, and Union Jack texturized by the coachwork’s fabric. Inside, the lighter green leather has mellowed with age and is trimmed in the vintage style with leather-covered lead beading nailed appropriately in place. The engine-turned dash is fitted with an intoxicating array of gauges, switches, and controls in the style of the original team cars.

An original Blower Bentley is unparalleled in both status and stature, and MS3928 is an ideal choice for participation in the world’s finest events including the legendary Bentley Drivers Club rallies, the Mille Miglia, the Colorado Grand, and other spirited drives throughout the world, with every mile steeped in the spirit of competition and the quest for victory.

*Please note that the VIN listed on the title for this vehicle contains a typographical error; the second character of the VIN is listed as a “5”, but is in fact a “S”.