1930 Bentley 4.5 Liter Supercharged

Walter Owen (W.O.) Bentley was the youngest of nine children and the son of a prosperous family that could afford to have him privately educated at Clifton College in Bristol. At the age of 16, he began a premium five-year apprenticeship working as an engineer with the Great Northern Railway at Doncaster in Yorkshire. This gave him practical experience with complex railway machinery including the casting and manufacturing of many components. When his apprenticeship ended in the summer of 1910, he decided to forsake the railroad and seek employment elsewhere.

Joined by his brother, H. M. (Horace Millner), the duo formed a company in 1912 called 'Bentley and Bentley' with the purpose of selling French DFP cars. Unimpressed with the DFPs performance, W.O. added lightweight aluminum alloy pistons and a modified camshaft, resulting in a car that captured several records at Brooklands in 1913 and 1914.

With the onset of World War I, W.O. applied the use of aluminum alloy pistons to military applications, increasing the output of the engines, as well as allowing higher compression ratios and engine speeds, while operating at cooler temperatures. His contributions earned him the MBE award (Most Excellent Order of the British Empire).

Bentley Motors

On Stand 126 at the 1919 Olympia Motor Exhibition, W.O. Bentley debuted a new 3-liter car equipped with a prototype engine that had fired up for the first time just a few weeks earlier. Bentley Motors Limited was founded in humble premises located in New Street Mews, Baker Street, London. W.O. was joined by Frank Burgess (formerly of Humber) and Harry Varley (formerly of Vauxhall Motors), along with engineer Clive Gallop. The first complete Bentley 3 Litre car was road tested in January of 1920 and the first production version was delivered in September of 1921. The 3 Litre model would form the foundation for the company's prestigious legacy in motor racing competition. Its iconic radiator, leather-strapped bonnet, and British Racing Green livery would become the archetypal vintage sports car.

Among the early motorsport accolades were a second, fourth and fifth place finish at the 1922 Isle of Man Tourist Trophy, earning Bentley the Team Prize. This accomplishment birthed the TT Replica, which later became known as the Speed Model. The Bentleys competed in hill climbs and at Brooklands, and a single 3 Litre raced at the Indianapolis 500 mile race in 1922 driven by Douglas Hawkes to a thirteenth place finish. Jean Chassagne won the 1921 Grand Prix Sunbeam, and he would later become part of the famed 'Bentley Boys,' a group that would include Woolf Barnato, Jack Dunfee, Tim Birkin and Sammy Davis. The team's inaugural outing at Le Mans was in 1923 when Duff and Frank Clement's private entry took fourth place. The following year, a 3 Litre won Le Mans and subsequent models won again in 1927, 1928, 1929, and 1930.

Production of the 3-Liter Bentley lasted from 1921 through 1929 with 1,622 examples built.

The Bentley 4½ Litre

As the competitiveness of the 3 Litre began to diminish, coupled with the heavy and voluptuous coachwork being applied to many road-going chassis, Bentley introduced the 4½ Litre model.

Before the four-cylinder, 4½ Litre model, Bentley had created the 6½ Litre model. A prototype was created in 1925 with an experimental six-cylinder engine of 4½ litre capacity. A rumor exists that states that while the car was being tested in France, its driver encountered Rolls-Royce's 'New Phantom' undergoing similar trials. Naturally, something of a race is said to have ensued, the outcome of which immediately led Bentley to increase the capacity of its embryonic engine to no less than 6½ litres. Produced from 1926 to 1930, the 6½ Litre model later spawned the immortal Speed Six, which is said to have been W.O.'s favorite among all the illustrious motorcars he created.

The 6½ Litre model was expensive, with a larger chassis than the 3 Litre, a more potent engine, and was suitable for the large, heaving limousine bodies that many customers preferred.

The new 4½ liter model was in essence two-thirds of the six-cylinder 6½-liter unit. It effectively employed the chassis, transmission and brakes of the 3 liter, with its four-cylinder motor retaining the six's 100x140mm bore/stroke plus the company's familiar four-valves-per-cylinder fixed-head architecture, but with the front-end vertical camshaft drive of the 3-liter. Most engines used two valves per cylinder, but the Bentley engine had four valves per cylinder actuated by a single overhead camshaft. With two SU carburetors and dual ignition with Bosch magnetos, the road-going versions developed 110 horsepower while the uprated racing versions produced 130 bhp.

The chassis was formed from steel and reinforced with ties. The brakes were conventional with 17-inch drums operated by rod and finned for cooling. The four-speed gearbox was unsynchronized and the suspension was comprised of semi-elliptic leaf springs.

Production of the 4½-Litre lasted for four years, and all but ten of the 667 cars were built on the 3-Litre's 'Long Standard', 10-foot 10-inch-wheelbase chassis. The length measured 172.4 inches and the width of 68.5-inches. The shorter platform had a wheelbase of 117.5-inches. Like other Bentley models of the period, buyers were able to specify their preferences from a range of mechanical and electrical equipment, in addition to their preferred coachbuilder and body style. In racing guise, a properly prepared 4½-Litre was capable of 120 mph.

The first Bentley Team car to race with the 4.5-liter engine was 'Old Mother Gun,' essentially a three-liter team car fitted with a new cylinder block. During the 1927 Le Man's race, the new 4.5-liter engine proved fast until the historic Maison Blanche crash. The infamous White House crash involved eight cars including all three of the Bentley team entries and caused the retirement of two of them. The third Bentley, albeit badly damaged, managed to win the race. It was a 3 Litre Speed model driven by Dudley Benjafield and Sammy Davis. Later that same month, Old Mother Gun was run at the Grand Prix de Paris, which it easily won. This was the first victory for the new 4 1/2-litre engine.

For the 1928 racing season, Bentley worked on preparing new works cars based on the 4 1/2-litre production chassis in addition to Old Mother Gun. The first two examples built were YV 7263 and YW 2557, and wore lightweight Le Mans coachwork created by Vanden Plas. The specialized production chassis consisted of an ash frame with fabric covering, complete with a rear D-shaped fuel tank mounted with a vertical spare. Covered with a rounded aluminum shroud, the resultant appearance earned the cars their 'Bobtail nickname.

During the 1928 24 Hours of Le Man's race, YW 2557 suffered a broken frame and Old Mother Gun suffered a similar fate, breaking its frame shy of the finish, yet Barnato was able to limp it to victory. The car driven by Birkin finished 5th overall. On the return trip from Le Mans, the third 4 1/2 Litre broke its frame. Upon return to Cricklewood, each of the team cars received new frames with significant chassis strengthening.

The 4½ liter Blower Bentley

The 4.5 litre Blower Bentley originated from the vision of Sir Henry Birkin, whose goal was to increase the performance of the 4½ Litre model and to convince then-company Chairman Woolf Barnato of its potential. Barnato seemingly agreed, despite W.O. Bentley's early objection to the supercharged concept.

The concept was simple; attach a Roots-type supercharger to the 4.5-liter engine. The work was performed by engineer Amherst Villiers, who had also produced the supercharger. Since W.O. refused to allow the engine to be modified to accommodate the supercharger, the unit was placed at the end of the crankshaft, in front of the radiator. Employing a unique lubrication system, along with special pistons and crankshaft, the engine produced 175 bhp at 3,500 for the touring model and 240 hp at 4,200 rpm in racing guise.

To comply with the homologation restrictions of Le Mans, the factory was required to build fifty examples. The inaugural competitive outing for the 'Blower' Bentley was in June of 1929; July brought the first podium finish. Satisfied with its potential, production of the supercharged cars began that June with the intent of displaying two production 'Blowers' on the stand at the 1929 Olympia Motor Show. Customers began receiving the production Blowers by 1930. The first 25 supercharged cars received chassis numbers beginning with SM; these had smooth-cased 'blowers.' The subsequent 25 chassis numbers, beginning with MS, had ribbed blowers to aid cooling.

Having satisfied the Automobile Club de l'Ouest requirements to compete at Le Mans, the Blower Bentley were able to 'toe' the line in 1930. While powerful, the Blower Bentleys were less reliable than its naturally aspirated siblings. The two Blower models entered in the 1930 24 Hours of Le Mans by Dorothy Paget, one of which was co-driven by Tim Birkin, did not complete the race. Birkin placed second in the French Grand Prix at the Circuit de Pau in 1930.

When the Blower Bentley was able to finish the race, the result was often monumental. Mildred Bruce, a British female racer, achieved a 24-hour distance record at Montlhéry in a Blower Bentley, with an average speed of 89.5 mph.

Production

Production of the 4½ Litre Bentley ended in November of 1931 with 720 examples built, including 50 supercharged examples.

by Dan Vaughan

Tourer

The addition of a supercharger, clearly seen on the front of this car, added even greater power to the already strong 4.5-liter model. Their racing record was spotty, but a lightened version of this chassis was the fastest of all the great vintage Bentley marque.

by Simeone Museum

LeMans Sports by Vanden Plas
Chassis number: 3918

This car is one of the original 50 supercharged 4.5-Litre 'Blower' Bentleys. It is also one of just three Blowers built by Tim Birkin to LeMans specifications, with extended bonnet, external LeMans fuel tank, and team car instrument panel. The car was built for Billy Fiske, the Cresta Run Bob-sleigh Champion. Fiske was also the first American to join the British RAF in 1939 and he tragically lost his life flying a Hurricane during the Battle of Britain. While in his possession, this car lapped Brooklands' outer circuit at 121.4 mph. After Fiske, the car was in single ownership for 50 years before changing hands. It has recently undergone a complete restoration by Bentley expert Graham Moss, who reunited the car with its original engine and finished the body in the period-correct Rexine fabric.

Open Sports Tourer by Vanden Plas
Chassis number: SM3913
Engine number: SM3916

W.O. Bentley showed the first factory-built Supercharged Bentley 4.5 Litre at the London Olympia Motor Show in the autumn of 1929. The first 25 supercharged cars received chassis numbers beginning with SM; these had smooth-cased 'blowers.' The next 25 chassis numbers, beginning with MS, had ribbed blowers to aid cooling. This car still has its original supercharger cover, designed to keep the outside carburetors warm and prevent icing up in cold weather. This motor car is considered by many people in the Bentley community to be the most original of the 50 supercharged 4.5 Litres produced by the factory. Its original Rexine-covered body shows the original blue paintwork that was uncovered during its recent conservation. It was first sold to Mr. G. B. Sanderson, fitted with rare Bosch headlamps and a larger-than-standard 25-gallon fuel tank. In 1948 it passed to noted collector Raymond Erith, who summarized the car as 'quite the nicest car' he had ever owned. Dick Stitt of Chicago took ownership in 1955 and maintained its originality for the next 33 years. Its current owner acquired the car in 2011. 2019 was the first time it had been shown at the Pebble Beach Concours d'Elegance.

Drophead Coupe by Gurney Nutting
Chassis number: SM3909
Engine number: SM3910

This 4.5 Litre Supercharged Bentley, with drophead coupe coachwork by Gurney Nutting, was built for Bentley Motors Chairman Woolf Barnato. Barnato was part of the social set of wealthy British motorists known as the 'Bentley Boys'; his fortune came from his family's diamond and gold mining interests. He acquired his first Bentley in 1925 and a year later agreed to finance W.O. Bentley's entire company. Winning at Le Mans three time and in numerous races at Brooklands made him a significant personality at Bentley Motors, and he was directly responsible for persuading W.O. to build the supercharged cars.

The design of this drophead coupe body is typical of Barnato's taste for extravagant sporty motorcars. With its boattail back end and flowing fenders it would have looked rather stunning sitting next to his other Gurney Nutting bodied car, the famous 'Blue Train' Bentley Speed Six.

Open Sports Tourer by Vanden Plas
Chassis number: SM3913
Engine number: SM3916

This Bentley 4 1/2 Litre Supercharged 'Blower' Sports Tourer was built in 1930. It received the standard 10-foot, 10-inch frame, a D-type gearbox, 15/46 rear axle, and engine no. SM3916 with a smooth case Amherst Villiers Mk IV supercharger, no. 113. The 4,398cc SOHC inline four-cylinder engine breathed through twin SU HVG5 carburetors and with the help of the Amherst Villiers Roots-Type Supercharger, produced 182 horsepower at 3,900 RPM. It was paired with a four-speed non-synchromesh D Type gearbox and four-wheel mechanical drum brakes to provide the stopping power. At the front was a beam axle while the rear used a live axle, with semi-elliptical leaf springs all round.

After completion of the chassis, SM3913 was sent to Vanden Plas in Kingsbury, UK, where it received its four-seater, fabric-covered Sports coachwork (body number 1662), with full-length wings, a hinged single-pane windscreen, and a rear-mounted spare tire. It wore a blue livery with matching blue leather upholstery and black wings.

On July 17, 1930, the Bentley was registered as 'GH1932' and delivered to its first owner, Gerard Bristowe Sanderson of Edinburgh, Scotland. In his care for a short period of time, it was sold in January of 1933 to R.G. Wilson of East Sheen, London. Later that same year, it was advertised for sale by Jack Olding and sold to another London resident, A.C. Sewall. While in his care, Mr. Sewall had Bentley service the 35,000-mile Blower, including replacing the original Smith headlamps for Bosch units, along with a general chassis overhaul, radiator repair, and Autopulse reconditioning.

The car was sold in 1936 and shortly thereafter, it was fitted with a larger 25-gallon semi-Le Mans fuel tank.

The Bentley was placed in storage for many years, and when it emerged, it was acquired by Harry Kemp-Place of Essex. He sold the Bentley in 1948 to Raymond Erith who used it regularly as his daily driver.

The Bentley left its native Britain for the first time, in 1955, when it was sold to Richard E. Stitt of Hinsdale, Illinois. It remained in Mr. Stitt's care for over three decades and was shown occasionally at local meets. Tim Scott purchased the Blower from Mt. Stitt in 1988 and had it returned to England where it was displayed at the BDC Kensington Gardens Concours that June. The Bentley remained in Mr. Scott's ownership until 2004, when it was sold to Don Williams' Blackhawk Collection in Danville, California. It would later return to England when it was sympathetically restored by Rolls-Royce and Bentley specialist P & A Wood.

In 2011, the car was purchased by a European-based collector. After driving the Blower for several years, including entering it in the Flying Scotsman Rally in 2014, he commissioned R.C. Moss to restore the car in such a way as to maintain its originality, but return it to factory-delivered standards. The work was performed between 2014 and 2019 and upon completion, made its restoration debut at the 2019 Pebble Beach Concours d'Elegance, where Bentley was the featured marque. It was awarded a First in Class from a field of significant 4 1/2 Litres.

by Dan Vaughan

The Bentley 4 1/2 liter came into existence to fill a void left by the 3-liter and the 6.5-liter variants. The 3-liter suffered from underperformance while the 6.5-liter was unsafe for the roads. The 6.5-liter was powerful, and with poor road-conditions often caused tires to fail quickly. The solution was the Bentley 4.5-liter; a vehicle that had enough power to carry the vehicle down the road at a good pace. The chassis consists of channel-steel, front and rear suspension by semi-elliptic leaf springs, and 4-wheel drum brakes.

Production amounted to a total of 733 cars of all body styles. Fifty-four cars were equipped with the famous supercharged engine, 'Blower Bentleys,' built by the race driver Sir Henry 'Tim' Birkin as a private venture - against W.O. Bentley's wishes.

The 4.5-Liter Supercharged Bentley, better known as the 'Blower' Bentleys, is a sporting automotive icon that earned its place in history as an engineering marvel and powerhouse. Only 50 examples, plus an additional five racing prototypes, were created. In the modern era, they are among the top rank in collector cars throughout the world.

Engineer and founder W.O. Bentley was hesitant to adapt a supercharger to his 4.5-liter engines. Rather, the development was financed by a woman, the Honorable Dorthy Paget, who provided the funds necessary to complete the project. It was for Henry R.S. 'Tim' Birkin, one of the 'Bentley Boys' who campaigned the Bentleys at many venues and various competition events bringing recognition and victories to the Bentley marque. The list includes Brooklands with its closed oval course, and the other extreme, LeMans, with his challenging road course.

Birkin had intended to race the supercharged 4.5-liter Bentley at LeMans in 1929, but lubrication problems on the early cars halted those plans. Instead, Woolf Barnato (Bentley's chairman and fellow factory team racer), Birkin, and Glen Kidston drove the Bentley Speed Six Models in 1929 to victories at LeMans.

Birkin was able to convince Barnato to enter the 'blower' Bentley in the 1930 LeMans race. In order to do so, homologation requirements had to be satisfied. The rules stated a minimum of 50 examples had to be built. Bentley officially introduced their production versions of the cars at the 1929 Olympia Motor Show, with the fist cars on sale in April of 1930.

With homologation requirements satisfied, Bentley entered two blowers and three Speed Six models. Birkin's LeMans blower was co-drive by Jean Chassagne. The Blower Bentley showed great promise early in the race, and by the fourth lap had passed a highly-competitive supercharged Mercedes at 126 mph. In the process it shredded a tire and was forced to stop. At the time, they had been averaging 89.66 mph per lap, which was a new lap record for the course.

The other Bentley's were given the job of chasing down the Mercedes. Their job became much easier when the Mercedes was forced to retire when their battery died. The Blower Bentley's would endure similar fate, as they were forced to retire in the 20th hour. The Speed Six models went on to secure a 1-2 Bentley victory.

1930 was the last year the Bentley factory team would compete at LeMans, as the company had fallen on very difficult economical times. Dorothy Paget eventually withdrew her support for the Birkin blowers as the cost to compete continued to escalate. This brought an end to the short-lived saga of the Bentley blower era.

It is believed that 43 examples of the blower Bentleys are still in existence.

by Dan Vaughan