Bentley 4 1/4 DB Series M Coupe by Park Ward
Car producer :  |
Bentley |
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Model: |
4 1/4 DB Series M Coupe by Park Ward |
Year: |
1936-1939 |
Type: |
Coupe |
The Bentley 4½ Litre was a British car based on a rolling chassis built by Bentley Motors. Walter Owen Bentley replaced the Bentley 3 Litre with a more powerful car by increasing its engine displacement to 4.4 L (270 cu in).
Bentley buyers used their cars for personal transport and arranged for their new chassis to be fitted with various body styles, mostly saloons or tourers. However, the publicity brought by their competition programme was invaluable for marketing Bentley's cars.
Like Rolls-Royce, all Bentleys were bodied by independent coachbuilders. Each operational chassis was fitted with a radiator, hood panels, and firewall and then road-tested on public highways prior to being sent to completion for its bodywork. No less than 120 coachbuilders (mostly British) supplied bodies, like as Freestone & Webb, Gurney Nutting, Vickers; the most prolific of which was Vanden Plas, which provided 669 bodies from 1922–1931. Bentley’s relationship with Vanden Plas began in 1922, and by 1924, the company bodied 84 Bentleys alone. In 1925, Vanden Plas leased a portion of their premises to Bentley for the latter’s service department, securing their role as the coachbuilder of choice for Bentley.
A total of 720 4½ Litre cars were produced between 1927 and 1931, including 55 cars with a supercharged engine popularly known as the Blower Bentley. The 4½-Litre was produced for four years, all but nine made being built on the 3-Litre's 'Long Standard', 10' 10"-wheelbase chassis. A 4½ Litre Bentley won the 24 Hours of Le Mans in 1928. Though the supercharged 4½ Litre Bentley's competitive performance was not outstanding, it set several speed records, most famously in 1932 at Brooklands with a recorded speed of 222.03 km/h (138 mph).
Although the Bentley 4½ Litre was heavy, weighing 1,625 kg (3,583 lb), and spacious, with a length of 4,380 mm (172 in) and a wheelbase of 3,302 mm (130.0 in), it remained well-balanced and steered nimbly. The manual transmission, however, required skill, as its four gears were unsynchronised
The robustness of the 4½ Litre's latticed chassis made of steel and reinforced with ties was needed to support the heavy cast iron inline-four engine
The engine was "resolutely modern for the time. The displacement was 4,398 cc (268.4 cu in): 100 mm (3.9 in) bore and 140 mm (5.5 in) stroke. Two SU carburetters and dual ignition with Bosch magnetos were fitted. The engine produced 110 hp (82 kW) for the touring model and 130 hp (97 kW) for the racing model. The engine speed was limited to 4,000 rpm. A single overhead camshaft actuated four valves per cylinder, inclined at 30 degrees. This was a technically advanced design at a time where most cars used only two valves per cylinder. The camshaft was driven by bevel gears on a vertical shaft at the front of the engine, as on the 3 Litre engine.
The Bentley's tanks - radiator, oil and petrol - had quick release filler caps that opened with one stroke of a lever. This saved time during pit stops.
Brakes were conventional, consisting of 17-inch (430 mm) drum brakes finned for improved cooling and operated by rod. Semi-elliptic leaf springs were used at front and rear.