Bentley 3 Litre

Bentley 3 Litre
Blue label tourer by Park Ward 1924
Overview
Manufacturer	Bentley Motors Limited, Cricklewood, London
Production	1921–1929 1622 produced[1]
Designer	Walter Owen Bentley
Body and chassis
Class	Sports car
Body style	as arranged with coachbuilder by customer
Powertrain
Engine	3.0 L OHC 4-valve I4
Dimensions
Wheelbase	108 in (2,743 mm) 117.5 in (2,984 mm) 130 in (3,302 mm)
Chronology
Successor	4 1⁄2 Litre

The Bentley 3 Litre was a car based on a chassis manufactured by Bentley. The company's first car, it was introduced in 1919 and the chassis was made available to customers' coachbuilders from 1921 to 1929. The Bentley was larger than the Bugattis that dominated racing at the time, but strength and innovative technology compensated for the extra weight. The 4000 lb (1800 kg) car won the 24 Hours of Le Mans in 1924, with drivers John Duff and Frank Clement, and again in 1927, this time in Super Sports form, with drivers S. C. H. "Sammy" Davis and Dudley Benjafield. Its weight, size, and speed prompted Ettore Bugatti to call it "the fastest lorry in the world."

Coachwork

Rare original saloon, a Weymann by Gurney Nutting 1926
Few saloon bodies have not been replaced by new touring bodies

The 3 Litre was delivered as a running chassis, with Bentley referring many customers to Vanden Plas for standard bodies. Most were tourers, but some variety was inevitable with custom coachwork.^[2] Customers included Prince George, Duke of Kent, Gertrude Lawrence, and Beatrice Lillie.

Engineering

Red label Speed high compression twin SU Engine PH1468 delivered March 1926 in a tourer with licence plate KM 2321

The 3.0 L (2,996 cc or 183 cu in) straight-4 engine had several technical innovations. The engine was one of the first production car engines with 4 valves per cylinder and an overhead camshaft. The bevel-geared shaft drive for the camshaft was designed by ex-Royal Flying Corps engineer Clive Gallop.^[3] The engine was also among the first with two spark plugs per cylinder, pent-roof combustion chambers, and twin carburetters. It was extremely undersquare, optimized for low-end torque, with a bore of 80 mm (3.1 in) and a stroke of 149 mm (5.9 in). To increase durability, the iron engine block and cylinder head were cast as a single unit.

Power output was around 70 hp (52 kW), allowing the 3 Litre to reach 80 mph (129 km/h). The Speed Model could reach 90 mph (145 km/h); the Super Sports could exceed 100 mph (161 km/h).

A four-speed gearbox was fitted.

Only the rear wheels had brakes until 1924, when four-wheel brakes were introduced.^[4]

Variants

Red label Speed 4-seater tourer 1927

There were three main variants of the 3 litre and they became known by the colours commonly used on the radiator badge. There is, however, no definitive rule controlling badge colours and the factory would supply any colour requested.

Blue label

This was the standard model with 117.5 in (2,984 mm) wheelbase from 1921 to 1929 or long 130.0 in (3,302 mm) wheelbase from 1923 to 1929.^[4]

Red label

This used a 5.3:1 high compression engine in the 117.5 in (2,984 mm) wheelbase chassis and was made from 1924 to 1929.^[4]

Green label

Made between 1924 and 1929 this was the high performance model with 6.3:1 compression ratio and short 108 in (2,743 mm) wheelbase chassis. 100 mph (160 km/h) performance was guaranteed.^[4]

Production

Red label Speed open 2-seater by H J Mulliner 1926

The 3 Litre car was shown at the 1919 London Motor Show, but the engine had not yet been finished. It took two years to get the engine right, with the first customer delivery in September 1921. Production lasted through 1929, by which time the car had been surpassed by Bentley's own 4½ Litre car.

• Experimental: 3
• 3 Litre: 1088
• Speed Model: 513
• Super Sports: 18

Car later rebuilt and supercharged

In the winter of 1926/7 the factory's service department created the first supercharged Bentley when chassis number 220 FR5189 had a Roots type blower fitted to its 3-litre engine. This pre-dated the Birkin supercharged Bentleys by two years. Like the later 4½ litre supercharged cars its blower was crankshaft-driven and mounted in front of the radiator between the dumb irons. Unlike them its carburettor was mounted on the left side of the engine block. A rather circuitous intake tract carries the fuel-air mixture forward from there to the blower. On 4½ litre cars the carburettor is mounted on the blower, as commonly done on other supercharged British cars with front-mounted blowers.

First supercharged Bentley, FR5189

FR5189's Engine

FR5189 at Lime Rock Park

Survivors

Blue label #19 delivered December 1921

The oldest surviving production Bentley is 3 Litre chassis number 3. The first Bentley sold, it was delivered to its original owner in 1921. Bodied by UK coachbuilder R. Harrison & Son, chassis number 3 has engine number 4 and UK registration AX 3827. In 2011 it sold at auction for $962,500 including buyer's premium.^[5][6][7]

An original, unrestored 1927 3 Litre Speed Model (Red Label), chassis #1209 DE, is a part of the permanent collection at the Simeone Foundation Automotive Museum in Philadelphia, PA, USA. The car retains all of its original components and is the only Bentley to compete in pre-war road racing competition in the USA.^[8]

References

Wikimedia Commons has media related to Bentley 3-Litre.

External links

• Reality television: My brother, my Bentley