Bentley 8 Litre

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Bentley 8 Litre chassis
Bentley 8 Litre (1930) (14912429238).jpg
Weymann saloon by Mulliner the second car made and
W. O. Bentley's personal transport
Manufacturer Bentley Motors Limited
  • 1930–1932
  • 100 produced
Assembly Cricklewood, London
Designer W. O. Bentley
Body and chassis
Class Luxury car
Body style purchaser to arrange with own coachbuilder[1]
Layout FR layout[2]
Related Bentley 4-Litre (economy version)
Engine SOHC 8 L I6[3]
  • Manual gearbox, 4-speeds and reverse
  • Single-dry-plate clutch
  • Hypoid bevel final drive
  • 138 in (3,505 mm)[5] (3 only)
  • 144 in (3,658 mm)[2]
  • 156 in (3,962 mm)[2]
  • (12') 201.25 in (5,112 mm)
  • (13') 213.25 in (5,417 mm)
Width 68.5 in (1,740 mm)[2]
Height depending on coachwork
Kerb weight 2.5 tonnes or more, depending on coachwork
Bentley 8-litre engine
Bentley 8 Litre saloon by Mulliner 1931 f3q 640 by 480.JPG
Production 1930–1932
Combustion chamber
Configuration 6-cylinder in-line
Displacement 7,983 cubic centimetres (487 cu in)
Cylinder bore 110 mm (4.3 in)
Piston stroke 140 mm (5.5 in)
Cylinder block alloy
Cylinder head alloy non-detachable – see block
Valvetrain single overhead camshaft driven by patented triple connecting rods; 4-valves-per-cylinder[3]
Compression ratio 5:1
Fuel system [3]
Fuel type petrol
Cooling system Water-cooled, with pump, fan and thermostatically-controlled shutters[3]
Power output
  • 220 bhp (160 kW; 220 PS) @3,300rpm
  • Tax rating 44.9 hp[6]

The Bentley 8 Litre was a luxury car based on the largest rolling chassis made by Bentley Motors Limited at Cricklewood, London. Announced 15 September 1930, it was also the last completely new model by Bentley before the company's financial collapse and forced sale to Rolls-Royce Limited; a 4-Litre engine in a shortened chassis was announced on 15 May 1931. Intended to provide the basis for a super-luxury car for very wealthy buyers, the 8 Litre chassis was introduced a year into the Great Depression. Sales of the 8-litre were too slow to turn the company's finances around and, less than nine months after the 8-litre's introduction, Bentley Motors was placed into receivership.

Design and specifications[edit]


The straight-six engine used a one-piece iron block and non-detachable cylinder head with a crankcase made from Elektron, a magnesium alloy. It featured an overhead camshaft driven by a Bentley patented "three-throw drive" system of triple connecting rods[4][7] with, like all earlier Bentleys, four valves per cylinder and twin-spark ignition (coil and magneto), which were state-of-the-art at the time.[5][8] The engine had a bore of 110 mm (4.3 in) and a stroke of 140 mm (5.5 in),[3][9] giving a capacity of 7,983 cc (487.2 cu in).[3][10][9] Pistons were of an aluminium alloy.[11]

Both engine and gearbox were mounted each at three points on rubber to isolate the chassis and body from vibration.[11]


An entirely new design of four-speed gearbox provided four speeds (constant mesh third) and reverse[3][12] with a single-plate dry clutch which sent power through a hypoid bevel final drive to the rear axle and its 21" Rudge-Whitworth wire centre-lock wheels.[3]


The chassis was a ladder frame with large tubular steel cross-members downswept from the front and rear axles towards the centre to lower the centre of gravity.[3]

Neither engine nor gearbox contributed to the bracing of the chassis.[3]

Suspension by long semi-elliptic leaf springs was controlled by double acting dampers, friction on the front and hydraulic on the rear axle, and all four wheels were fitted with Dewandre vacuum-servo-assisted 400 mm (15.7 in) drum brakes, the forward brakes being of Bentley-Perrott design.[11]

Steering was by worm and sector and castor action could be adjusted to suit individual taste.[3]

There was centralised chassis lubrication[3][13] including the gaitered springs but not for the front axle or the clutch withdrawal system.[3]

The 8-Litre chassis was available with either a 144 in (3,700 mm) wheelbase or a longer 156 in (4,000 mm) wheelbase.[3][13] Three were built with a 138 in (3,500 mm) wheelbase.[citation needed]

The manufacturer claimed a maximum speed of approximately 125 mph (201 km/h).[5] A speed in excess of 105 mph (169 km/h) was guaranteed by the manufacturer.[3]


Weymann saloon by H. J. Mulliner YF5001: the first 8 Litre made; built for entertainer Jack Buchanan.[14]

Announced on 15 September 1930[4] and launched at the London Olympia Motor Show in October 1930,[3] the 8 Litre Bentley was noted for its tractability and smoothness; it could be driven from walking pace to highway speeds in top gear without effort.[13][9]

As a result of the Great Depression, the 8 Litre did not sell well enough to improve Bentley's financial situation.[12][9] The chassis was priced at £1,850,[3] roughly equivalent to £293,000 in 2010.[15]

Only 100 of these cars were made[5][13] of which 35 were on the shorter wheelbase and 65 were on the longer wheelbase.[13] Fewer than 25 were fitted with open bodies.[citation needed] It is suggested[by whom?] that the cost of the development of the car was a prime reason for Bentley Motors going bankrupt.[citation needed]

Bentley made one more attempt at financial recovery by installing modified Ricardo 4-litre engines in a shortened 8-Litre chassis and selling the result as the Bentley 4 Litre.[16][17] Announced on 15 May 1931,[18] only 50 were made before Bentley Motors Ltd. was placed into receivership.[16]

When Rolls-Royce bought Bentley Motors from the receiver[19] in November 1931[20] it discontinued production of the 8-Litre[13][12] and disposed of all spare parts for it.[citation needed]


Saloon rebodied with a replica tourer body.

78 Bentley 8 Litre cars were known to survive as at mid-2011.[21] Many of these have had their original limousine or saloon bodies replaced by new replica tourer bodies.[22] As a result, Bentley 8 Litres with original bodies are much sought after by collectors.[citation needed]

The only Bentley 8 Litre with an American body, which was also the first Bentley with an all-metal body, was built by the W.M. Murphy Company of Pasadena for a customer in Santa Barbara, California.[23]

McKenzie's Garages, a specialist in Rolls-Royce and Bentley cars, modified four 8 Litres in the 1930s: YM5050, with shortened chassis, lowered radiator and bulkhead, and triple SU carburettors,[24] YR5083, with a higher-ratio rear axle and triple SU carburettors,[25] YX5117, with a lowered and shortened chassis and triple SU carburettors,[26] and YX5121, with a shortened and lowered chassis and a tuned engine.[27]


  1. ^ History By Chassis – List of all W. O. Bentleys with original chassis nos. 8 Litre
  2. ^ a b c d e "Bentley Motors Limited. Display Advertising" The Times (London). Friday, 15 May 1931. (45823), p. 11.
  3. ^ a b c d e f g h i j k l m n o p q "A Great British Car the 8-lire Bentley.". The Observer (London UK). 25 January 1931. p. 26. 
  4. ^ a b c "Cars of 1931. (FROM OUR MOTORING CORRESPONDENT). The New Bentley, Silence and Vibration Studied." The Times (London). Monday, 15 September 1930. (45618), p. 7.
  5. ^ a b c d Ebyl 2001, pp. 192–197.
  6. ^ RAC Rating
  7. ^ Brooks 2009, pp. 27, 32.
  8. ^ Robson 1990, pp. 24, 27.
  9. ^ a b c d Posthumus 1977, p. 115.
  10. ^ Robson 1990, p. 24.
  11. ^ a b c "Cars of To-Day. (OUR MOTORING CORRESPONDENT). Eight-litre Bentley." The Times (London). Tuesday, 9 December 1930. (45691), p. 19.
  12. ^ a b c Robson 1990, p. 27.
  13. ^ a b c d e f Brooks 2009, p. 32.
  14. ^ "1931 Bentley 8 Litre Chassis No. YF5001 Engine No. YF5001 Registration No. GK 672". Vintage Bentleys .org. Vintage Bentleys .org. Archived from the original on 4 January 2014. Retrieved 4 January 2014. 
  15. ^ Measuring Worth
  16. ^ a b Lot 244: Bentley 4-Litre/8-Litre Le Mans-style Tourer, Motorbase
  17. ^ HISTORY OF MARQUES: BENTLEY – British, Sportscars.TV
  18. ^ BY OUR MOTORING CORRESPONDENT.. "A New Bentley." The Times (London). Friday, 15 May 1931. (45823), p. 13.
  19. ^ Feast 2004, pp. 64–65.
  20. ^ King 2008, p. 17.
  21. ^ Johnson 2011, p. 11.
  22. ^ Buckley 2004, pp. 42–43.
  23. ^ 1931 Bentley 8-Liter, Conceptcarz
  24. ^ Hay, pp. 204–206.
  25. ^ Hay, p. 128.
  26. ^ Hay, pp. 231–235.
  27. ^ 1931 Bentley 8 Litre Chassis No. YX5121 Engine No. YX5122 Registration no. GW 2926, Vintage Bentleys .org