The Rolls-Royce–Bentley L-series V8 engine was a big-block engine introduced in 1959. Built in Crewe, it was used on most Rolls-Royce and Bentley automobiles in the four decades after its introduction and was used in the Bentley Mulsanne until 2020.
With BMW‘s acquisition of the rights to use the Rolls Royce name in 1998, Rolls-Royce Motor Cars began using BMW supplied V12 engines but Bentley Motors Limited under Volkswagen ownership continued to use highly modified versions of the L series on its Arnage, Azure, Brooklands and Mulsanne models, with VAG W-12 and V8 engines being used in its Continental GT, Flying Spur and Bentayga models.
The first engine of V8 configuration was developed in 1904 by the Marmon Motor Car Company in the United States. It was experimental, however, and did not find its way into a passenger vehicle. Rolls-Royce premiered the world’s second V8 engine in 1905 for their Rolls-Royce V-8Legalimit – governed not to exceed the legal speed limit in Britain at the time of 20 mph (32 km/h). It was not a success, with only three made and just one sold, which was soon returned to the factory to be scrapped. It was another decade before Cadillac pioneered a mass production V8-engined automobile.
Rolls-Royce acquired Bentley in 1931 and continued to use Bentley engines alongside their own for a time, although none was a V8. Prior to World War II, Rolls-Royce had developed a 7.3-litre V-12 for the Phantom III, which was succeeded by the inlet-over-exhaust B60 straight-6 and B80 straight-8 series of engines. The B80 powered the Phantom IV limousine, whilst the 4.3-litre B60 was used until 1955 to power the Rolls-Royce Silver Wraith and Silver Dawn and the Bentley Mark VI. The B60’s bore was enlarged in 1955, increasing the displacement to 4.9 litres, that engine being known as the B61.
The need for a new engine was recognised by Rolls Royce in the early 1950s and its development began in 1952, bearing no relation to the 1905 Rolls-Royce V8. The result was a series of V8 engines known as the L series, more specifically the “L410” for its bore size of 4.1 in (104.14 mm), in keeping with company practice.
Developments of the L410 continued in production powering Rolls-Royces up to 1998 and Bentleys into the 21st century. Bentley, under Volkswagen ownership since 1998, continues to develop the L410 for its range of cars. Rolls-Royce ceased using the L410 with the switch to BMW ownership of that brand in March 1998 and introduction of a BMW sourced V12 engine in the Rolls-Royce Silver Seraph.
Since 1998 therefore, development and use of the L410 engine can be said to have been exclusively a Bentley enterprise.
The factory nomenclature for the L-series V8 engines, in chronological order, is as follows:
- L380 1950s 5,204 cc (317.6 cu in) initial development version
- L410 1959 6,230 cc (380 cu in) production version powering Silver Cloud II, Phantom, and S2 series
- L425 1965 7,439 cc (454.0 cu in) experimental version
- L410B 1965 6,230 cc (380 cu in) updated production version powering Silver Shadow and T series
- L410 1970 6,750 cc (412 cu in) production version, capacity increase achieved by ‘stroking’ to 3.9-inch (99.06 mm)
- L410E 1970s 7,269 cc (443.6 cu in) development version with 4.2-inch (106.7 mm) stroke
- L380 1970s 5,352 cc (326.6 cu in) “Thermodynamically Optimised Porsche (TOP)” experimental version
- L410D 1982 6,750 cc (412 cu in) turbocharged production version installed in Bentley Mulsanne
- L410I 1986 6,750 cc (412 cu in) fuel injected version
- L410IT 1987 6,750 cc (412 cu in) fuel injected production version in Bentley Mulsanne Turbo
- L410ITI 1991 6,750 cc (412 cu in) fuel injected, turbo, intercooled production version of Bentley Turbo R & S and Continental R & S
- L410MT 1997 6,750 cc (412 cu in) low pressure turbo
- L410MT/S 1997 6,750 cc (412 cu in) turbo
- L675 1998 6,750 cc (412 cu in) development name for Arnage version of the turbo, later reverted to “L410”
- L410TT 2007 6,750 cc (412 cu in) production version introducing twin MHI turbochargers with intercooler
- L410HT 2009 6,750 cc (412 cu in)variable cam phasing “high-torque” production version for 2009 Mulsanne