Bentley’s ‘Great Eight’ finishes production
The mighty Bentley 6¾-litre V8 engine – the longest serving V8 design in continuous production – has finally reached the end of its handcrafted manufacturing run. In production for more than 60 years, and with the same configuration and bore spacing as the very first version from 1959, the last L-Series engine will spend its life powering the 30th and final specially commissioned Mulsanne 6.75 Edition by Mulliner, an exclusive series that closes Mulsanne production and celebrates the life of its iconic engine with a myriad of V8-inspired details including badging, blueprint graphics and even ventilation ‘organ stops’ featuring a miniature version of the oil cap.
The development of the first Bentley V8 engine began not long after the company moved to its current headquarters in Crewe. In the early 1950s, Jack Phillips, Senior Engine Designer, was asked to undertake a confidential study to find a replacement for the six-cylinder engine used in the Bentley Mark VI, R-Type and S1. His brief was to build an engine at least 50 per cent more powerful, while occupying the same space under the bonnet with no increase in weight.
The first L-Series V8 saw service in the 1959 Bentley S2, was 14kg lighter than the six-cylinder it replaced, and developed around 180bhp, deemed ‘adequate’ by Bentley at the time. The car also featured air conditioning, power steering, electrically-operated ride control and press button window lifts (now called power windows), making it the most luxurious equipment for a car of that era.
The original V8 engine then had to be redesigned to fit into the 1965 Bentley T-Series. The engine design team focused on improving performance, while reducing the overall engine dimensions to fit the space available under a now lowered bonnet. Engine capacity was increased to the eponymous 6¾-litres in 1971 through an increase in stroke from 3.6 to 3.9 inches that delivered even more torque.
The next big change was the arrival of the first iteration of the Bentley Mulsanne in 1980, which brought with itself major changes to the V8, along with the need for stricter emission controls and improved passenger safety in the event of a front-end impact. The latter included a collapsible water pump, which effectively shortened the engine by 101mm.
The next big change to the engine was for the launch of the Mulsanne Turbo. With the fitment of a turbocharger, the 6¾-litre engine become the first forced-induction Bentley engine since Tim Birkin’s Blower Bentleys of the 1920s. Power and torque made a steep change, and the single turbo setup was eventually replaced by a twin-turbo design along with fuel injection and full electronic control.
With the modernisation of the Crewe facility from 1998 and an increase in production, the V8 engine also underwent on-going development. Cars such as the 2008 Bentley Brooklands V8 benefitted greatly and although separated by almost 50 years of development, the Brooklands’ V8 design clearly had its roots in the 1959 original, with almost 200 per cent more power and torque.
For the launch of the new Mulsanne in 2010, the V8 underwent a major overhaul, with a new crankshaft, new pistons, new connecting rods and new cylinder heads that brought variable valve timing and cylinder deactivation - the latter being a first for Bentley, but since adopted across the entire model range. Power stayed above 500bhp, while torque figures peaked at 1100 Nm – for a time, the L-series V8 made more torque than any other automotive engine in the world. At the same time, the re-engineered V8 delivered a 15 per cent improvement in fuel economy in emissions. The engine now reaches the end of its development and production run, but will live in for decades to come in the beloved cars of Bentley’s customers.
Every one of the 36,000 L-Series engines built over the last 60 years has been created by hand in the engine workshops of Bentley’s Crewe headquarters. Even the modern engine takes 15 hours to build. Once completed, and after thorough testing, the engine is signed off by one of Bentley’s engine specialists, as it has been for decades – with a plate denoting their signature affixed to the front of the engine.
With the Mulsanne completing production once the thirty 6.75 Edition cars are built, the all-new Flying Spur will become Bentley’s flagship model, as the pinnacle of Bentley’s exquisite range of luxurious cars. With the Flying Spur to receive a hybrid powertrain by 2023, the move symbolises Bentley’s commitment to change and its journey to define the future of sustainable luxury mobility. The world’s most sought-after luxury car brand has already taken its first step on the road towards electrification with the launch of the Bentayga Hybrid - the luxury SUV sector’s first, true plug-in hybrid and the most efficient Bentley ever.
Commenting on the 6 ¾ now concluding its production run, Peter Bosch, Bentley’s Member of the Board for Manufacturing, said, “Our venerable 6¾-litre V8 has powered the flagship Bentley for more than six decades, and so has earned its retirement. I am extremely proud of the generations of skilled craftspeople meticulously assembling every one of these engines by hand over the years. That this engine stood the test of time for so long is testament to the ingenious engineers who kept making the engine ever more powerful, refined and reliable. Now, we look forward to the future of Bentley, powered by our exceptional W12, sporting 4.0-litre V8 and of course our efficient V6 Hybrid - the start of our journey to electrification.”
