Rolls-Royce–Bentley L-series V8 engine as the "six and a quarter" litre engine. When new, the Rolls-Royce/Bentley V8 was rumoured to be an American engine design licence-built, but it was developed in-house by Rolls-Royce and Bentley engineers. This can be seen in its design characteristics, with features like an aluminium alloy cylinder block with wet liners, gear-driven camshaft, (initially) outboard spark plugs and porting inspired by the Rolls-Royce Merlin aircraft engine. The bore spacing of 4.75" was unlike any American V8 engine and the firing order was 1-5-4-8-6-3-7-2 something uncommon in any period American OHV V8. The deep skirted crankcase design is also rare with
Rolls-Royce V8 engine of work under Les Maddock and Colin Weston, the first result of which was the N80, a 4-valve, double overhead camshaft, 5.0 litre V8. This successfully ran first stage 1000 hours testing straight off the drawing board without incident. Subsequently, the marketing brief foresaw the requirement for a higher capacity version and the N81, 6.0 litre version, was designed. The project was stopped around 1991 with further development of the L410 engine that enabled emissions requirements to be met using a pre-catalyst assembly at substantially lower investment. Rolls-Royce V8 engine In the history of Rolls-Royce automobiles, only two distinct series