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 Twenty Rolls-Royce Twenty The Rolls-Royce Twenty built between 1922 and 1929 was Rolls-Royce's "small car" for the 1920s and was produced alongside the 40/50 Silver Ghost and the successor to the 40/50, the Phantom. It was intended to appeal to owner drivers but many were sold to customers with chauffeurs. A new inline-6 cylinder overhead valve engine was designed for the car of 3127 cc with a bore of 76 mm and stroke of 114 mm. Unlike the Silver Ghost engine, the cylinders were cast in one block and the cylinder head was detachable. Both coil and magneto ignition were fitted.