Rolls-Royce Phantom I

Introduced in 1925, the New Phantom was Rolls-Royce's second 40/50 hp model. To differentiate between the 40/50 hp models, Rolls-Royce named the new model "New Phantom" and renamed the old model "Silver Ghost", which was the name given to their demonstration example, Registration No. AX201.[2] The name Phantom was a nod to the previous "Silver Ghost", remarking on the vehicles "extraordinary stealth"[3] and quietness in comparison to other vehicles offered at the time. When the New Phantom was replaced by another 40/50 hp model in 1929, the replacement was named Phantom II and the New Phantom was commonly referred to as Phantom I to this day. While Rolls-Royce themselves did not use the term "Phantom I" until their recent acquisition by BMW Group, New Phantoms were referred to as such in period and are commonly called Phantom I by enthusiasts, concours events, and owner's clubs.[4]

One major improvement over the Silver Ghost was the new pushrod-OHV straight-6 engine.[4][5] Constructed as two groups of three cylinders with a single detachable head,[4] the engine was described by Rolls-Royce as producing "sufficient" power.[5] The engine used a 4¼ in (107.9 mm) bore and undersquare 5½ in (139.7 mm) stroke for a total of 7.7 L (7,668 cc (467.9 cu in)) of displacement. In 1928, the cylinder heads were upgraded from cast iron to aluminium; this caused corrosion problems. The separate gearbox connected through a rubberised fabric flexible coupling to the clutch and through a torque tube enclosed drive to the differential at rear, as in the Silver Ghost.

The New Phantom used the same frame as the Silver Ghost,[4] with semi-elliptical springs suspending the front axle[6] and cantilever springs suspending the rear axle.[6][7] 4-wheel brakes with a servo-assistance system licensed from Hispano-Suiza were also specified,[4][5][8] though some early US models lacked front brakes.

Like the Silver Ghost, the New Phantom was constructed both at Rolls-Royce's Derby factory in the United Kingdom and at a factory in Springfield, Massachusetts in the United States.[4][5] The US factory produced New Phantoms from 1926 to 1931.[5]

Principal differences between the US and UK models included wheelbases and transmissions. Both versions were specified with the same standard 143½ in (3644.9 mm) wheelbase; the long-wheelbase U.S. model was 146½ in (3721.1 mm) and the UK 150½ (3822.7 mm). Both versions used a single dry-plate clutch, with US models equipped with a centre change 3-speed transmission and UK a 4-speed.[5]

Other minor differences include fuel gauge placement, with the UK New Phantom's at the tank but some US models having one on the dash, and manual central lubrication systems. The UK Phantom employed Enots nipples, some times as many as 50, which required attachment of a special Enots oil pressure gun and needed time-consuming service at 500, 1000 and 2000 mile intervals; the US model used a centralized Bijur system which lubricated all the oiling points with a stroke of a single pump.[6]