From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Particulars of the 2-Litre Racing Sunbeam engine and its components.
| Identifier | WestWitteringFiles\O\2January1926-March1926\ Scan33 | |
| Date | 28th January 1926 guessed | |
| PARTICULARS OF 2-LITRE RACING SUNBEAM. GENERAL DATA. Number of cylinders 6. Bore 67 mm = (2.65") Stroke 94 " = (3.7") Stroke/bore ratio 1.4 Total swept volume = 1.988 c.c. = (121.3 cu.ins.) Compression ratio (with supercharging 1925) 6.15/1. Compression ratio (with normal induction 1923) 7.2/1. Comparative performance at 5000 r.p.m. :- Supercharged :- 143 H.P. = 186.5 lbs/sq.in. B.M.E.P. Un- " :- 107 H.P. = 139.5 " " Fuel used - standard Shell. Max. speed (limit given for racing) 5200 r.p.m. CYLINDERS. The cylinders are in blocks of three with welded-on sheet steel water jackets. They provide hemispherical combustion chambers with two valves per cyl. and central sparking plug position. CRANKSHAFT. A seven-bearing counterweighted crankshaft runs in roller bearings. The crankshaft is not built up - the roller cages being split diametrically for the purpose of assembling. At the forward end a Rootes Blower is driven through a laminated spring drive - the driving dogs being fitted with fibre blocks. At the rear end is a slight flywheel and a multiple (steel) plate clutch, a four-speed gearbox constructed as a unit with the engine, completing the arrangement. contd:- | ||