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).
Performance graph from Bentley single cylinder tests comparing the power output of different high-power cylinder heads.
| Identifier | ExFiles\Box 134\2\ scan0022 | |
| Date | 27th May 1935 guessed | |
| V1744 BENTLEY SINGLE CYLINDER TESTS. SHEET 1 POWER OUTPUT - HIGH POWER HEADS. HIGH POWER CYLINDER & HEADS TO L&C 4075, 4123 & 4157 SODIUM COOLED EXHAUST VALVE 1.500" DIA. ZENITH CARBURETTOR (36% CHOKE) OPEN EXHAUST FUEL = DTD 224 VALVE TIMING:- I.O. 2°E ; I.C. 28°L ; E.O. 51°E ; E.C. 7°L. TWIN INLET HEAD (C.R. = 6.13) DITTO - (C.R. = 6.5) SINGLE INLET HEAD (C.R. = 6.17) (UNCOOLED EXHAUST VALVE) STANDARD BENTLEY NORMAL TIMING 32% CHOKE C.R. = 6.4 BRAKE HORSE POWER R.P.M. B.M.E.P. (LBS/SQ. IN.) SP.{Mr Spinney} FUEL CONS. (PTS/BHP/HR) | ||