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).
Graph showing the effect of increased valve lift on a standard cylinder head at different RPMs.
| Identifier | ExFiles\Box 92\2\ scan0144 | |
| Date | 9th August 1931 guessed | |
| RM{William Robotham - Chief Engineer} P22 EFFECT OF INCREASED VALVE LIFT ON 4.78 C/R STD. CYLINDER HEAD 1.9" DIA. VALVE THROAT 114° CAMSHAFT TO E62448 OPEN EXHAUST VALVE LIFT .525 VALVE LIFT .470 CLAUDEL TWIN CARBS 1.4" CHOKES VALVE TIMING DIAGRAM: EX, IN, 3, 12, 58, 54 LEFT Y-AXIS (B.H.P.): 80, 90, 100, 110, 120, 130, 140, 150, 160, 170 BOTTOM X-AXIS (R.P.M.): 500, 1000, 1500, 2000, 2500, 3000, 3500 RIGHT Y-AXIS (B.M.E.P. LBS/SQ. IN): 60, 70, 80, 90, 100, 110 RIGHT Y-AXIS (INDUCTION DEPN. INS HG): 2.80, 3.90 | ||