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 comparing performance with different exhaust valve sizes and timings on a Bentley single cylinder head.
| Identifier | ExFiles\Box 133\2\ scan0072 | |
| Date | 1st July 1937 guessed | |
| V1713 Sheet 8 BENTLEY SINGLE CYLINDER TESTS COMPARISON OF EXHAUST VALVE SIZE (RAMP CYLINDER HEAD) NATURALLY ASPIRATED OPEN EXHAUST FUEL - DTD224 NORMAL INLET VALVE (1.500 DIA) COMPRESSION RATIO - 6.4:1 VALVE LIFT - .400" CURVE 1 - STD. EXH. VALVE (1.300 DIA) & NORMAL TIMING. I.O. 4°E; I.C. 51°L; E.O. 53°E; E.C. 9°L CURVE 2 - LARGE EXH. VALVE (1.450 DIA) & NORMAL TIMING CURVE 3 - LARGE EXH. VALVE (1.450 DIA), CYL. HEAD TREPANNED AROUND EXH. VALVE SEATING TO A RADIAL DEPTH OF .075". NORMAL TIMING CURVE 4 - AS (3), BUT WITH SHORT EXH. DURATION. E.O. 48°E; E.C. 1°L CURVE 5 - AS (3), BUT WITH MUCH SHORTER EXH. DURATION. E.O. 45°E; E.C. 7°E BRAKE HORSE POWER R.P.M. B.M.E.P. (LBS/SQ. IN.) | ||