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).
Blueprint graph showing ignition advance curves for high power heads during Bentley single cylinder tests.
| Identifier | ExFiles\Box 134\2\ scan0033 | |
| Date | 23th April 1957 guessed | |
| BENTLEY SINGLE CYLINDER TESTS SHEET 11 V 1755 IGNITION ADVANCE CURVES - HIGH POWER HEADS. HIGH POWER CYLINDER & HEADS TO L.C's 4075, 4125, 4157 SODIUM COOLED EXHAUST VALVE ZENITH CARBURETTOR (36 M/M CHOKE) COMPRESSION RATIO - 6.13 & 6.17 OPEN EXHAUST FUEL - DTD 224 MINIMUM ADVANCE FOR MAXIMUM POWER 5% POWER DROP RPM IGNITION ADVANCE (FLYWHEEL) | ||