Graph of ignition timing curves for a 4 1/4 Litre Bentley O.H.C. engine, comparing standard and converted configurations.
| Identifier | ExFiles\Box 113\5\ scan0172 | |
| Date | 17th October 1936 | |
| IGNITION. 4 1/4 LITRE BENTLEY O.H.C. (CONVERTED UNIT). S.8. UNIT Nº B.23. ① STD. 4 1/4 LITRE ENGINE (6·5:1 C/R.). ⓐ IDEAL LINE (MIN. ADV. FOR MAX. POWER). ⓑ LINE TO CUT OUT DETONATION. Associated with SHELL Nº 1 PETROL. ② O.H.C. CONVERSION (6·0:1 C/R) (SPEC: R.M.C./W.S.C. 1/L.S 17.10.36). ⓐ IDEAL LINE (MIN. ADV. FOR MAX. POWER). ⓑ LINE TO CUT OUT DETONATION. Associated with SHELL Nº 1 PETROL. ⓒ LINE TO CUT OUT DETONATION. Associated with SHELL Nº 3 PETROL. CRANKSHAFT DEGREES B.T.D.C. R.P.M. C.T.S. Graph labels: 1a, 1b, 2a, 2b, 2c. Y-Axis values: 0, 10, 20, 30, 40, 50. X-Axis values: 0, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000. | ||
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).