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 power and detonation characteristics for a Bentley III engine with different compression ratios.
| Identifier | ExFiles\Box 97\1\ scan0133 | |
| Date | 1st March 1938 | |
| BENTLEY III COMPRESSION RATIO POWER & DETONATION S.30 MARCH 1938 ① STD. WRAITH CYL. HEAD (131 CCS.) GASKET .030" C/R = 6.1:1 ② WRAITH CYL. HEAD (119 CC'S) (.100 OFF FACE) GASKET .030" C/R = 6.5:1 ⓐ MIN. ADV. FOR MAX. POWER ⓑ LINE TO AVOID DETONATION VALVE TIMING (@ .030 CL'CE) I.O 2° B.T. E.O 41° B.B. I.C 40° A.B. E.C 3° B.T. REDLINE PETROL (N° 3 SPIRIT) PROD. BENTLEY EXH. SYSTEM. B. III AIR BEND & SILENCER SPEC. M.P.S/C.P.I/V.S. 24.1.38. B. III N°1 UNIT. SPARK POSITION B.T.D.C. R.P.M. B.M.E.P. CTS{C. Trot Salt - Carburation} | ||