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 the power performance of two different camshafts for a Bentley III engine.
| Identifier | ExFiles\Box 108\2\ scan0204 | |
| Date | 16th January 1939 guessed | |
| CAMSHAFT COMPARISON BENTLEY III POWER S 65 COMP. RATIO 6.6:1 B III INDUCTION SYSTEM RM{William Robotham - Chief Engineer} 522 PISTONS (.170) "ETHYL" PETROL ① CAMSHAFT E.B. 3466 (TIMING @ .030 CLCE) I.O. 4.5° AT E.O. 38° BB I.C. 47° AB E.C. 3.5° AT ② CAMSHAFT EX 31550 (TIMING @ .030 CLCE) I.O. 3.5° AT E.O. 41° BB I.C. 46° AB E.C. 5° AT ⓐ OPEN EXHAUST ⓑ SILENCED B I SYSTEM COMPLETE B.H.P. B.M.E.P. R.P.M. | ||