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).
Use of higher compression heads on Bentley engines and the development of a suction control scheme for ignition advance.
| Identifier | ExFiles\Box 86\1\ scan0096 | |
| Date | 25th September 1934 | |
| x219 w/s. To Sg.{Arthur F. Sidgreaves - MD} from E.{Mr Elliott - Chief Engineer} c. Mr. Hs.{Lord Ernest Hives - Chair} re Bentley. Referring to Sg.{Arthur F. Sidgreaves - MD}8/E.24.9.34 and previous correspondence concerning the use of higher compression heads on Bentleys, we are developing a scheme for using suction control in connection with the ignition advance to enable the accelerator pedal to be used on a higher compression head with the same freedom as on the standard head without running into detonation, by retarding the ignition when the throttle is open. The effect of this can be demonstrated on the streamlined Bentley by suitably manipulating the hand control for the ignition advance. Given the successful application of this device, the only other objection we know of to the higher compression is the increased roughness of the engine which would no doubt not matter in special cases but would probably require the improved engine mounting which is being developed to render the effect smooth enough for standardisation with closed coachwork. E.{Mr Elliott - Chief Engineer} | ||