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).
Engine head performance, comparing induction, valve sizes, and testing for Continental Units.
| Identifier | ExFiles\Box 93\4\ scan0078 | |
| Date | 7th October 1936 | |
| -2- An induction depression of 5" Hg. is an extraordinary high figure and if it is possible to bring this down to our normal Bentley and 25/30 H.P. figure of approximately 2- 2.5 Ins. Hg. by removing the restriction in the carburetter etc., we should appreciably increase the high speed power. This is to be one of the next jobs in connection with the development of the "Continental Units" One point which must not be overlooked in the comparison of the heads is that the valves in the 4 port head are; inlet 1.50 dia. exhaust 1.300" dia. against 1.45 and 1.25 respectively in the standard head. We have no comparison of power with valve size in any Phantom III head, but from experience on other engines we should say they would not be responsible for more than 8 B.H.P. of the gain. The actual heads tested, have been fitted into 32-EX for further road testing with regard to performance, carburation and slow running. On the test bed we could not detect any difference in slow running with either head. With regard to exhaust heating of the hot spot which was designed in conjunction with the 4 port head we have as stated in the memo. Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}5/KW.7.10.36. decided to continue with water heat for the present in view of the development required to bring exhaust heating to a production standard. Rm{William Robotham - Chief Engineer}/L.H.Swindall. | ||