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).
The development of a high-power cylinder head, discussing valve design and performance.
| Identifier | ExFiles\Box 134\1\ scan0051 | |
| Date | 14th December 1937 | |
| By.{R.W. Bailey - Chief Engineer} from Rm.{William Robotham - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Hy{Tom Haldenby - Plant Engineer}/Jnr.{Charles L. Jenner} c. Hm{Capt. W. Hallam - Head Repairs}/Swdl.{Len H. Swindell} HIGH POWER HEAD. The attached report shows the recent development work that has been done on the single cylinder O.H. Inlet side valve exhaust engine. The drop occasioned by arranging the inlet valve so that it will not hit the piston if it sticks open is measurable but not very serious. The low speed M.E.P. for a given degree of detonation is still considerably better than our present head. The outstanding design point that requires clearing up, is how to get the required 380 exhaust valve lift with an inexpensive tappet. We believe that the latest 16 cyl. Cadillac gives some indication that this can be done on a plain mushroom type tappet. If the results obtained by Jaguar with their twin exhaust systems is, as we think, possibly reasonably correct (they claim only 3 B.H.P. loss at 4000 R.P.M.), we ought to be able to take full advantage of the increased B.M.E.P. available with this engine which amounts to 20% at 4,000 R.P.M. We hope, from a bearing point of view, that it will not be necessary to run our new unit much above 4,000 R.P.M. for the time being at any rate. Rm.{William Robotham - Chief Engineer} | ||