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).
Valve troubles in post-war cars, specifically addressing excessive wear, burnt valves, and potential causes.
| Identifier | ExFiles\Box 74\3\ scan0319 | |
| Date | 1st June 1922 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c.c. to OJ. c.c. to I. c.c. to Da.{Bernard Day - Chassis Design} c.c. to Ev.{Ivan Evernden - coachwork} c.c. to EP.{G. Eric Platford - Chief Quality Engineer} c.c. to Hm.{Capt. W. Hallam - Head Repairs} X4432 HS{Lord Ernest Hives - Chair}4/T1. 6. 22. VALVE TROUBLES ON POST WAR CARS. X4432 X3315 X4226 Valve troubles on post war cars consist of excessive wear of the valve and valve guides and an occasional burnt valve. As regards the burnt valve, from the appearance of them we should say that it was caused by pre-ignition. It, may, however, be caused by a crack originally in the valve. We have occasionally found valves with a radial crack which opens up when the valve in in use. The worst trouble is undoubtedly the wear of the valves and valve guides which entirely spoils the slow running of the car. We have seen one sample where the wear has been tremendous which has worn as much as .050". The wear has been caused by the valve being tilted over this is shown by the way in which the wear has taken place. The difference between the pre-war and post-war valves is that the valve lift has been increased from .300" to .400" on the inlet and .350" to .400" on the exhaust; the material has been changed from nickel steel to chromium steel. We had troubles with pre-war valves and guides wearing but not to the same degree. We have been able to trace a number of worn valves and guides to the fact that the valve springs were badly made. The valve springs were out of square so that they | ||