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 on post-war cars, including excessive wear on valves and guides, and burnt valves.
| Identifier | ExFiles\Box 76\4\ scan0241 | |
| Date | 1st June 1922 | |
| To R.{Sir Henry Royce} from Hs.{Lord Ernest Hives - Chair} c. to CJ. c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Sy. c. to Ep.{G. Eric Platford - Chief Quality Engineer} c. to Ha. X3315 (6 Hs{Lord Ernest Hives - Chair}4/T1.6.22. X4482 X4226 X3315 VALVE TROUBLES ON POST WAR CARS. Valve troubles on post-war cars consist of excessive wear of the valves and valve guides and an occasionally burnt valve. As regards the burnt valve, from the appearance of them we should say that it was caused by preignition. 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 is 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 pulled | ||