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).
Comparing the quietness and performance of two different valve springs, E.78071 and E.70442.
| Identifier | ExFiles\Box 56\2\ Scan103 | |
| Date | 25th September 1930 | |
| X290 To Ev.{Ivan Evernden - coachwork} from Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} Hs{Lord Ernest Hives - Chair}/GWHL/AD25.9.30. RE - VALVE SPRINGS. We have been testing out for quietness and general behaviour the two types of valve springs E.78071 and E.70442. The spring E.78071 which is the original semi closed type is definitely quieter irrespective of the fit of the spigot. With a close fit on the spigots of the bottom and top washers there is no difference for quietness with either type of spring. We have not run sufficient mileage to determine whether there is any difference in the life of the two types of springs. Both types have been run at high speed for approximately 500 miles and no defects have arisen. Hs{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} | ||