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).
Proposing stronger valve springs to prevent jumping at increased engine speeds, with specific load and tempering requirements.
| Identifier | ExFiles\Box 80\3\ scan0171 | |
| Date | 14th October 1913 | |
| COPY. V290 COPY. R2/P 14.10.13. Re Stronger Valve Springs for increased speed. X.449 To E.{Mr Elliott - Chief Engineer} from R.{Sir Henry Royce} Copy to Wor.{Arthur Wormald - General Works Manager} " " Hives. " " J.{Mr Johnson W.M.} I propose that the normal load shall be 55 lbs plus or minus 2 lbs. I should like them to be Derby hardened and tempered, and suitable for engine speed up to 2500 revs. without jumping, but doubtful at still higher speed and must certainly jump at 2750. Please fit or send such spring for 2704. My desire is that the valve shall not jump the cam when driving the car at high speed or on low gears on hills, but that if the engine is wilfully raced without load that the valves shall make a noise before a dangerous speed is reached. London to Edinburgh engines should have such springs as quickly as possible. It has been demonstrated that jumping the cams is the chief cause of broken valve springs. Mr Nadin and I are making a list of experiments re tempering such springs. F.H.R. | ||