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).
Tappet wear on the Spectre Valve Gear and proposing a spring redesign.
| Identifier | ExFiles\Box 96\2\ scan0022 | |
| Date | 24th January 1935 | |
| Ll. Smith. x357 SECRET. To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} from E.{Mr Elliott - Chief Engineer} E.2/HP.24.1.35. C. RHC.{R. H. Coverley - Production Engineer} E/JNR.{Charles L. Jenner} E/DSN. SpectreCodename for Phantom III Valve Gear. After further thought about the SpectreCodename for Phantom III tappet trouble, I believe it is evident that the wear is simply due to excessive load when the tappet is on the base circle. From E/JNR{Charles L. Jenner}'s recent memo you will see this load is 9 lbs. In accordance with the spring specified on LeC.3849. It seems to me we have got to get rid of this base circle load and the valve gear will be alright. I have looked into making the tappet stop within 2 thou. of the base circle but fear this would introduce too much complication, and that the proper treatment is to re-design the spring to give from nothing to 2 lbs. load in the base circle position. In the meantime, I should like, if you are in agreement, to have a test run with a new set of tappets with no tappet springs in at all, and if these are alright we can follow up with the re-designed springs. E.{Mr Elliott - Chief Engineer} | ||