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).
Cam and rocker head differences and proposals for quietening tappets on the Spectre engine.
| Identifier | ExFiles\Box 133\2\ scan0163 | |
| Date | 2nd July 1935 | |
| -2- Hs{Lord Ernest Hives - Chair}/Smth.12/KW. 2.7.35. The differences between the two heads are due to the fact that in one case the cam is above the rocker and in the other, below. With neither head do the clearances vary by more than .005, which is the same as on a Bentley immediately after starting up. We ought to have no difficulty in obtaining quiet tappets on the SpectreCodename for Phantom III without sacrificing either power or slow running, by putting a Bentley opening toe and a 20/25 closing toe on the existing cam forms and using an overhead camshaft. Hs{Lord Ernest Hives - Chair}/Smth. | ||