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).
Report diagnosing valve noise on a Phantom II, caused by non-square valve springs causing the spring to rub.
| Identifier | ExFiles\Box 47\2\ Scan395 | |
| Date | 10th November 1930 | |
| 10.11.30. Re -> PHANTOM II VALVE SPRINGS. We have had considerable trouble in satisfying an owner who complained of valve noise at 40 to 45 m.p.h. This was definitely caused by the period of the spring at this speed and although every known remedy was tried, the noise still remained. I eventually traced it to the spring coils hitting the top of the cone of the bottom spring washer during the spring period. The reason why in this case, the trouble was caused was due to the present method of making the ends of the springs not square, which places the load on the bottom washer on one side only with the clearance allowed on the spigot of same, makes the bottom washer tilt over, bringing the top portion in contact with the spring coils, the felt pad beds in to this position. This was definitely proved on this particular car as when first fitted up the noise was not there, but after approx. 50 or 60 miles it came on as before. The sketch shows what happens SPRING RUBS HERE | ||