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).
Diagnosing a high-pitched clicking noise from the valve gear at 1250 r.p.m.
| Identifier | WestWitteringFiles\S\March1928-May1928\ Scan183 | |
| Date | 1st May 1928 guessed | |
| contd :- -2- full lift and choc-a-bloc. The collars were then turned back and the outers were then made .075" longer. Another complaint with these valve springs was that at a speed of 1250 r.p.m. a loud high-pitched clicking noise was set up from the valve gear. This noise was only detectable at that speed, and vanished just below and just above. It could be heard while running on the road, particularly on the overrun, and was noticed on 14-EX, 15-EX and 17-EX. Owing to the low bouncing speed, the double valve springs on 17-EX were changed to single ones and the clicking disappeared. We are unable to throw any light on this, and watching them through the Ashdown Rotoscope (a kind of mechanical oscilloscope) revealed nothing beyond the usual mild surging. HS{Lord Ernest Hives - Chair}/S.S. Tresilian. | ||