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).
Investigation into the cause of engine rattles, focusing on the camshaft, crankshaft and timing gears.
| Identifier | ExFiles\Box 35\3\ scan 013 | |
| Date | 20th April 1920 | |
| Contd. -2- Hs{Lord Ernest Hives - Chair}3/LH{Mr Haworth}20.4.20. We have taken an engine which is free from rattles, we took the magneto off altogether so as to be free from any noise caused by the uneven turning of the magneto. We afterwards fitted a slack camshaft wheel. As soon as the slack camwheel was fitted we had rattles in the gears which could be damped out by applying a brake to the camshaft. We then tried having the camshaft wheel tight and arranging ample slack in the idler wheel, wheel for driving the battery ignition and pumps. We found on that side we could have considerable slack without causing any rattles. We found that the rattles (with a slack cam wheel) could only be heard at low speeds, at high speeds no distinct rattle could be noticed. Although we think the camshaft is the chief cause of the rattles, the crankshaft does enter into it, for instance, if we short one cylinder one can hear the effect of this in the noise of the timing gears. This is especially noticeable if there is no spring drive on the crankshaft. When running with a slack cam wheel we found that we could distinguish an uneven-ness in the rattle if we increased the spring pressure on one valve, which rather proves the noise does come from the camshaft. Hs.{Lord Ernest Hives - Chair} | ||