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).
Test report on chain oscillation during the test bed development of an overhead camshaft conversion for a 4 1/4-litre Bentley engine.
| Identifier | ExFiles\Box 113\5\ scan0175 | |
| Date | 5th December 1936 | |
| E.{Mr Elliott - Chief Engineer} from Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} c. to Hs.{Lord Ernest Hives - Chair} c. to Hy.{Tom Haldenby - Plant Engineer} c. to Da.{Bernard Day - Chassis Design} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}4/R.5.12.36. Overhead Camshaft Conversion on 4 1/4-litre Bentley. Further Test Bed Development following on the report Rm{William Robotham - Chief Engineer}/CTS{C. Trot Salt - Carburation}1/MJ.27.10.36. The Chain Drive. In the above report, it was stated that a period of oscillation takes place on the chain and tensioner, which came in at 1950 R.P.M. and went out at 2450 R.P.M. A series of tests have been carried out to determine the source of this period, and having done so, to either stop the period or prevent it from affecting the chain. On a closer examination of the chain in action, through a window in the front of the engine, it was found that two other periods existed lower down the speed range. These being quite apart from the main period mentioned above. Chain Oscillation. Test No.1. (1) 1300 RPM ) These are distinct periods, being short and (2) 1700 " ) sharp at the speeds stated (not extending over any range of speed.) They are not sever enough to overcome the tensioner, but on the driving side, the chain can be seen and heard hitting the fabroil block. On examination of this block, the chain is seen to have worn deep grooves. (3) 1950-2450. Full oscillation takes place over this speed range, completely overcoming the tensioner, which rattles very badly in the process. Fabroil Block Removed. Test No.2. (The periods are quoted at the speeds at which they come up in the speed range.) (1) 1100-1400 RPM. It is evident that the fabroil block was damping the chain movement, as the speed quoted for the first period was obviously the peak of this period. The oscillation is now very much worse, | ||