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).
Refinement of idling performance in high-power engines.
| Identifier | ExFiles\Box 159\5\ scan0155 | |
| Date | 4th March 1941 | |
| Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} from Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} Instructions to Shop 1373 Rm.{William Robotham - Chief Engineer}2/ML.4.3.41. IDLING - HIGH POWER ENGINES. Now that we have broken the back of the mechanical failures of the B.V. we have time to devote to refinement. We have had various degrees of idling on the cars we are running and we now really want to decide whether camshaft EX.33975 gives a satisfactory degree of slow running with a tappet clearance which is silent or not. It occurs to me that the test bed timing for this camshaft, of 9º before top dead centre, is rather early, and better idling may be obtained with half a tooth later setting. It is curious that long reach plugs do not improve the idling since the head we have turned down for roughness gives better slow running, and one of the few obvious differences between this and the head we are standardising is plug position. When we are considering slow running we should check up on pipe size, because if a very small induction pipe gives good idling, then the Duplex scheme possesses one basic advantage. We know that the 8-cylinder mounting allows more vibrations to reach the passenger from any given degree of engine movement, and therefore perhaps it is better to work on a B.60 engine and compare the results obtained with the B.V. Personally, I have formed the opinion that 3.B.50. is very nearly up to Bentley standard, though is hardly good enough for Rolls Royce. We still have some experiments to make with the balance hole in the centre of the pipe. - Continued - | ||