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 slow running and poor idling issues, detailing modifications and test results.
| Identifier | ExFiles\Box 101\3\ scan0071 | |
| Date | 5th June 1937 | |
| Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. to E.{Mr Elliott - Chief Engineer} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}7/AP.5.6.37 25/30. SLOW RUNNING. The following are the results of a visit to Cricklewood on the above complaints in which two cars were tackled; Lord Swinton and R.C.Sheriff. As received, the former car had atrocious idling and all the available things for improvement were fitted including:- (1) New governor whereby the ignition can be set at T.D.C. instead of the usual 13° before T.D.C. full advance on the hand control. The hand control range was also shortened (similar to scheme LeC.5697) so that at full retard the timing is the same as standard. (2) Improved type of R.R. coil (Wraith) with ballast resistance to suit. (3) K.L.G. F.L.B.30.X. porcelain sparking plugs set at .025" gap. (4) Tappets set at .008" clearance. The idling on the first trial after warming up was excellent but after a good run on the road the idling had again gone erratic. The carburetter suction noise was uneven and gave the impression of over richening between periods of correct running at which time the engine would hunt. The carburetter was replaced by another which had been overhauled and this was appreciably better for even idling, though still not satisfactory. At this juncture the chauffeur arrived to take the car and he expressed the opinion that there was a definite improvement, despite this however, I was not pleased with the result. The new coil gave some improvement from idling misfires, but did not overcome it entirely. It was also noticeable that the replacement carburetter was more free from spitting in the silencer than on the original carburetter. The latter has been brought back to the Works for investigation in order to try and find why it is so bad for the uneven suction noise and spitting in the silencer. Based on the fact that an interchange of carburetters gives different results, points to variation in the idling feed and we are coming to the conclusion that there is interference between the various feeds which causes the uneven suction. continued | ||