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).
Cylinder wear caused by strong fuel mixtures from S.U. carburettors during cold starts.
| Identifier | ExFiles\Box 149\4\ scan0179 | |
| Date | 6th February 1937 | |
| H13 .1263 25 RUE GIDE. LEVALLOIS-PERRET. Seine. France. Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}/7/JAB. 6th February 1937. To. Rm.{William Robotham - Chief Engineer} I have received your memo. Rm{William Robotham - Chief Engineer}/I5/R.4.2.37. With regard to the mixture controls on the Bentley, I did not write with the intention of comparing the starting device with Phantom I & II. It was solely from a point of cylinder wear. It is fairly common knowledge that 2 S.U. carburetters fitted to an engine cause more cylinder wear than other makes of carburetters, and it is believed, that it is chiefly due to the strangling effect when starting up from cold which is the cause. Kingsbury have pointed out to many chauffers when they have been starting up the car, the leaving on of the strong mixture for too long a period with the consequent result, that the strong mixture was washing off the lubrication off the cylinder walls. It was with this view that I wrote suggesting the spring loaded controls, but leaving sufficient notches to keep the engine running under the conditions you mentioned, such as manipulating the car in the garage before getting on the road it would therefore not be necessary to have one hand on the control and one hand on the steering wheel. ---------- Dixon Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} You might challenge skinner about this. Have you tackled him on the cost of the additional Piu petrol pump yet? 2/18-0 Rm{William Robotham - Chief Engineer} | ||