Cause of throttle sticking in 4¼ Litre Bentley carburetter controls.
| Identifier | ExFiles\Box 103\5\ scan0192 | |
| Date | 21th October 1937 | |
| File Copy. To BY. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /GWH. {George W. Hancock - Head Chateauroux} c. to Rm. {William Robotham - Chief Engineer} Rm {William Robotham - Chief Engineer} /GAW.16/N.21.10.37. ------------------- 4¼ Litre Bentley - Carburetter Controls - Throttle Sticking. ------------------- We have come across a further cause of the sticking of the S.U. throttle butterfly, due to the control spindle connecting the two carburetters. With the aid of the enclosed sketch, you will see how this comes about. The two carburetters are at fixed centres, the butterfly spindles being linked up by the serrated control spindle. There will be a minimum and maximum dimension if the length between the serrations of the coupling shaft A. {Mr Adams} and with throttles closed of C. We find that in some cases the dimension of C. is less than that of A. {Mr Adams} which places a binding effect on the butterfly valve in the closed position which causes sticking. With the butterfly valve open there is a free movement of .125 total. This does not want confusing with the closed position. If the serrations of the spindle A. {Mr Adams} are increased in depth approximately another .010" the trouble would be overcome. There is a Depot job which can bring about the binding of a similar nature. When the butterfly valve is removed from the throttle spindle for cleaning the carbon away, it is possible for the throttle spindle to be moved inwards lessening the dimension of C. This comes about through the large diameter of the holes in the butterfly valve which are made for the alignment of the butterfly valve B when setting closed. The increased depth of the serrations would take care of this, inadvertently closing in of the dim. of C. otherwise it means dismantling the carburetter and resetting the butterfly valve on its spindle. Rm {William Robotham - Chief Engineer} /GWH. {George W. Hancock - Head Chateauroux} | ||
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).