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).
Faults found in an 8-cylinder carburation system, including sudden opening, hesitation, and sticking choke.
| Identifier | ExFiles\Box 109\4\ scan0205 | |
| Date | 10th August 1939 | |
| 66a To. Rm{William Robotham - Chief Engineer}? [struck through] c. Rm{William Robotham - Chief Engineer}/ MGD. [struck through] c. Rm{William Robotham - Chief Engineer}/ FJS. [struck through] c. Rm{William Robotham - Chief Engineer}/ CTS.{C. Trot Salt - Carburation} [struck through] c. Rm{William Robotham - Chief Engineer}/ Gr.{George Ratcliffe} CHATEAUROUX. 3/10.8.39. 30.G.VII. 8-CYL. CARBURATION. There are three faults under consideration:- 1) Sudden initial opening. 2) Hesitation on light throttle. 3) Sticking choke 1) The graph enclosed shows the opening when set up to EGD.1376, our improved opening as tested and reported upon, and the B.V. opening for comparison. We appreciate that the Stromberg and S.U. butterfly characteristics are different, but this difference is not apparent to the driver, in fact with the violent acceleration of the 8-cyl. unit, we want as gentle a throttle opening as we can possibly get. We are returning the drawing EGD.1376 with the alterations marked in. We have turned the output lever on the countershaft in the frame through 30° and shortened its rod. The output lever on the countershaft on the dash has been turned through 33° and its rod shortened. The lost movement (or increased pedal travel, whichever way you look at it) can be corrected either by lengthening the output lever on the countershaft on the dash to 2.125", or by reversing the bell crank lever at the top of the dash. Either of these give the curve shown. The hand throttle pick-up has to be modified slightly. 2) The hesitation appears to be a function of throttle position and not speed, and will occur at any speed from 10 to 30 m.p.h. if the throttle is opened very gently either from a closed or from slightly open position. | ||