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).
Technical report discussing the issue of exhaust popping on the 'New Phantom' model.
| Identifier | ExFiles\Box 66\2\ scan0170 | |
| Date | 4th March 1926 | |
| COPY. To B.J. CWB8/DN4.3.26. "New PhantomCodename for PHANTOM I" popping in exhaust. I find it is impossible to prevent popping in the exhaust on "New PhantomCodename for PHANTOM Is" when over-running unless the throttle is kept shut. Even when kept shut there are times when it will pop, amounting to possibly 5% of the occasions when over-running. I have attributed the latter to a particle of grit having become temporarily stuck on the edge of the butterfly valve or on the induction pipe at the point where the butterfly sits, thus preventing it closing fully. The ball bearing governor control shaft is a definite improvement over the old plain bearing one, but it has not completely overcome the troubles. I am unable to explain why one should get popping with a small opening of the governor control and not when this is fully closed, because if one is travelling at any time at a speed greater than that corresponding to the position of the governor lever on the control column with the accelerator pedal released, the throttle should be fully shut. I agree that it does seem unreasonable to expect a driver to have to run to Town or in traffic, with his governor control fully closed, as it is very easy to forget to open this on every occasion before the car comes to a stop and so it is very easy to stop the engine on these occasions. The whole control of the carburetter is nothing like so regular in its action as that of the "Silver Ghost". CWB. | ||