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).
Page discussing engine performance issues related to fuel distribution, throttle adjustment, and fuel quality.
| Identifier | ExFiles\Box 50\3\ Scan023 | |
| Date | 24th February 1921 | |
| Contd. -3- Hsl/LG24.2.21. distribution caused by the boss in the throttle. The piece of rod which we screw in has two flats in it and one can play about with the adjustment of this projection and vary the distribution of the engine. A great number of throttles have been corrected by this means now and have proved successful. It is surprising with some of the bad throttles how very bad the distribution is. Some cylinders throw out black smoke due to excessive petrol - others are too weak. The effect on the road is that the car will not climb hills at low speeds on top gear - secondly, that if a car is run for a short time full throttle low speeds, it will misfire when picking up. With a good throttle and good petrol, the distribution on our engine at normal temperatures is very good. We know very well in the past that the distribution of a 40/50 engine has been remarkable. One of the best tests for distribution is the range that the mixture can be weakened and the power to fall away without popping or missing occurring. We know very well that that has been a feature on our cars. "We have carried out a number of tests and find that it is no use adding hot spots and extra heat to the carburetter or pipe unless the distribution under cold conditions is good. We have proved that hot spots and heated induction pipes improve an engine which has bad distribution but we cannot get the same degree of improvement by adding heat as we can by correcting the throttle. The lower grade of gasoline makes the trouble caused by a bad throttle much worse. This is proved by the fact that cars identical to those being Contd. | ||