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).
Providing diagnostic advice for poor vehicle acceleration, focusing on mixture settings and ignition timing.
| Identifier | Morton\M13.1\ img011 | |
| Date | 3rd September 1920 | |
| X.3036 COPY. R phil To Hd{Mr Hayward/Mr Huddy} from R.{Sir Henry Royce} Copy to CJ. " " Pn.{Mr Northey} " " EP.{G. Eric Platford - Chief Quality Engineer} " " Hs.{Lord Ernest Hives - Chair} " " Cy. " " Gae. " " Sa. X.3922 RL/G3.9.20. Ref. Hanbury's Trials car X 3056 RE WANT OF ACCELERATION. Sorry to hear your car is not good for acceleration compared with others. If cause cannot be found by driver, ask London Repair Dept., failing these, Derby experts, and failing these, bring it to me. I should look for the following - Mixture wrong, probably low speed jet too strong, giving a very strong mixture before getting to high speed, try weaker low speed jet, and stronger high speed, keep regulation so that one can get sufficient strength for starting on cold morning. This is best done by arranging for the hand control so that it can only just get the mixture definitely weak enough in the extreme weak position when the engine is hot, with well advanced ignition, so that one can take advantage of the whole range of control we give. My impression is that we get best running and best consumption when the low speed jet is relatively slightly weaker than the high speed. Supposing then it is not carburation, and the engine is warm enough - Look if either ignition is too far advanced, because it is said that acceleration is good after reaching a certain speed - suggest too early an ignition at slow speeds. Contd. | ||