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).
Potential causes for poor engine performance, including compression, fuel, and external drag factors.
| Identifier | ExFiles\Box 181\M13\M13.1\ img012 | |
| Date | 3rd September 1920 | |
| R.R. 109 (250?) (SD676 19-7-17) MP 18.865 Contd. -2- R1/G3.9.20. Supposing then alteration to timing of ignition makes no difference, we might suppose something was wrong with pistons or valves not holding their compressions. This is easily tested by judging a hot and cold engine at the starting handle. I like six excellently tight compressions. There seems only left that the valve timing may be too early, or the fuel bad. Here, we like a mixture of good benzol and petrol, and probably the present blended Shell is excellent for avoiding detonations in dirty engines. Do not forget that one little thing can spoil an otherwise excellent car. Also, beware of the extra drag of soft road and soft tyres, and heavy clumsy bodies of great windage. A good head wind will spoil one's impression of acceleration. R.{Sir Henry Royce} | ||