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).
Fuel consumption, engine performance with French petrol, cooling efficiency, and central lubrication.
| Identifier | ExFiles\Box 11\3\ 03-page170 | |
| Date | 8th July 1930 guessed | |
| -3- 6 to 6,5 pints for every 250 miles. This is whether the water boils or not. Re the question of the French petrol that we are using. We have found it very difficult to produce good all round running results. There has been considerable trouble in setting the carburetter correct for all conditions, and it is very susceptible to the water temperature, considerably more so than when using standard petrol. The detonations are considerably worse, but with no sign of any building up. Rm{William Robotham - Chief Engineer} remarks that we may be running with a weak mixture, but we have not been able to obtain more than 10 M.P.G. petrol consumption. This is not up to our standard, and we have been trying to improve it. However, we will try tests running definitely on the strong side and observe the results. It is quite noticeable, during an evening's run, when the air temperature has cooled down, that we do not get more than 85°C. water temperature. This we think is a clear proof that the cooling efficiency is not sufficient for high air temperatures. Re central lubrication. We find that OY's recommendation of using Vacuum 'A' oil for the central lubrication would be all right for Winter use, but for Summer use it is too thin. We have changed it to the engine oil 'BB'. This oil is thinner than what we use normally on our standard cars. G.W.H. | ||