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).
Investigation into the causes of a high-power engine running on after being switched off.
| Identifier | ExFiles\Box 124\2\ scan0029 | |
| Date | 29th January 1940 | |
| To Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} from Rm.{William Robotham - Chief Engineer} c. EV.{Ivan Evernden - coachwork} c. Jnr.{Charles L. Jenner} c. Rm{William Robotham - Chief Engineer}/PD. HUNTING AFTER SWITCHING OFF. HIGH POWER ENGINE. During the week-end under the abnormal snow conditions it was necessary to indulge in a good deal of full throttle second speed work at low engine speeds. Under these circumstances the coolant temperature rose to 90°C and it was observed that after 15 or 20 minutes of such work the engine would continue to run quite a long period after switching off. This is a repetition of the trouble which we had in the early days with high power engines and which was largely cured by modifications to the throat on the head. The trouble may only occur due to any of the following factors:- (1) High coolant temperature. (2) Ethylene Glycol in the system. (3) Insufficient coolant circulation at low speeds. (4) Pool petrol. (5) Unsuitable sparking plugs. (6) Deletion of the salt cooled exhaust valves. We should like an investigation to be undertaken immediately to find what effect these various factors have on running after switching off under the conditions mentioned. Rm.{William Robotham - Chief Engineer} | ||