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).
Letter to The Lodge Sparking Plug Co. detailing test results of 4 special sparking plugs.
| Identifier | ExFiles\Box 79\1\ scan0103 | |
| Date | 24th June 1918 | |
| X 601 EH1/LG24618. 24th. June 1918. The Lodge Sparking Plug Co. Ltd., Rugby. Dear Sirs, For the attention of Mr. Lodge. We are returning to you 4 special Sparking Plugs which you sent to us for test. We ran these plugs in a standard engine under normal conditions, we found under that condition there was no pre-ignition, the Copper Centre Electrodes, however, worked loose, and whilst the engine was running, one could actually see them moving about. We then tried them on the special 3 Cylinder Test Engine to observe the point, but on neither type did the Centre Electrodes get red hot. Although we had tightened the Centre Electrodes up, it again worked loose. We then tried the plugs in a cylinder which was pre-igniting electrically, under this condition one of the insulators broke. It ran for some time before it broke so that there can be no question of sudden expansion. Under this condition the points did get red hot, we could not tell any difference in the two types. You will be able to judge by the colour of the terminal nuts, how hot the centre electrodes have been. Contd. | ||