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).
The unsatisfactory performance and various troubles experienced with Lodge ignition plugs during testing.
| Identifier | ExFiles\Box 79\1\ scan0055 | |
| Date | 25th March 1915 guessed | |
| Re Lodge Ignition Plugs. Na.{Mr Nadin} EP{G. Eric Platford - Chief Quality Engineer}18/L24315. As previously reported, these plugs have not been entirely satisfactory on cars on test. The following are troubles which we are experiencing with same ;- 1. A tendency for pre-ignition, also self ignition, the engine failing to stop when the ignition is switched off after a hard run. 2. The gaps appear to vary when running. 3. Although at first, the plugs give very good results as regards slow running, this unfortunately, is not maintained and after a good thrashing the slow running is poor, which can be rectified by taking the plug out and cleaning out the electrodes. 4. The plugs are awkward to clean. 5. We have had cases in which the porcelain has cracked and also there is a tendency for leakage to take place as regards the gas passing the plug, either on the internal or external joint of the porcelain. From our experiments with ignition plugs, it appears that these failures are caused by the porcelain which is being used being a bad conductor of heat, allowing the centre point to overheat and also the electrodes to oxidise, such as was experienced with the Pognon type of plug. There certainly appear to have been various types of porcelain used for these plugs and the | ||