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).
Development and testing of various sparking plugs for different car engines.
| Identifier | ExFiles\Box 162\3\ img204 | |
| Date | 22th August 1940 | |
| Plugs - S General At the moment the most suitable cars for plug testing are 1-R-8, 9-B-V and 4-B-80. To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/RC.{R. Childs} c. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} Rm{William Robotham - Chief Engineer}/RC.{R. Childs}1/SW.22.8.40. DR/MR Sparking Plugs. During the last few months, we have had very little opportunity for sparking plug development. Firstly, both KLG and Lodge, are too busy with Aero work to carry out development work on the car side. Secondly, the conditions under which our engines are working, do not provide very accurate information. At the moment the Champion "N.8", is the best plug for the CI engine; until recently we were fitting the Champion LB.8 to the B.60 engine, but now consider that the longer reach of the "N.8" is an advantage with regard to the firing of weak mixtures. The KLG.FE.30X, as used on the P.111 engines, have been tried on 9-B-V, but were turned down, since, with their use, the engine was inclined to go on firing for a short period after the ignition had been switched off. The fitting of Champion N.8 plugs cured this trouble. However, it should be mentioned, that the same plugs - FE.30X - are fitted to 4-B-50 (B.80 No.4) and are giving no trouble. For the Bentley V engine, the Champion LB.8, is the best plug for all round conditions. The KLG.FLB.30X - standard Wraith - is a close second, and slightly better for town con-ditions. For the Wraith, the KLG.FLB.30X, is the most suitable. In this case the Champion LB.8 runs a shade too cool. The Lodge Co., have given us an improved type of plug designated "741". We have tried these out in 1-R-1 without success. We would like to try these out on a B.60, since 1-R-1 is not a suitable car for plug testing. The distribution on this car is poor, and in each reported case of missing, the front three plugs were perfect, whereas the rear three were sooted up. The soot provides a leak, and thus causes missing. We have tried numerous types of AC plugs without success. P.T.O. | ||