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).
Internal memorandum discussing the performance, cleaning, and selection of various spark plugs.
| Identifier | WestWitteringFiles\E\September1920\ Scan13 | |
| Date | 1st September 1920 | |
| To HS.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} -2- R5/G10/9/20 Contd. Lodge or K.L.G. or the four-pointed Bosch, in which the central electrode could be taken out and the surface of the stoneware or mica, cleaned properly, and conveniently. It occurs to me that if the mica can be used in the way that the Lodge people are now supplying plugs, then one would think that it is quite possible for the centre part of the plug to be removable for cleaning. My impression is that we can have two things, one is a plug which is self-cleaning like the old all-stoneware Lodge, or one which can be easily taken to pieces for cleaning, like some of the Lodge, K.L.G. and four-pointed Bosch. I should be glad if you and Mr. Platford would make certain whether the plugs we are sending out are the best that we can obtain, and that they are likely to give entire satisfaction. My impression, which I hope is wrong and which is not founded on very much experience, is that it is neither convenient to clean, nor self-cleaning, and is quite easily sooted up. One thinks that with our car engine we have little risk of oiling plugs, and in car service very little risk of over-heated plugs, but we certainly have difficulties of very slight deposits of soot spoiling the ignition, and especially affecting it at slow speeds. X.3763 I have just been over 1 EX. engine and find that it appears in excellent condition, except for some reason or other which I have not yet determined, there is a distinct revolution variation in the exhaust at very slow speeds, especially noticeable on the battery ignition, when this is retarded. I am going (Contd.) | ||