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 from Ethyl Export Corporation discussing spark plug issues, deposits from leaded fuel, and potential solutions.
| Identifier | ExFiles\Box 150\1\ scan0187 | |
| Date | 1st September 1936 | |
| CABLEGRAMS: ETHYLPORT, LONDON. WST. X1282. TELEGRAMS: ETHYLPORT, SOWEST. ETHYL EXPORT CORPORATION Incorporated in the State of Delaware, U.S.A. with limited liability. THAMES HOUSE, MILLBANK LONDON, S.W.1 Telephone: VICTORIA 1441 Head Office: 135 EAST 42ND STREET NEW YORK, U.S.A 1st September, 1936. W. A. {Mr Adams} Robotham Esq., Experimental Department, Messrs. Rolls-Royce Ltd., Nightingale Road, DERBY. Dear Rm. {William Robotham - Chief Engineer} , I wish to acknowledge, with thanks, receipt of your letter of the 31st August addressed to Fossett. As a matter of fact, when I made my hurried visit to you before taking my holiday Fossett was on a job for us abroad and consequently I was unable to give him the full history of your plug complaint and he was not aware of the real nature of the problem. The plugs sent to us by you while I was away were very thoroughly tested and the deposits investigated, and everything points to the plugs themselves running rather on the cool side. I agree, from the data you gave me and that contained in your letter, that the plugs appear to have been the cause of the trouble, and that this occurs with leaded fuel and not with any other. Since the nature of the deposits indicates that the plugs were running on the cool side and the deposits themselves, under low temperature conditions, are reasonably good electrical insulators, I am of the opinion that the trouble may be caused by condensed moisture which is either picked up by the deposits or settles on them, causing a break down in resistance. If this is so, would it be possible for you to get K.L.G. or Lodge to supply a somewhat hotter running plug, but of course one which will not give rise to pre-ignition. I appreciate that this is easier said than done, but I think it would be worthwhile experimenting with plugs having different heat characteristics and longer or shorter insulators. Have you had a chance to try out any of the Champion types? With further reference to the set of plugs you sent us, we thought that it would save time to do physical and chemical tests here to satisfy ourselves as to the general condition of the plugs and to give you a quick answer, but since this investigation has not apparently helped us much I would like, if possible, to have another set of defective plugs in | ||