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 clarifying issues with spark plug deposit build-up and discussing ceramic versus mica plug types.
| Identifier | ExFiles\Box 150\1\ scan0252 | |
| Date | 1st December 1936 | |
| CABLEGRAMS: ETHYLPORT, LONDON. TELEGRAMS: ETHYLPORT, SOWEST. RM {William Robotham - Chief Engineer} 1282 ETHYL EXPORT CORPORATION Incorporated in the State of Delaware, U. S. A. {Mr Adams} 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 December, 1936. H. {Arthur M. Hanbury - Head Complaints} West Esq., Experimental Department, Messrs. Rolls-Royce Ltd., Nightingale Road, DERBY. Dear West, Very many thanks for yours of the 30th November. I am afraid I did not make myself clear in my letter to Rm. {William Robotham - Chief Engineer} and I agree with you that, so far as ordinary petrol is concerned, wet plugs do not matter. What I intended to infer however was that due to the swamping of the plugs with petrol and the subsequent drying off of the fuel some lead deposit would be left behind; and the more starts one gave to an engine under these conditions the greater the rate of deposit built up. With reference to the last paragraph - the plugs used by the manufacturers concerned were both Ceramic and mica. I would say two thirds Ceramic and one third mica. In the case of those manufacturers using mica plugs the cars, such as Rovers, are of the high duty type, and we have no record of any epidemic, such as you are now suffering, from any of these companies. I do think it worth while however, to try a warmer running plug to see whether it gives improved results, and also to ask the makers of some Ceramic plugs, such as A.C. or Champions, whether they cannot offer you something which would be suitable. I would repeat that should you like me to come up to Derby at any time I would be glad to do so. With kind regards, Yours sincerely, F R Banks FRB/FH | ||