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 the AC-Sphinx Sparking Plug Co. Ltd. concerning misfiring of motor car plugs and the benefits of their ceramic plugs.
| Identifier | ExFiles\Box 163\5\ img046 | |
| Date | 10th July 1936 | |
| TELEGRAMS: SPHINX, DUNSTABLE THE AC-SPHINX SPARKING PLUG Co. LTD. DIRECTORS: N. F.{Mr Friese} STOCKBRIDGE, W. O.{Mr Oldham} KENNINGTON, C. J.{Mr Johnson W.M.} BARTLETT. DUNSTABLE BEDFORDSHIRE OUR REF. NFS/KB. YOUR REF. Ns{Norman Scott}/wst.12/JH Messrs. Rolls-Royce Ltd. DERBY. For the attention of Mr. H.E.West. Dear Mr. West, I have your letter of the 9th instant concerning misfiring of motor car plugs. It is very difficult without seeing the plug to give you an opinion as to whether the misfiring was due to simple carbon deposit or to the condition of the insulator due to lead attack. In my opinion the situation is that if you fit a Bentley with a mica plug having an internal insulation length sufficient to obviate carbon deposit on ordinary town driving, such a plug would be quite unsuitable for high speed work - firstly due to pre-ignition that will arise and secondly owing to lead attack to which such a long insulator nose will be prone. With our ceramic plug, we are better placed as regards both those aspects; we can so shape the insulator nose that it virtually burns away any carbon deposit even at town driving speeds - while at high speeds, firstly the heat conductivity of our new material is such that it will obviate preignition, and secondly the surface of the insulator is, as you know, not prone to lead attack. I ought to be able to prove the above to you completely, when we send you the two sets of plugs which we are making for the Bentley type. With regard to the delivery of the two sets of plugs for the...... (Cont'd) MAKERS OF AC SPARKING PLUGS - AC AIR CLEANERS - AC PETROL PUMPS - AC PETROL GAUGER - AC OIL FILTERS - AC OIL GAUGES TELEPHONE: DUNSTABLE 360 PRIVATE BRANCH EXCHANGE. 86011 | ||