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 AC-SPHINX SPARKING PLUG CO. LTD discussing the performance of single vs three-point spark plugs.
| Identifier | ExFiles\Box 79\2\ scan0185 | |
| Date | 22th August 1925 | |
| Messrs. Rolls-Royce Ltd. 22nd August 1925 - 2 - Recent tests which we have carried out, however, indicate that a single firing point with welded negative pole is equal to, if not superior, in actual performance to a plug with three points wherein the three negative points comprise a washer which is held in the usual manner. The heavy type of central electrode ensures long life, the actual firing point being pure nickel inserted into a copper electrode. The plugs we are sending are entirely English construction throughout both as regards material and workmanship, and we hope that your test will enable you to consider placing your equipment business with us. These plugs have been continuously tested in our own 20 H.P. Rolls Royce car, and give excellent results, so we feel that we have some justification in bringing the matter to your notice. Should you require a further quantity so as to carry out simultaneous tests on your larger engines, we shall be very pleased to supply plugs entirely free of charge. Please accept the plugs we are sending with our compliments. Yours faithfully, THE AC-SPHINX SPARKING PLUG CO.LTD Director. 12-B-11 three point Plugs. (Under separate cover) P.S Previous correspondence on Sparking Plugs was ref. ROY{Sir Henry Royce}8/MG4.3.25 dated February 4th. | ||