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 to The Robinhood Engineering Works Ltd. regarding issues with sooted K.L.G. R4 sparking plugs.
| Identifier | ExFiles\Box 58\3\ Scan011 | |
| Date | 11th October 1919 | |
| R H 235 A (100 T) (S F.{Mr Friese} 575. 16-4-19) G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 2354. X.1918e. EH2/LG 11th. Oct. 1919. The Robinhood Engineering Works Ltd., Putney Vale, London. S.W.15. Dear Sirs, We are not entirely satisfied with the K.L.G. R4 type of sparking plug. The chief complaint we have against it is that when it becomes sooted, the spark jumps across the inside at the top. This is a rather serious complaint because it is very difficult for the ordinary Owner or driver to realise what is going on. If the plug is tested outside, the spark jumps across the points normally; it is only when running with a weak mixture or full compression picking up, that the mis-firing occurs. We think that the trouble is due to the mica insulation keeping too cool and that it never gets hot enough to burn off the soot or carbon which collects. We have taken new plugs and tried them sparking under air pressure with the normal gap. When new, most of them are alright up to 90 or 100 lbs, but after they have been run on the car for 30 or 40 miles, they will jump across inside at 30 to 40 lbs. pressure. We should be greatly obliged for your views on this matter. Yours faithfully, | ||