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).
Investigation into spark plug fouling issues on a Rolls Bentley, and subsequent testing of different spark plugs and a Delco ignition system.
| Identifier | ExFiles\Box 146\5\ scan0309 | |
| Date | 4th March 1940 | |
| Letter fr SR. c.Managing Director Secretary E.P. REPORT NO. 7138/39/40/41 4.3.40 ROLLS ROYCE DERBY Research Engineer : Mr. Robotham Chief Asst. Mr. Childs (Auto) Mr. West (Aero) Called above at their request. Saw Mr. Childs and investigated his complaints and find this report has arisen in France on the LB-8 in Rolls Bentley. It is a case of fouling after approximately 2,000 miles and they admit that the poor quality fuel now being used is in a large measure responsible, but they wish our co-operation in overcoming this difficulty. In the first place, Mr. Childs is practically 100% Champion owing to the results he has obtained from various tests, and on most of the reports he showed me there was a footnote to the effect that with either N-8 or LB-8 improvement was shown. These reports comprised of Champion K.L.G. Corundite and Lodge Sintox, tested comparatively, and he remarked that Mr. Rowbotham was being forced to recognise these facts. I discussed the possibility of fitting L-10 for test, inspected cylinder head and to carry out these tests, a slight modification must be made to allow the shorter barrel length to be used. Mr. Childs is prepared to do this and as Mr. Rowbotham also approved, I left with him twelve L-10 for test. In connection with Mr. Child's test a query has arisen which may have some bearing on plug failure at the 2,000 marks, which as follows : EXPERIMENTAL TEST REPORT Car was run for 2,000 miles and slight missing was experienced. Plugs removed. After investigation replaced with new set. Missing was eliminated. This test was continued over 12.000 miles in runs of 2,000 approximately and in each test same symptoms were experienced. Insulators reported to be in excellent condition and no sign of burning on electrodes was apparent. A Delco Distributor was fitted with extra boost coil and in all cases the missing at 2,000 miles was cured. Mr. Childs agreed that obviously the correct thing to do was to fit the Delco ignition. They however investigated further with plugs and when missing occurred at usual figure, the plugs were removed apparently OK. a | ||