Use of extra-long reach spark plugs and investigating ignition deterioration issues.
| Identifier | ExFiles\Box 127\4\ scan0190 | |
| Date | 8th March 1940 | |
| - 3 - Cont'd. {John DeLooze - Company Secretary} Rm {William Robotham - Chief Engineer} /CTS. {C. Trot Salt - Carburation} 5/ML.8.3.40. By fitting the extra-long reach plug, the points then come just clear of the wall of the combustion space proper. We should try these plugs for ourselves on our own latest cylinder heads. Rm {William Robotham - Chief Engineer} /EC should obtain suitable grades from A.C's. They have not experienced any ignition deterioration after mileage on a weak mixture car, because they have never run such a test, but they state that equivalent conditions are automatically produced by their customer's cars, and that there are no complaints. They do admit, however, that they have not been able to go into production with their weakest Experimental settings, due to inconsistencies; mainly concerned with the carburettor. Finally, it would seem that at the present time there is not sufficient information available to show which way we should go for any possible improvement from the ignition. But the main questions we require answering are as follows:- (1) If the deterioration of plug efficiency is due to leakage from accumulated deposit on either the points or the button or both; can this factor be varied by using a different grade of the same plug? (2) On a given plug, we say that this deterioration becomes objectionable at 2,500 miles; would this be overcome? by an increase in voltage. If so, would the cure be permanent? or, another way, would further deposition take place and thus in time produce an increased leakage in proportion to the extra voltage? - Continued - | ||
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).