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).
Technical memorandum discussing ignition system issues, including spark plug gaps, suppressors, and coil/distributor screening.
| Identifier | ExFiles\Box 63\3\ scan0037 | |
| Date | 22th June 1934 | |
| -3- Ha/Ent.S/WHA.22.6.34. Cont'd.{John DeLooze - Company Secretary} in all probability due to slight variations which must occur in their susceptibility to excess cylinder head lubrication. Screening the wires, coil and distributor is a complicated and expensive procedure and usually involves the necessity of fitting a modified coil to deal with the extra capacity loading. Messrs.Lucas also inform us that the distributor sparking points wear much more rapidly due to the extra capacity involved in the H.T. load between the coil and distributor. The Americans who profess to experience no trouble with the fitting of suppressors use different sparking plugs i.e. Champion and A.C. both of which have ceramic insulators and entirely different shaped sparking plug electrodes. We do not consider that there is any difference in our coils to theirs as we have seen an 8 litre Bentley with Delco Remy ignition exhibit similar ignition trouble to that experienced at N. A way out of the difficulty would be to open out the spark plug gaps and if necessary increase the voltage of our coils. The best scheme of all is, we consider, to combine the coil and distributor in one screened unit similar to the one we fitted to the Kestrel aero engine and use screened cables or better still completely conduit the wires direct from the distributor. It seems wrong on principle to interfere with the spark energy and characteristics by the use of suppressors. If any deleterious effects can be eliminated with these suppressors by a suitable modification to the size and form of the plug electrodes, their inclusion in the ignition circuit should be an advantage in reducing sparking plug point erosion. | ||