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).
To F.H. Royce discussing different types of spark plugs and their performance.
| Identifier | ExFiles\Box 33\3\ Scan066 | |
| Date | 22th May 1920 | |
| OY3/G22.5.20. May 22nd.1920. To Mr. F.H. Royce - 2 I brought over samples of both of these types, which I believe you probably have at Chichester. There is no claim to any special design in these plugs except the fact of using a porcelain insulator of exceptionally high strength and resistance to change of temperature, with a large insulating surface inside the plug which gets hot enough to burn off accumulative carbon. For Ford cars, the Flint Champion makes a plug having a special rib internal insulator, which is intended to get especially hot on the projecting ribs so as to burn off accumulative oil. Mr. Caswell has used several thousands of the Toledo Metric Regular plugs and considers it to be one of the best plugs made in the United States. So far as we have discovered, the other plugs avail-able consist of trick designs of no special virtue. Mr. Belnap, in his many years of motoring in this country and Canada, has always found that one of the two Champion plugs give the best results. This in spite of the fact that they are quite cheap, being only one-third of the Herz and other similar plugs. If Mr. Caswell's tests on the new Metric Regular prove satisfactory, we will send a large batch to Mr. Hives for tests; and if not, will send the other two, namely, Flint and Toledo old type of plugs. The possibilities of the future are - SOW(H)W (21-4-21 9/SK19) Contd. | ||