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).
Performance of spark plugs and magnetos, including customer feedback.
| Identifier | ExFiles\Box 47\1\ Scan027 | |
| Date | 11th March 1920 | |
| -2- Memo. No. 1963. "be made of an unsuitable metal which oxidises quickly and deeply and the internal resistance of the plug thus increases. The hotter the plug the greater this resistance hence the missing particularly when the engine is hot which we both experienced. Again the Bosch porcelain has always been acknowledged better than ours and in fact I believe in actual insulation tests it has been proved equal to or better than mica. I have had trouble with Lodge plugs before on both pre-war and post-war cars. I still think the Watford magneto inferior to the pre-war Bosch and I consider it is only just up to its work at any speed below 1000 revs. I believe also that a Bosch magneto would have sufficient reserve of energy to fire my faulty Lodge plugs. I have had another slight mishap. I found the battery ignition misfiring and discovered the platinum points on the L.T. contact breaker burnt almost completely away. The condenser in the aluminium cover had been firing across to one of the long securing bolts. I have slipped mica tubes over these as they are far too close to the condenser even though the corners are grooved out. The condenser was undamaged and the ignition is now perfect again. I am enclosing a letter from Ashley Abraham brother of my friend at Keswick which will put your mind at rest perhaps?! I would'nt exchange my 1914 car for 29-TW at any price. I thought my old car perfect I know my new one has achieved the impossible and is more than perfect. She is far more lively, the springing is better and I think even greater silence and smoothness all round has been achieved in spite of the extra power of the engine. She is a mechanical treat to one who has been brought up on machinery from infancy and motor cars since 1898. I should like to demonstrate the Bosch plugs if you are round my way any time. I hope they wont disappoint me and fall off in efficiency in use. If they are up to pre-war Bosch standard they wont. Yours sincerely, GEOFFREY SUMMERS." FRS. | ||