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).
Letter to The Lodge Sparking Plug Co. regarding issues of pre-ignition and overheating found during a test of their Z.10 and Z.11 spark plugs.
| Identifier | ExFiles\Box 79\1\ scan0137 | |
| Date | 14th September 1918 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. X. 601. EHL/LG14918. 14th. Sept. 1918. The Lodge Sparking Plug Co. Ltd., RUGBY. Dear Sirs, For the attention of Mr. Lodge. We have run a doz. of the Z.10 and a doz. of the Z.11 plugs that you sent to us. They were run in a standard production engine. After 3 or 4 minutes full load there were very bad pre-ignitions, so bad that they fired the charge during the induction stroke, causing violent popping. When we took them out we found several porcelains cracked and all of them shewed signs of being over-heated. Yours faithfully, | ||