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 and suitability of Lodge Sintox 640 and 641 sparking plugs for 25/30 and Bentley engines.
| Identifier | ExFiles\Box 162\6\ img344 | |
| Date | 11th May 1938 | |
| 60026 To Roy.{Sir Henry Royce} c. to Rd. c. to Ry. c. to B/Wst. c. to Mx.{John H Maddocks - Chief Proving Officer} Rm{William Robotham - Chief Engineer}/RO.{C. C. Rose - Export Manager}2/JH.11.5.38. re Lodge Sintox 640 and 641 type sparking plugs. Referring to your memo. Roy.{Sir Henry Royce}1/B.29.4.38. we find that the above type plugs are inferior to the K.L.G. FLB.30.X. type. The rate of the electrode burning is greater. Also, it has been found that when the gap has opened to .040" misfiring occurrs, whereas when the K.L.G. type is subjected to the same conditions regular firing is obtained. The dimensions of the 640 type is not suitable for our 25/30 and Bentley engine as the barrel is too short, however, in this respect the 641 type is correct. Rm{William Robotham - Chief Engineer}/RO.{C. C. Rose - Export Manager} | ||