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 testing of Champion and K.L.G. sparking plugs in a Bentley 6.B.IV.
| Identifier | ExFiles\Box 162\3\ img083 | |
| Date | 9th January 1937 | |
| 6000 HOTEL DE FRANCE, CHATEAUROUX, Indre, France. To. Rm.{William Robotham - Chief Engineer} c. Srv. Parts. c. Mr. GWH.{George W. Hancock - Head Chateauroux} WST BENTLEY 6.B.IV. SPARKING PLUGS. I have received the following memo from Sr. " RE.CHAMPION SPARKING PLUGS L.10. " One of our customers has been trying these sparking plugs and has obtained very good results. " I was wondering whether these could be tried out and I could hear afterwards what results you have obtained. 6.B.IV. ran the first 2786 miles on Champion L.10 plugs when they were removed in good condition and K.L.G. E.27 fitted, as mileage was urgently required on these plugs in precedence to all others. One of these K.L.G's was removed with a cracked insulator after 7823 miles, returned to Derby, and replaced by Champion L.10 as no more K.L.G's were available. This has run 4571 miles during which time it has given no trouble. The gap increased from .020" to .030" during this mileage; this seems to be normal rate of wear for sparking plugs under our conditions. A Champion L.B.9 was fitted in No 4 cylinder after the K.L.G. plug was written off by a broken valve. This started misfiring after 3926 miles due to sparks jumping from the terminal to the inlet pipe. It has been returned for examination. A Champion L.10 was fitted in its place and covered 2167 miles when it was written off by another broken valve. We received a memo Rm{William Robotham - Chief Engineer}/Wst.10/JH.9.1.37, stating that the LB.10 plugs run too cool. We believe these differ only from the L.10 in length of body. The terminal is further from the inlet pipe on our L.10 than the LB.9 plugs. The same memo asked us to try LB.9 but was afterwards over-ruled by the urgency for the K.L.G. tests. We conclude by saying that we have found Champion L.10 plugs satisfactory for our running, but have given them no traffic tests. You can possibly give this information. ------------------ Rm{William Robotham - Chief Engineer}/GWH{George W. Hancock - Head Chateauroux}/LMW. Ivan Waller. | ||