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).
Investigation into engine misfires caused by K.L.G. sparking plugs on cars 36-EX and 5-B-IV.
| Identifier | ExFiles\Box 162\5\ img001 | |
| Date | 23th April 1937 | |
| To Rm.{William Robotham - Chief Engineer} c. to Wst. c. to Rm{William Robotham - Chief Engineer}/FD.{Frank Dodd - Bodies} 6001 Rm{William Robotham - Chief Engineer}/WB.{Mr Brazier/Mr Bell}6/JH.23.4.37. K.L.G. Sparking Plugs. We have been investigating the cause of misfires on 36-EX and 5-B-IV and on both cars have traced it to the sparking plugs having too large a gap. These had increased from .020 to .030" during the mileage. With the points closed to the normal setting no further trouble was experienced, both cars giving good slow running and pick up. Inspection of the plugs shows a considerable burning of the G.{Mr Griffiths - Chief Accountant / Mr Gnapp} type earth, and as the mileage is small, we consider this should be taken up with K.L.G. immediately. 36-EX is fitted with K.L.G. E.26 (present standard) and 5-B-IV with K.L.G.E.28 which is a cooler plug then E.27, (present standard). The mileage run by the two cars before misfiring - 36-EX 3920 miles, 5-B-IV 1760 miles. We consider that with our present electrical system we cannot allow the spark gap of a plug which has done mileage, to increase beyond .025" without running into misfires. Rm{William Robotham - Chief Engineer}/W.Brazier. | ||