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).
Test results for three types of K.L.G. sparking plugs for Bentley engines to address issues with leaded fuel.
| Identifier | ExFiles\Box 142\3\ scan0153 | |
| Date | 5th March 1937 | |
| 1204 To Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} from Rm{William Robotham - Chief Engineer}/W.Brazier. Rm{William Robotham - Chief Engineer}/WB.{Mr Brazier/Mr Bell}15/AP.5.3.37. c. to Wst. c. to FD.{Frank Dodd - Bodies} --------- BENTLEY SPARKING PLUGS. The following tests have been completed to determine a type of sparking plug suitable for the Bentley engine and which will overcome the trouble experienced when cars have been run on lead fuel, under traffic conditions, for lengthy periods. We have tried three types of K.L.G. plugs, which are fitted with a Corundite insulation in place of the previous mica, and which it is claimed will resist attack from lead. It will be seen from the tests that whereas all the plugs tried are almost identical in performance, the K.L.G.E.27. appears to be the one we require. It should be noted however that these tests have all been done with new plugs, and our experience on their life and their resistance to lead fuel attack is limited. K.L.G. E.28. - Corundite insulation G.{Mr Griffiths - Chief Accountant / Mr Gnapp} type external earth. Plug gap .020" Slow running 7 to 8 M.P.H. Idling 350 - 400 R.P.M. 450 R.P.M. fully advanced. Braked down to 7 M.P.H. full throttle. No misfires with plug gaps .020 and .030. TOP SPEED Topped 90 M.P.H. 15 mins. idling, no oil on plugs but running rather cool. --------- K.L.G. E.28. has the same heat factor as the K.L.G. FLB.50.X. but like the E.27. has the G.{Mr Griffiths - Chief Accountant / Mr Gnapp} type external earth which facilitates the setting of the plug gap. --------- K.L.G. E.27. Corundite insulation G.{Mr Griffiths - Chief Accountant / Mr Gnapp} type external earth. Higher heat factor than K.L.G. E.28. Plug gap .020 Slow running 7 to 8 M.P.H. Idling 350 400 R.P.M. 450 R.P.M. fully advanced. Braked down to 7 M.P.H. full throttle no misfires. With .030 gap misfires on pick up were experienced on the standard coil. An EXP.1500 coil cured this. Top speed 90 M.P.H. 15 mins idling no oil on plugs, appeared to be running about right heat. | ||