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).
Series of engine tuning adjustments and performance test results.
| Identifier | ExFiles\Box 124\2\ scan0287 | |
| Date | 17th December 1940 | |
| - 10 - Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}/RH.{R. Hollingworth}17. 12. 40. 4. Fitted up cold air intake. 5. Inlet and exhaust valves run with .050" tappet clearance. 6. Ignition timing tried at 10° PTDC and 5° BTDC. 7. Sparking plug gaps tried at .025", .030", .040" and .050". 8. New set of Champion N8 long reach sparking plugs. 9. New set of KLG FLB 30 X short reach sparking plugs. 10. Engine run on 5 cyls. cutting out one cylinder in turn, and also running engine on one cyl. only in turn. There is no distinction between any of the cyls. The only thing we have done to obtain even a slight improvement is to strengthen the induction mixture. We have tried a Cast Iron engine fitted with a Duplex Stromberg carb, but this set up is no better than the Twin S.U. carbs. Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager} | ||