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).
Technical specification document detailing engine components including induction, exhaust, valve gear, and crankshaft.
| Identifier | ExFiles\Box 6\6\ 06-page003 | |
| Date | 7th May 1934 guessed | |
| - 2 - prefer not to siamese 4 and 5 for convenience in induction heating but it seems impossible to avoid this without lengthening engine. Induction System. To be made up in two ways, both with thermostatic exhaust heating, one with single carburetter as Terraplane 8 and the other with one duplex carburetter with 2/4/2 induction pipe similar to La{L. A. Archer} Salle, Daimler etc. Exhaust System. Exhaust manifold very rigid with short branches only to avoid fracture. Exhaust downtake at front end of engine unless in case of the La{L. A. Archer} Salle induction it is demanded in centre. Valve Gear. (Handwritten: Easy Cams) Double valve springs because although they do not prevent ultimate failure with the unfortunate type of driver, enable continued operation at a lower speed and in the case of an inlet valve spring breakage help to guard against firing the carburetter. Automatic lash adjusters on rocker gear either G.M. or Halford type. Camshaft and tappets working in oil bath and cams with reduced positive acceleration with concentric followers of large radius allowing use of large diameter grinding wheels in production, with standard machine and reduced production costs. Push rods, rockers and operating gear generally of increased rigidity to reduce valve bounce. Crankshaft. (Handwritten: Double stud flywheel bearing cap, Crank-pins small) Five bearing counterweighted shaft of conventional 2/4/2 pattern. Balance masses formed solid with shaft and giving 92 to balance of rotating masses relative to bearing loads. Crank journals 2.5" dia. x 1.625/1.375/1.625/1.375/1.750 long reading from front end of shaft. Crankpins 2.125 dia. We are at present looking into the reasons behind the American practice of large journal diameters as we cannot see that they gain a lot compared with making the bearings all to the largest size and the production costs should be decidedly more unless the stepping happens to be actually a convenience in manufacture as regards boring etc. We should like Sft{Mr Swift}'s comments | ||