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).
Vibration data for a single-cylinder L.C. sleeve valve 4.2' engine under various conditions.
| Identifier | ExFiles\Box 134\1\ scan0106 | |
| Date | 13th October 1938 guessed | |
| SINGLE CYLINDER L.C. SLEEVE VALVE ENGINE 4.2" ENGINE. VARIATION OF VIBRATION WITH DIFFERENT ENGINE CONDITIONS. | | R.P.M. | B.M.E.P. (lbs/sq.inch) | Plug | | Centre of head. | | Head Flange. | | Crankcase. | | |---|---|---|---|---|---|---|---|---|---|---| | | | | Range. | Freq. x R.P.M. | Range. | Freq. x R.P.M. | Range. | Freq. x R.P.M. | Range. | Freq. x R.P.M. | | POWER CURVE | 3000 | 207 | .020" | | .021" | | .010" | 1/2 | .003" | 1/2 | | RUN AT 16" | 3200 | 204 | .022" | | .024" | | .012" | 1/2 | .005" | 1/2 & 1 | | BOOST. | 3400 | 207 | .023" | 1/2 | .025" | 1/2 | .014" | 1/2 | .005" | 1/2 & 1 | | | 3600 | 207 | .024" | | .027" | | .014" | 1/2 | .005" | 1/2 & 1 | | | 3800 | 208 | .026" | | .028" | | .015" | 1/2 | .006" | 1/2 & 1 | | | 4000 | 210 | .036" | | .039" | | .015" | 1/2 | .006" | 1/2 & 1 | | | 4200 | 202.8 | .043" | | .045" | | .015" | 1/2 | .007" | 1/2 & 1 | | | 4400 | 198.5 | .040" | | .042" | | .016" | 1/2 & 1 | .007" | 1/2 & 1 | | | IGNITION. (°advance) | B.M.E.P. | Plug | Insert. | Centre of head. | Head Flange. | Crankcase. | |---|---|---|---|---|---|---|---| | IGNITION | 25 | 142 | .013" | | .014" | | .005" | | .003" | 1 | | ADVANCE RUN | 26 1/2 | 145.5 | .014" | | .015" | | .008" | | .003" | 1 | | | 30 | 150 | .028" | 1/2 | .027" | 1/2 | .015" | 1/2 | .005" | 1 | | 4000 RPM. | 35 | 148 | .033" | | .033" | | .018" | | .007" | 1 | | 5.6" Boost. | 40 | 146.6 | .040" | | .040" | | .022" | | .010" | 1/2 & 1 | | | 45 | 141.4 | .050" | | .050" | | | | .007" | 1/2 | | | BOOST. ("Hg.) | B.M.E.P. | plug | Insert. | Centre of head. | Head flange. | Crankcase. | |---|---|---|---|---|---|---|---| | BOOST RESPONSE | 6 | 151.5 | .023" | | .025" | | .013" | | .003" | 1 | | CURVE. RUN. | 8 | 162 | .025" | | .027" | | .014" | | .004" | 1 | | | 10 | 172.5 | .028" | 1/2 | .028" | 1/2 | .015" | 1/2 | .005" | 1 | | 3920 RPM. | 12 | 185.2 | .030" | | .030" | | .017" | | .005" | 1 | | | 14 | 191.2 | .036" | | .036" | | .019" | | .006" | 1 | | | 16 | 206.5 | .041" | | .042" | | | | .007" | 1/2 | | ||