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).
Summary of bench test results on 'Japan' engines to improve power output by testing various components.
| Identifier | ExFiles\Box 5a\5\ 05-page142 | |
| Date | 30th June 1931 | |
| FOR FILES. 8571 Ha/Rm.{William Robotham - Chief Engineer}8/WJ.30.6.31. A number of bench tests were carried out on 'Japan' engines with a view to improving the power output. Curve V.1160 shows the back pressure due to the various exhaust systems. Curve V.1159 indicates the reduction in power loss that can be obtained by using two Claudel carburetters instead of the twin choke Zenith, although actually the manifold depression measured with the two Claudel carburetters was higher than that given with the twin choke Zenith. Curve 1148 shows how sensitive the power output at high speeds is to the exhaust valve duration and lift. With this carburetter etc. one would be inclined to say that the exhaust valve cam was not sufficiently long duration or high lift. With regard to curve V.1162. This shows the effect of even a free exhaust system on the power output of the 'Japan' engine. Once again the loss is far higher than we should expect. Curve V.1161 shows the effect of varying the timing on the 112° camshaft. This is called long duration camshaft, but actually it will be observed that it is no longer duration than the 112° camshaft. Ha/Rm.{William Robotham - Chief Engineer} | ||