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 report on the performance of a 112° long-duration camshaft, codenamed 'China'.
| Identifier | ExFiles\Box 5a\5\ 05-page113 | |
| Date | 26th April 1930 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/CHP. c. to Sc. E.{Mr Elliott - Chief Engineer} c. to Sv. M.{Mr Moon / Mr Moore} c. to Wor.{Arthur Wormald - General Works Manager} 112° LONG DURATION CAMSHAFT ("CHINA"). This camshaft (E.55641) has been tested previously and a report circulated (dated D),12,29) dealing with its behaviour in a standard 5.25 compression ratio "China" engine. Referring to the curve V.741 (issued with that report), it is noticed that the B.M.E.P. obtained with the 112° camshaft falls below that obtained with a standard camshaft at speeds under 1500 R.P.M. In order to prevent this falling-off of B.M.E.P. at low speeds, the compression ratio of the engine has been increased accordingly. Tests have now been carried out on engine No. 004.C.1., with a compression ratio of 5.75, all other conditions being identical to the original tests. An open exhaust power curve is given on V.840; also a curve of the same engine, with a Std. camshaft (110°) and compression ratio (5.25), is given for comparison. Three different valve timings were tried; one tooth (7.5° on flywheel) earlier and one tooth later than that given on V.840. The former gives an increase of .3 BHP at 300 R.P.M. and a loss of 2.6 HP at 3500 R.P.M., while the latter gives a loss of .5 BHP at 750 R.P.M. and an increase of 1.7 BHP at 3500 R.P.M. It will be noticed that the 112° camshaft | ||