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).
Tests carried out on a 112° long duration camshaft for the 'China' engine.
| Identifier | ExFiles\Box 5a\5\ 05-page102 | |
| Date | 20th December 1929 | |
| V5771 To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. c. to EG. WOR.{Arthur Wormald - General Works Manager} c. to S. Gs. c. to Ry. Hs{Lord Ernest Hives - Chair}/ACL.2/WJ.20.12.29. 112° LONG DURATION CAMSHAFT (CHINA). Tests have now been carried out on the "China" engine with a long duration camshaft having an angle of 112° between the cams, (E.55640). This camshaft has the same cams as fitted to the previous 116° camshaft (E.55362). The tests were run on engine No. Gos - C.1, fitted with pistons giving a compression ratio of 5.25, a larger induction passage through the cylinder block (see V.716) and a 20 HP. R.R. having chokes etc., giving a 17% increase on standard. An open exhaust power curve of this camshaft will be found on V.761. Three different timings have been tried; one tooth earlier and one tooth (7.5° on flywheel) later than that given on V.761. The former gives an increase of .3 BHP at 500 R.P.M. but a loss of 3.2 BHP at 3500 R.P.M.; while the latter gives a loss of .3 BHP at 500 R.P.M. and a gain of 1.2 BHP at 3500 R.P.M. It will be noticed that when compared with a standard 110° camshaft (E.54115), this shaft shows an increase in power at speeds above 2250 R.P.M. that amounts to 4 BHP at 3250 R.P.M. Below 1500 R.P.M., however, the standard shaft is superior. It is interesting to note that the 112° camshaft gives more power than the 116° shaft throughout the entire speed range. On comparing the timings of these two shafts it is found that the only difference occurs in the position of the inlet cam.(the duration of lift being approx. the same). | ||