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).
Comparison of different camshafts on the 'Japan' engine and related test results.
| Identifier | ExFiles\Box 102\5\ scan0023 | |
| Date | 19th November 1929 | |
| X 5090. To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/ACL. c. HS.{Lord Ernest Hives - Chair} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Da.{Bernard Day - Chassis Design} Ry. Hs{Lord Ernest Hives - Chair}/ACL2/A19.11.29. CAMSHAFT COMPARISONS ON "JAPAN" ENGINE. x5771 x5090 We have now compared the 116° camshaft with the std. 110° on the "Japan" engine. The results - shown on V.749 - are similar to those obtained on the "China" engine. The 116° camshaft shews a disadvantage up to 2750 R.P.M. and above this speed the gain of only 2% does not seem sufficient to discount the loss at the lower speeds. On the large valve "China" engine the gain at the high speeds amounts to 7% as shewn on print V.739 supplied with a previous report. This test confirms the results obtained during the power increasing experiments on the small bore 20 HP. when we found that long duration cams gave the best results at high speeds when used with large valves. At the same time that we were carrying out tests on the small bore 20 HP. with the long duration cams we made a test comparing the power output with .006" tappet clearance and .015" tappet clearance, with the idea of getting the effect of a quicker lift cam as suggested in R3/M16.11.29. The only difference we could detect was at the most 2 lbs/sq.in (or 1.5%) in the B.M.E.P. in favour of the .006" tappet clearance between | ||