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).
Engine performance data (HP vs RPM), valve timing settings, and valve contour specifications.
| Identifier | ExFiles\Box 124\3\ scan0037 | |
| Date | 7th May 1919 | |
| R.R. 238A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. -2- EH2/LG.7/5/19. Revs. | H.P. | H.P. with open exhaust. ---|---|--- 500. | 8.3 | 8.7 750. | 12.7 | 13.6 1000 | 17.3 | 18.9 1200 | 20.6 | 21.8 1500 | 24.3 | 26.6 1750 | 26.52 | 28.7 2000. | 23.3 | 27.8 The Valve Timing with 10 thous. clearance in the Tappets is as follows:- I.O 18º P.T.D.C. I.C. 30º P.B.D.C. E.O. 48º B.B.D.C. E.C. 4º P.T.D.C The Valve lift taken with no clearacne at all in the tappets is .268" for the inlet .271" for the exhaust. The Valve Contours are as follows:- Degrees on Camshaft. | Inlet. | Degrees on Camshaft | Exhaust. ---|---|---|--- 0º | .000" | 0º | .000" 5º | .005" | 5. | .001 10º | .025 | 10. | .003 15º | .053 | 15. | .021 20º | .091 | 20. | .043 25º | .132 | 25. | .072 30º | .172 | 30. | .118 35º | .211 | 35. | .162 40º | .239 | 40. | .200 45 | .258 | 45 | .229 50 | .268 | 50 | .253 55 | .263 | 55 | .267 60 | .251 | 60 | .271 65 | .230 | 65 | .271 70 | .205 | 70 | .271 75 | .169 | 75 | .271 80 | .124 | 80 | .270 85 | .082 | 85 | .260 90 | .047 | 90 | .244 95 | .020 | 95 | .221 100 | .006 | 100 | .182 105 | .001 | 105 | .144 110. | .000 | 110 | .099 | | 115 | .058 | | 120 | .037 | | 125 | .020 | | 130 | .001 | | 135 | .000 | ||