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).
Specifications for engine components including cams, valves, and valve springs.
| Identifier | ExFiles\Box 126\5\ scan0144 | |
| Date | 8th March 1938 guessed | |
| - 4 - Lash in chain is taken up by two flat strips of spring steel which are riveted into the sheet metal timing cover. See sketch SS.{S. Smith}20.19. CAMS. (SS.{S. Smith}17) Width - 9/16" Cam Lift Approx. .359 A cam form chart is available - See Ex.S.980. VALVES. (SS.{S. Smith}20/21) A spring damper is fitted. Stem diameter: Inlet .309 Exhaust .312 Stem clearance in guides .003 - Tappet clearance .012 - Inlet and Exhaust. Head Diameter: 1.659 Inlet 1.472 Exhaust. Valve Ports 1.7/16" dia. inlet. 1.5/16" dia. exhaust. Valve Face Angle 30° Inlet and Exhaust. Length of Valves 5.718 Inlet 5.727 Exhaust. See sketch SS.{S. Smith}20. VALVE SPRINGS. (SS.{S. Smith}88/89) MAIN SPRING. Length in position 1.850 Outside diameter 1.375 Free length 2.575 Diameter of Wire .156 9½ Coils. 7½ Working coils. INNER SPRING. Length in position 1.850 Outside diameter .904 Free Length 2.230 Diameter of Wire .116 11¾ Coils 9 Working Coils. | ||