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 and changes for an alternative camshaft for the Bentley 111.
| Identifier | ExFiles\Box 98\5\ scan0022 | |
| Date | 17th May 1938 | |
| BY/WS. c. Rm.{William Robotham - Chief Engineer} c. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. BY/B. 407 Hives DA.{Bernard Day - Chassis Design}5/G.17.5.38. BENTLEY 111. ALTERNATIVE CAMSHAFT. Please receive herewith E.CD.673 Valve Lift Curves - Faster Opening Toe, Longer Duration Exhaust - Bentley 111. This drawing is in accordance with the request in Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}2/AP.12.4.38. and the diagrams are set out from the formulae supplied by BY/B. The displacement curves differ from the previous valve lift curves to LeC.5426 as follows :- (1). Opening toe velocity on both Inlet and Exhaust is increased from .000825 inches/degree to .001192 inches/degree. (2). Duration over high accelerations on exhaust is increased from 242° to 247° on crankshaft, by adding a 2½° dwell on camshaft at maximum lift. (3). The angle between exhaust and inlet cams is altered from 112° to 112½°. (4). Valve timing at .030" clearance altered as follows :- Inlet opens T.D.C. instead of ½° P.T.D.C. Inlet closes 45½° P.B.D.C. - unaltered. Exhaust opens 5½° P.T.D.C. instead of 1½° P.T.D.C. Exhaust closes 45° B.B.D.C. instead of 43½° B.B.D.C. The closing side of lift curves for both inlet and exhaust are same as LeC.5426 after allowing the 2½° dwell for the exhaust. The cam forms for these lift curves are in hand and will be issued shortly. DA.{Bernard Day - Chassis Design} | ||