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).
Valve gear failure on the B.60 unit and proposing design changes for various engines.
| Identifier | ExFiles\Box 158\4\ scan0273 | |
| Date | 8th December 1938 | |
| 1360 also 104H To Da.{Bernard Day - Chassis Design} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. Da{Bernard Day - Chassis Design}/MOS. c. By/CS. c. HFS. VALVE GEAR. During the endurance on the B.60 unit an inlet valve went into the cylinder and through the pistons. The trend of events we consider were, (a) Valve spring failed. (b) Push rod dropped to one side of the adjusting screw sphere. (c) On cam lift, the push rod edge got under the adjusting screw sphere and by the higher lift forced the valve through the top washer. As carried out on Ph.lll the push rod cup should be raised so that in the event of a spring failure the rod cannot fall out from the adjusting screw sphere. This should also apply to B.80, Wraith and Bentley V.{VIENNA} Regarding the above application to the rods for B.60, this should be carried out on the tubular steel push rods with flash butt welded ends as recommended by Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} Likewise the housing in the bottom tappet should be sufficiently deep to prevent the push rod gutting out. The expansion rate of the dural rods is too high. In view of the above we should hold up on push rods for B.60 and B.80. There is no recess provided in the top of the valve guides to trap the spring ring and should be included as per EB.1783. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||