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).
Weights of valve mechanism parts and load/stress data for inner and outer springs.
| Identifier | ExFiles\Box 158\5\ scan0062 | |
| Date | 15th March 1940 | |
| To Rm{William Robotham - Chief Engineer}/Caisley. With reference to your telephone message for particulars enabling further inlet valve springs to be made, I enclose herewith blue print of PL.111 which shows the room available for the wire. If is helpful to you, if I quote the weight of the various parts of the valve mechanism. Inlet Valve - .1986 lbs. Rocker. - .25 lbs. Adjusting screw. - .0223 lbs. Lock nut. - .0089 lbs. Solid steel push rod - .23 lbs. Tappet. - .2321 lbs. Valve springs. - .239 lbs. Washer & wedges. - .0656 lbs. The double springs that have been used more or less successfully are as shown in the tables below :- Inner spring E.86364 Load. | Stress. Closed. | 14½ | 20,000 Open | 40 | 56,000 RATE 64 lbs. Outer spring E.88325 Load. | Stress. Closed | 43.8 | 27,000 Open | 113.8 | 63,000 RATE 174 lbs. Cont'd.{John DeLooze - Company Secretary} | ||