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 test results for two types of valve springs.
| Identifier | ExFiles\Box 80\3\ scan0077 | |
| Date | 7th November 1911 | |
| M Rhodin X290 REPORT ON VALVE SPRINGS November 7th 1911 (a) Normal length 3 9/32" number of convolutions 10 1/4 end to end of wire, 9 5/8 full section of wire. Compressed to 2" pressure 42 lbs. Compressed to 1 9/16" pressure 57 lbs ( ie 7/16" lift ) Check a block at 1 5/8" As fitted to speed car 1701 To reduce stress in wire, now running. (b) Normal length 3 7/32" number of convolutions 10 1/4 end to end of wire. 8 5/8 full section of wire. Compressed to 2" pressure 42 lbs. Compressed to 1 9/16" pressure 58 lbs ( ie 7/16" lift ) Standard spring. block a block at 1 1/4" | ||