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).
Napier valve springs with detailed measurements for exhaust and inlet springs.
| Identifier | ExFiles\Box 80\3\ scan0235 | |
| Date | 28th February 1913 | |
| T.S.H. 28:2:13 Report on Napier Valve Springs. X74 (crossed out) X438 Cyl. No. | Exhaust Springs | Inlet Springs ---|---|--- | Length of sprg. (valve open) | Length (valve closed) | Length of sprg (valve open) | Length (valve closed) 6 | 2.670" | 3.090" | 2.680" | 3.065" 5 | 2.700" | 3.140" | 2.740" | 3.095" 4 | 2.680" | 3.095" | 2.715" | 3.085" 3 | 2.680" | 3.100" | 2.745" | 3.045" 2 | 2.675" | 3.095" | 2.690" | 3.055" 1 | 2.685" | 3.125" | 2.685" | 3.060" average of above readings | 2.681" | 3.109" | 2.709" | 3.068" Weight on sprg. valve open | 58.375 Weight do valve closed | 38.000 Weight on sprg valve open | 56.875 Weight do. valve closed | 40.375 Weight given is in lbs. Top of spring. 12 turns, right hand. dia. of wire 4 m/m Average length of springs (fully extended 3.900" | ||