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).
Extract note regarding the fitting of stronger valve springs.
| Identifier | ExFiles\Box 80\3\ scan0206 | |
| Date | 22th October 1915 | |
| Extract from 28230 of the 22-10-15. re AQ & P2 Stronger Valve Springs E519s have been fitted to AQ & P.B sgd. H.E. Matthews X290 | ||