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).
Design drawing for a piston, showing dimensions and valve timing information.
| Identifier | ExFiles\Box 170\2\ img027 | |
| Date | 2nd April 1917 | |
| 1250J - Piston 9H/part 60-140-150-200-220 DG64 Inl. Valve and part ths 40° Retard Timing 640 M 2/4/17 Exh Valve Piston Opens 50 60 2-019 A 7 | ||