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).
Dimensioned drawing showing a cross-section of a piston and connecting rod.
| Identifier | ExFiles\Box 148\3\ scan0053 | |
| Date | 20th October 1928 guessed | |
| 2.75" approx varies with compression ratio. 4.250 | ||