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).
Specification sheet for two experimental 20 HP engines, one with an aluminum turbulent head and the other a modified cast iron standard head.
| Identifier | ExFiles\Box 5\4\ 04-page216 | |
| Date | 2nd May 1929 guessed | |
| contd :- -2- as to be ready with information should it be considered advisable to enlarge the std. model. SPECIFICATION OF ENGINES IN THE TWO EXPS: 20 HP%. Alum. turbulent head engine. (1) This head has a compression ratio of 5.25. (2) The bore is increased by .200". (3) The carburetter chokes and air valve ports are increased by 14%. Mod: cast iron std. engine. (1) This has a compression ratio of 4.7. (2) Bore increased by .200. (3) An India lv. inlet valve is used. The inlet port remains as standard but the seat is bored out larger to take the India lv inlet valve. The valve stem was shortened by .050". The exhaust valve was standard. (4) The carburetter was increased by 14% as above. -------------- Hs{Lord Ernest Hives - Chair}/A.{Mr Adams} C. Lovesey. | ||