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).
Fitting of an aluminium head to a 20 HP engine, its effect on power, carburetter limitations and compression ratios.
| Identifier | ExFiles\Box 5a\5\ 05-page202 | |
| Date | 8th August 1928 | |
| To NA.{Mr Nadin} From Hs{Lord Ernest Hives - Chair}/P Hs{Lord Ernest Hives - Chair}/RaL/L.G18. 8.28. X5771 X5770 With reference to NA{Mr Nadin}2/B8728. The engine fitted to Mr. Royce's car was an absolutely standard 20 HP. unit. In two or three weeks we hope to fit it with an aluminium head. When the aluminium head is fitted the power will not go up very greatly because we have no carburetter which will give Rolls-Royce acceleration, petrol consumption etc., and at the same time a low induction pipe depression at high speeds. With the present standard RR. carburetter we do not anticipate getting a good high speed horse power. It will be some time before we develop another carburetter. The new head with raised compression may put up our power 10%. R's 20 HP. car rode like a standard 20 HP. car - it has only a longer wheelbase, the springs are identical with present standard practice. Standard 20 HP. comp: ratio 4.6/1. Proposed . . . . . 5.5 (approx.) Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||