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).
Modifications to a 20 HP engine, specifically increasing the bore size for improved power and performance.
| Identifier | ExFiles\Box 103\4\ scan0044 | |
| Date | 1st April 1929 | |
| To R: from Hs.{Lord Ernest Hives - Chair} c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} c. to BY.{R.W. Bailey - Chief Engineer} X5050 Hs{Lord Ernest Hives - Chair}5/LG22. 4.29. 20 HP. ENGINE. X5770 We have a 20 HP. engine unit running in which the bore has been increased to 3.2". This was E's original suggestion, but since then it has been altered to 3.25". We measured up an existing 20 HP. block [word crossed out] and came to the conclusion that experimentally the bores could be bored out and larger pistons fitted to obtain information. Wor.{Arthur Wormald - General Works Manager} agreed that this should be done. The engine has been run on the test bench and the increase in power over the standard engine is 15%, at high speeds the increase falls to 9 or 10%. We expect to have the car running tomorrow with this engine fitted, and we hope to shew a marked improvement in performance. Hs.{Lord Ernest Hives - Chair} | ||