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).
Required capacity for altered Bentley engine head castings to achieve the correct compression ratio.
| Identifier | ExFiles\Box 86\1\ scan0019 | |
| Date | 19th May 1933 | |
| X219. To RHC.{R. H. Coverley - Production Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}11/KT.19.5.33. BENTLEY COMPRESSION RATIO. With reference to the 6.6/1 c.r. head which we have asked for, for the 4th. Bentley, the heads now being produced should have 103 ccs. capacity which gives 6.3 c.r. The capacity of the heads to give 6.6 c.r. should be 97 ccs. Will you please make sure that when they do get the altered castings through as instructed by E.{Mr Elliott - Chief Engineer} there is enough metal on the bottom face to obtain 97 ccs without reducing the metal thickness below the safety line. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||