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 the Bensport Cylinder Head to increase the compression ratio.
| Identifier | ExFiles\Box 86\1\ scan0017 | |
| Date | 13th May 1933 | |
| x219- To BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} E.1/HP.13.5.33. Bensport Cylinder Head. ----------------------- We understand from the Experimental Department that from their observations of other cars we are likely to be up against in the Bentley class, our compression ratio is definitely on the low side, and we may be at a disadvantage thereby. It is desired, therefore, to put ourselves in a position to raise the compression ratio with the least amount of trouble when desired by machining .05" off the bottom of the cylinder heads. As the floor of the head is at present of minimum thickness it will be necessary to alter the corebox so that the present floor will be increased in thickness .050". We have looked into this from the design question and we do not see any difficulty. The resultant increase of compression ratio by calculation with .050" removed from the bottom of the head and the internal machining of the combustion space so modified as to retain the present shape and thickness of the lips will be from 6.35 to 6.6. E.{Mr Elliott - Chief Engineer} | ||