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).
And comparing engine measurements for various Bentley models.
| Identifier | ExFiles\Box 21\2\ Scan067 | |
| Date | 1st August 1929 | |
| TO: MR.W.E.ROOTES FROM: MR.H.HEATH 1st.August,1929. Referring to a request for measurements of the Bentley the information required is as follows:- The diameter of the pins and journals 6 1/2 Litre - 55 m/m each. = 2.166" The over all length between the front and rear main bearings taken from the outside is 970 m/m.{Mr Moon / Mr Moore} = 38.2" From the inside of the bearing - 866 m/m.{Mr Moon / Mr Moore} = 33.86" These measurements are the same for the standard Bentley as the speed model. In the case of the super-charged 4 1/2 Litre this engine is entirely different although details cannot be obtained. I understand that crank shaft bearings and connecting rods are different on the 4. litre. Dimensions on S.S. are: Pins 2.125 Journals 2.625 Overall length { outside bear'gs 37.45" { inside " 32.425 i.e. Bentley is actually longer. Tom. | ||