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).
Standardisation and testing of Bentley engine compression ratios.
| Identifier | ExFiles\Box 86\1\ scan0024 | |
| Date | 26th July 1933 | |
| xna To By.{R.W. Bailey - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} c. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} c. Mx.{John H Maddocks - Chief Proving Officer} Sft.{Mr Swift} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}7/KT. 26.7.33. BENTLEY COMPRESSION RATIOS The Bentley at present running in France has a compression volume of 97 cc. This we think should be established as standard. There is some question as to what compression ratio this gives owing to the variation in gasket thickness. However, we are making tests with thinner gaskets which will not vary much between the new and the used thickness. We consider that on the Bentley engine with its high compression ratio, we ought to ensure that the compression volume has the minimum variation from cylinder to cylinder. We have actually checked three heads, taken from production, to drawing EB.615, with the attached results. We think that these should be quite satisfactory in that the maximum variation between any two cylinders is not more than 2 cc. From studying the limits on the drawings, however, we believe it will be possible to get a greater variation than this, and it is only by working at one end of the limits that the consistency at present shewn has been obtained. We should be glad if you will look into this and also arrange for a production test to be made on all compression volumes of all cylinder heads. This is now done on all American cars and Sft.{Mr Swift} has a sketch shewing a rig utilised by the Packard people which enables the check to be carried out very expeditiously. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||