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).
American and Daimler developments in cylinder bore accuracy and piston design for improved engine performance.
| Identifier | ExFiles\Box 128\1\ scan0167 | |
| Date | 14th March 1934 | |
| X353/1 To Sg.{Arthur F. Sidgreaves - MD} and Wor.{Arthur Wormald - General Works Manager} from E.{Mr Elliott - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} By.{R.W. Bailey - Chief Engineer} Sft.{Mr Swift} E.5/HP.14.3.34. re American and Daimler Developments. While Mr Pomeroy was over here for the graduates dinner he told me that on his last visit to America he found that the Americans were spending thousands of pounds on development work for improving the accuracy of cylinder bores, and the avoidance of distortion therein, and that his own Company had taken up this same development. The results already claimed appear to be remarkable if they can be achieved in production, and are as follows:- (1) The reduction in oil consumption to about one third or a quarter of the present figure. (2) Decarbonization period increased to 40,000 miles. (3) Reduction of gas blow by to one cubic ft. per hour. per eng. measured by gasometer. (4) Considerable reduction in oil sludging, engines run for long periods on oil retaining original clarity. The alterations which are said to produce these results are diamond bored cylinders, modifications to design of cylinder block to overcome distortion, the use of anodically treated silicon aluminium alloy piston, and the use of a special form of piston ring with sealed annulus retaining and isolating some lubrication for preventing ring dryness. This feature on the piston ring consists of an interrupted annulus on the bottom edge of the ring, the ends of which occur before the ring joint is reached, and are thereby sealed. Mr Pomeroy said that the Americans in some cases were actually finishing their cylinder bores with the heads clamped on in position so that the distortion occasioned by the pull of the stud bosses should not upset the final result. He himself was proposing to design an engine without a detachable head at all as he could see no objection to this if the decarbonising period could be increased to 40,000 miles, and he would thereby avoid the head bolt distortion, save | ||