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).
Investigation into methods for reducing engine knock by modifying cylinder skirts with steel sleeves or thicker sections.
| Identifier | ExFiles\Box 48\1\ Scan179 | |
| Date | 1st October 1925 guessed | |
| contd :- -5- us that the cylinder block was a contributing factor and it was therefore thought advisable to direct our attention to this as a possible means of eliminating or mitigating the trouble. A steel sleeve was shrunk over one of the cylinder skirts which extended the whole length (see sketch.) DIAGM. I CYLINDER .175 STEEL SLEEVE SHRUNK OVER CYL SKIRT .1300 This arrangement proved to be very satisfactory and the knock which was previously very evident was practically eliminated except for a very slight trace which could only be heard when using a 'sounding rod' on the skirt. If this arrangement were employed it would be necessary to enlarge the bore in the crankcase to allow for elongation of the crankcase with temperature. It was desired, if possible, to try a similar method without having to resort to any alteration of the existing crankcase therefore some cyl. blocks were prepared with thicker section skirts which extended only 2" from the bottom. This required no alteration to the crankcase. The reason for shortening the length of the stiffened section was to discover the amount of stiffening necessary to obtain the desired quiet operation. Results proved encouraging. When using a sounding rod at the cyl. base 'knocks contd :- | ||