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).
Analysis of valve rotation and carbon build-up, with proposed modifications to prevent the valve from spinning.
| Identifier | ExFiles\Box 66a\2\ scan0021 | |
| Date | 12th April 1926 guessed | |
| contd :- -2- The position of the carbon on the skirt corresponds to the rubbing mark on the top of the stem indicating that within the cyl. the deposit on the skirt came next to the cyl. centre. It somewhat follows that the outside half of the valve was hotter than the inside half and either burned off any carbon that tried to form, or burned off carbon that had formed when possibly the valve was turning round. SEE ORIGINAL FOR SKETCH. The presence of the oil in this example may be purely accidental, and it is difficult to imagine that it might be the cause of the supposed spinning of the valve, but this could be tested in conjunction with out of centre tappets. In any case we think there is sufficient evidence of the valve rotating to warrant the suggestion that we should try holding the valve still. One way of doing this would be to turn up each end of the valve spring and engage the turned up ends with holes drilled in the valve washers. The valve washers in turn have to be engaged with the valve guide and valve stem by suitable teeth and grooves. Alternatively we might consider a valve guide which was splined at the upper end to engage with grooves in the valve stem. It would be necessary to make this splined piece detachable so that the valve could be ground in on its seating. SEE ORIGINAL FOR SKETCHES* E.{Mr Elliott - Chief Engineer} | ||