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).
Engine tests observing valve and cam motion under different carburetor and timing settings, including a diagram of a cam and roller.
| Identifier | ExFiles\Box 42\3\ Scan063 | |
| Date | 13th December 1926 guessed | |
| contd :- -2- observe no difference between this and the previous test. The next step was to again use the two three cyl. pipes and run on one carb. only, which enabled the other carburetter throttle opening to be varied at will while the engine was running. It was expected some difference in valve motion on the three driven cylinders would exist between open and closed throttle due to the amount of air allowed to pass the valve but no difference was observed - the bounce being the same as mentioned above. The exhaust valves were closely watched when running with the throttle shut as they would then be subjected to a high suction from the cyl. but in this case, as in all other during these tests, they seemed to rigidly follow the cam. The timing was altered - in one case the inlet closed at bottom centre and in the other 90º after bottom centre without any observed variation in valve motion. [text struck through] Aside from the matter under investigation, we noticed during these tests that most of the valves and springs were steadily rotating and all in the same direction. Consequently we placed some washers over various studs on the cyl. - such as the tappet cover holding down bolts - so they were just free on contd :- Text from diagram: ROLLER LEAVES CAM BOUNCE PATH OF CR.{Mr Cra???ster / Mr Chichester} OF ROLLER DIRECTION OF ROLLER RELATIVE TO CAM | ||