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).
Two different valve gear rocker geometries to minimise scrub and valve noise, referencing a trial on a Phantom engine.
| Identifier | ExFiles\Box 17\6\ Scan029 | |
| Date | 7th March 1926 | |
| Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} c. to BJ. R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} X. 7060 E5/M7.3.26. EAC.10 VALVE GEAR ROCKERS. ------------------------- Our present standard practice as regards the geometry of valve rockers is to arrange the rocker pivot about 1/3rd. of the travel below the top of the valve stem, so that the minimum of scrub is occurred at the time of maximum load. The practice last recommended by the Expl: Dept: was to place the pivot level with the top of the valve stem so that the minimum of scrub occurred at the moment of the valve being seated. This was said to cure valve noise caused by the valve approaching its seat out of line. To prove the value of this recommendation a scheme of vertically guided tappets was drawn for trial on a Phantom - LeC.2411 which the rockers operated on well fitting vertically controlled tappets. We should be glad to know if you have arraived at any conclusions from the experiment so that we can decide what should be done on EAC.10. E.{Mr Elliott - Chief Engineer} | ||