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).
Valve seat erosion in Eagle 9 and Condor engines, investigating the causes and examining a specific cylinder.
| Identifier | ExFiles\Box 66a\2\ scan0020 | |
| Date | 12th April 1926 | |
| To R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} c. to BJ. RG.{Mr Rowledge} c. to BY.{R.W. Bailey - Chief Engineer} Hs.{Lord Ernest Hives - Chair} x8060 E1/M12.4.26. RE. EAGLE 9. & CONDOR VALVE SEAT EROSION. X.3615 X.3930 X.8060 Re. BY7/H9.4.26., during our visit to Derby we saw further examples of valve seat erosion in which the valves had cut what were apparently perfectly circular recesses in the cyl.head. It will be remembered that the first sample of this erosion sent to us had an oval recess. We conclude that where there is considerable clearance in the valve guide the erosion becomes oval, but that valve guide wear is not necessarily the cause of the erosion. Since visiting Derby we have made a close examination of the Eagle K.L.M. cyl. sent to us by BY.{R.W. Bailey - Chief Engineer}, and we find there is distinct but not entirely complete evidence of the valve spinning round. The valve spring ends on one end of the exhaust valve springs are circularly polished, as is also the washer in contact with these springs. Inlet valve springs shew no signs of plishing. The exhaust valve itself has worn hollow on its seating face to the theoretical form of the footstep bearing, and is scratched and lined with circular scratches running all round the face. The exhaust valve top gives one the impression that at some time the valve might have been spinning round but that finally it remained still. A peculiarity of this example also is that oil has been pouring over the exhaust side of the cylinder, covering the valve springs and washers. Carbonised oil and dirt is caked on the valve stem boss and exhaust bend flange, and on the exhaust valve itself is a heavy deposit nearly .1" thick in places of oil carbon on the outside of the tulip. This carbon is caked round the tulip where it joins to the stem, and also half way round the skirt on an area near to the valve seat. contd :- | ||