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).
Use of aluminium bronze for valve seats and associated design precautions.
| Identifier | ExFiles\Box 66a\2\ scan0037 | |
| Date | 25th September 1926 | |
| To RG.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} FROM R.{Sir Henry Royce} X8060 R4/M25.9.26. RE. VALVE SEATS+ X.8060 X.3822 We hear that the Americans are entirely in favour of alum. bronze for valve seats, even though the appearances after preliminary runs are a little bit disappointing. They also say that this alloy can be materially improved by heat treatment after casting. You will see that we have expressed a view that the valve seats must be put in with a serrated driver, so as to better judge their tightness, that as soon as possible a little more thread shall be provided, and also an undercut or other locking arrangement will be provided. These precautions, together with the triple valve springs which give much less motion to the valve, and with the outer valve spring coiled in a direction that the motion due to this spring shall be in the right direction to screw in the valve seat, should be taken at the earliest possible moment. In addition Hs.{Lord Ernest Hives - Chair} remarks that any screws in alum. should be fitted with inserts as the stripping of threads in alum. seems a regular fault. Personally I have not seen the alum. correctly tapped for the steel screws. I think there should be taps of definitely smaller size, that will enable the screws and studs to be put in with a tight thread. There is much to be learned from the American practice. R.{Sir Henry Royce} | ||