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 stretching on a Phantom model, comparing different steel compositions and proposing a strengthened valve design.
| Identifier | ExFiles\Box 17\6\ Scan032 | |
| Date | 25th April 1928 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. BY.{R.W. Bailey - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} HL. X7060 R3/M25.4.28. PHANTOM - VALVES STRETCHING. X.7060 X.8060 (crossed out) X.1474 There appears to be a difference between low and high silicon valves. HL. says the lower silicon 3.28 is better than the steel 3.86 silicon. This would be a good opportunity of proving whether any particular steel retains its stiffness when hot. E.{Mr Elliott - Chief Engineer} suggests that the silencer may have some influence on the heat of the exhaust valves. I suggest that the French petrol is more liable to cause detonations, and hence heat. We suggest that you now have - (1) The old high silicon steel which is probably the one complained of, (2) the lower silicon silchrome steel, (3) Firths Austenite steel, and (4) the valve & head of the increased section, and if the car is to remain any time in France it will be good to send out at least 3 exhaust valves of each type if you cannot reproduce the fault in England. E.{Mr Elliott - Chief Engineer} and I have examined the design of Phantom valve, and find that it has not received recent improvements. We therefore send a strengthened design in accordance with F.{Mr Friese} engine practice. It is here suggested that present valves should be used for inlet, and new exhaust valves be made at once of this strengthened type in the best steel we know, (2 different steels if you like). To avoid confusion we have slightly increased the size of the stem so that new valve guides will be needed - (HL. suggests alum. alloy experimentally). contd :- | ||