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).
Cause of burning exhaust valves and proposing modifications to the valve seat angle and shape.
| Identifier | ExFiles\Box 48\4\ Scan098 | |
| Date | 6th July 1923 | |
| To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to Wor.{Arthur Wormald - General Works Manager} OY. c. to BY.{R.W. Bailey - Chief Engineer} EP.{G. Eric Platford - Chief Quality Engineer} RG.{Mr Rowledge} 74226 R3/M6.7.23. RE. VALVES. X.3616 X.2764 X.4226 We were pleased to hear that you were able to reproduce the burning of exhaust valves as occasionally experienced on cars and aero engines. That you have proved by testing that the trouble is due to incorrect seating of the tappets or something getting under the face and separating the valve from its seating, or pre-ignitions - i.e. some unusual condition. That you have also come to the conclusion that the 45° seat is more reliable than the flatter seats at present our standard practice (30° 40/50, Eagle, etc, and 15° Goshawk and Condor). We are sending you a drawing of the valve modification in shape which should avoid some of the heating experienced in the tulip shaped valve. It is evident that we should at once return to the 45° angle seat, and as soon as we have determined a better shape valve than the present one we ought to adopt it. We propose altering the Goshawk from 15° to 30° because it is a smaller valve and has given good satisfaction with 15°. In the meantime the production of valves should be held up as much as possible. R.{Sir Henry Royce} | ||