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).
Mysterious exhaust valve failures in car units, suspecting leaded fuel as the cause.
| Identifier | ExFiles\Box 88\4\ scan0029 | |
| Date | 8th September 1933 | |
| X 254.. To Wor.{Arthur Wormald - General Works Manager} From Hw/Hm.{Capt. W. Hallam - Head Repairs} Cc. C. E.{Mr Elliott - Chief Engineer} Cc. Hy.{Tom Haldenby - Plant Engineer} Rg.{Mr Rowledge} Cc. Ph. Dm.{D. Munro} Cc. EV.{Ivan Evernden - coachwork} Hw/Rsl/KT.8.9.33. VALVE FAILURES ON CAR UNITS. We have recently had several mysterious exhaust valve failures on our test bed engines. We have never had such failure on the road. They have occurred on both the Bentley and Phantom. The Bentley failure occurred after approx. 7½ hrs. at full throttle 4200 r.p.m. when we were reproducing the GML piston failure in France. Up to the present our investigations lead us to believe that the failure is due to our using fuel containing lead. Under continual full power conditions this appears to cause a deposit on the valve seat which insulates the valve from the head, thereby preventing heat flow through the seat. In spite of the low concentration of lead in the ordinary Ethyl fluid, it has apparently been sufficient to cause the trouble. We have been running all cars in the Expl. Dept. on Ethyl for about three months, and on examining a head which has done its majority of running on the road, we found signs of the same valve trouble but in a very mild degree. The trouble is not altogether new as it has been experienced in America and a cure applied in the form of stellited valve seats, also we have had it on our own aircraft engines. We are carrying out investigations to overcome the troubles experienced. Hw/Dm.{D. Munro} | ||