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).
Investigation into the cause of continued loss of clearance in the exhaust valves.
| Identifier | ExFiles\Box 11\3\ 03-page412 | |
| Date | 8th July 1931 | |
| To K.{Mr Kilner} Her. SG.{Arthur F. Sidgreaves - MD} To Hs.{Lord Ernest Hives - Chair} Dy.{F R Danby} F.{Mr Friese} From G.W.H. Hotel de France, Chateauroux, France. 25-SX. RE. LOSS OF CLEARANCE IN EXHAUST VALVES. We have dismantled the cylinder head to find the cause of the continued loss of clearance in the exhaust valves. We find that this is due to the tulip head stretching and the cause is lack of sufficient cooling. No.1 exhaust valve is the worst offender, No.6 is the next, 2 & 5 are not quite so bad, whilst 3 & 4 give hardly any trouble at all. We attribute these results to the amount of metal in proximity to the valves and water space. The distance between No.3 & 4 exhaust valves is almost double to that between 1 & 2, 5 & 6. No.1 exhaust valve cooling water is at the maximum temperature. In our opinion it is the cylinder head which is at fault rather than the design of valve head. We give the following chart of the valve clearances taken each morning before starting up the engine. This ensures as accurate as possible the same conditions. | ||