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).
Modifications to the valve timing for the Goshawk engine.
Identifier | ExFiles\Box 33\4\ Scan072 | |
Date | 7th June 1923 | |
To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to CJ. CY. EP.{G. Eric Platford - Chief Quality Engineer} X1770 R4/M6.7.23. GOSHAWK VALVE TIMING. X.1770 X.4226 I understand from the experiments on Gos.1. that it is advisable to somewhat modify the valve timing on Goshawk 11., and in our discussion we concluded that it will be safe to immediately change the angle between the exhaust and inlet valve cams from 118º to 110º., and that you have proved there is no disadvantage in a considerable amount of lap between the exhaust and inlet cams. In our discussion I suggested that the experiments had shewn that an increase in the length of the exhaust cam was desirable, and will be instructed, but that the inlet cam was at present about the best we could make it. We also note that you wish to consider only valve timing with a clearance of .010" because of the misleading and difficulty arising when the valves are adjusted to a fine clearance because the length of the slow moving silent foot to the cam gives an indefinite and variable timing to the valve open or closed, with unavoidable small differences in the small clearances to usually adjust to. This silent foot is the probable reason for our instructing having resulted in a slightly imperfect proportion and timing. R.{Sir Henry Royce} | ||