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).
The failure of valve spring caps during engine and test rig trials.
| Identifier | ExFiles\Box 36\1\ scan 124 | |
| Date | 24th August 1917 | |
| R.R. 2M A.{Mr Adams}(TTo H) S.D. 442. 9-5-17. G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 1966 To R.{Sir Henry Royce} from EH. c. to BJ. c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} X.2925 EH1/LG24.8.17. X.3062 - VALVE SPRING CAPS. We have been running a test rig fitted with six cylinders and a set of the latest solid valves and hardened caps with stronger valve springs. X.3132E. We have had two of the valve spring caps break in 1 1/2 hours running. The speed we are running the camshaft is 1140 revs. equal to 2280 engine revs. X.2925 E/A The caps which are broken are the latest type and when measured up, come within the limits on the drawing. We have also had two valve spring caps break on an engine during normal tests. These were the strengthened type which were made immediately the first caps started to break. The washers are evidently not strong enough when used with the X.2993 stronger valve springs and latest valve gear. We consider they ought to stand 2250 revs: without breaking. If an inlet valve washer breaks, there is a risk of the engine catching fire or at any rate, the induction pipe will get so hot as to melt the solder on the water jacket. EH, | ||