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).
Experiments and testing of new valve springs made from 'Swedish wire' versus standard springs.
| Identifier | ExFiles\Box 158\4\ scan0131 | |
| Date | 5th March 1937 | |
| 1360. Sg.{Arthur F. Sidgreaves - MD} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. to Hs.{Lord Ernest Hives - Chair} c. to By.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}8/R.5.3.37. VALVE SPRINGS. The tenor of the memo By2/G.4.3.37. appears to be that the "Swedish wire" is not up to the standard of our normal Chrome-Vanadium wire. To us this is not the issue, as our object is an endeavour to produce springs which are cheaper and as reliable as our standard springs. In view of the promising results we have had with closely coiled valve springs, as made for us by the Tempered Spring Co. in "Swedish Wire" to our drawing Rm.{William Robotham - Chief Engineer}260, and the fact that if made by us would save 66% in cost, it appears to be rather premature to discuss the merits of the wire at such an early stage. It must be realised that the trial of new valve springs both in material and design is an experiment which must be extended over long periods of running before any real opinion can be given. The history of our experiments is as follows:- (1) Received from America P.III valve springs which were closely coiled at the base. These proved exceptionally free from surge. (2) The close coiling we interpreted to the Bentley valve spring EB.175 drawing and place an order for such springs in "Swedish wire" with the Tempered Spring Co. These Rm.{William Robotham - Chief Engineer} 260 springs were free from surge throughout the speed range and have been run on 3 test bed units over a total of 135 hours, 25% of which time at speeds from 4000-4500 RPM. without a single failure. Other than the test bed units both 3.B.IV. and 6. B.II are running 10,000 miles' test equipped with 4 of these springs on each car. No such springs have ever been run on the valve rig. | ||