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).
Valve spring failures and modifications for B.60 and B.80 engines.
| Identifier | ExFiles\Box 124\1\ scan0107 | |
| Date | 16th May 1939 | |
| 1044 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} c. Da{Bernard Day - Chassis Design}/Jnr.{Charles L. Jenner} c. By/CS. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}4/MH.{M. Huckerby}16.5.39. B.60 & B.80 VALVE SPRINGS. We have had to resort to the use of Ph.III double valve springs on the inlet valves of the above units in order to overcome failures experienced on single springs, which when loaded to overcome bounce, are overstressed. Even though the Ph.III springs have been the most satisfactory up to the present, we still experience occasional failures, also they are bad for surge. Double springs on the same lines but with close coiling at the base to overcome surge, and in Swedish wire, have been designed along with the new B.60 cylinder head PD.368. We should like details of these springs adapting to our existing B.60 and B.80 engines, as at present we are fitting them up with Ph.III double springs "mocked up" in an experimental manner. Regarding the exhaust valve springs, these are of the single type EB.3256, which are in Swedish wire, produced by The Tempered Spring Co., and have run throughout the tests on the B.60 and B.80 without a single failure. Irrespective of tooth form modification on the distributor drive gear, we have found that the gears are invariably in better condition when fed by high pressure oil which produces a jet squirt, rather than a trickle with low pressure. This conversion has been carried out on our B.60 and B.80 units and would like drawings etc. to instruct this job in an official manner. Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||