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).
Phantom III valve spring failures and investigation.
| Identifier | ExFiles\Box 96\2\ scan0121 | |
| Date | 29th July 1936 | |
| X354 FILE. Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}15/JH.29.7.36. Phantom III Valve Springs. Of the type standardised; E.{Mr Elliott - Chief Engineer} 87498 outer and E.86364 inner springs, there have been 2 failures on the test bed, 1 outer and 1 inner. 35-EX. This unit has the correct outer springs as fitted in the assembly of the unit 12.9.35. The inner springs are not correct and are to Hs.{Lord Ernest Hives - Chair}1828 which has 21 lb. seat load against the std. load of 14 lbs. (E.86364)spring. 34-EX. This car was brought up to date by the Test Dept. and are assured that the springs are to the correct specification. The springs as marked white are of the type approved by By.{R.W. Bailey - Chief Engineer} and supposed to be similar to the original manufacture. From the reports on 10,000 miles test on 32-EX there has not been a single valve spring failure and in conjunction with the odd failure on the test bed it is more or less conclusive that the wire is either faulty or the tempering of the wire is not correctly carried out. We think that the breaking of the keeper rings occurs when the valve springs are being interchanged and the top cap pushed down too far or not squarely when the wedges are removed. Although we know the feed to the tappet screw ball ends is scanty we have not experienced any excessive wear. 32-EX unit has a good film of oil in all the ball ends without any signs of wear. It is however one of our next jobs to improve the lubrication at this point. It is more difficult than would appear to carry out this job and yet keep down the supply to the valve tips. Hs{Lord Ernest Hives - Chair}/L.H.Swindall. | ||