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 SS taper valve spring, discussing its current performance and proposed improvements.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan030 | |
| Date | 14th March 1929 | |
| ORIGINAL A.{Mr Adams} FROM E.{Mr Elliott - Chief Engineer} SECRET. E1/M14.3.29. Copy to GS. SS.{S. Smith} TAPER VALVE SPRING. X7060 " HS.{Lord Ernest Hives - Chair} X290 " BY.{R.W. Bailey - Chief Engineer} The present SS.{S. Smith} valve spring seems to be a very good one and we do not propose to disturb it. We do think however that later on when there is more time available some comparative tests should be made with other springs on the valve test rig. With this end in view taper spring LeC. 2681. has been calculated for the SS.{S. Smith} with a view to raising the figures for Natural Frequency and Figure of Merit. The improved figures for these quantities are shewn on the drawing. LeC. 2681. requires .2" more end room and this is obtained by making a deeper recess in the cylinder head for the lower end of the spring. The spring loads are based on maintaining the pressure at one third cam lift constant. Owing to the reduction of the tappet spring pres- sure on SS.{S. Smith} to save wear in the valve closed position, the SS.{S. Smith} is now about the same as Phantom for total pressure at one third lift but nevertheless should run up to a higher speed owing to lighter valve gear and more favourable lift curves. Now that we have seen what can be achieved by adding to the spring length we can go back and try the effect of merely introducing some taper into the existing spring. Blueprint of LeC. 2681. is attached, and the orig- inal sent to BY.{R.W. Bailey - Chief Engineer} E.{Mr Elliott - Chief Engineer} | ||