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).
Design and specifications for compensated type valve lift curves and cams.
| Identifier | WestWitteringFiles\S\2April1928-June1928\ Scan077 | |
| Date | 9th May 1928 | |
| BY: FROM E.{Mr Elliott - Chief Engineer} C. to BJ. HS.{Lord Ernest Hives - Chair} ORIGINAL E3/M9.5.28. EAC.10. VALVE LIFT CURVES. X7060 X7080 X290 We send you herewith drawings LeC. 2558. & 2559. dealing with the above. These drawings give particulars of the accelerations required at the different parts of cams, and R.{Sir Henry Royce} would like you to have the space time curve worked out accordingly and returned to us for inspection. The curves are of the so-called compensated type in which the work required from the valve springs diminishes with the lift, and is less in the second half of the cam than the first half. The valve lift required is .429, and cam lift .325, the latter being the same as on present Phantoms. We shall therefore use the sports type double valve springs and fittings, and this section will be complete when the EAC. 10. exhaust valve has been stiffened up in accordance with our latest requirements. A slight alteration is required to the radius of the rocker arm as shewn on LeC. 2559. to bring the rubbing contact into the desired position on end of valve stem. When working out the figures for the cam from the valve lift correction should be made for the varying leverage of the rocker arm. This does not appear to have been done on Sch. 969. for the Condor engine. The proposed timing diagram for these new cam forms is shewn on LeC. 2558. E.{Mr Elliott - Chief Engineer} | ||