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).
Tappet pad wear in the S.S. engine after 50 hours of testing and a proposed solution.
| Identifier | ExFiles\Box 17\6\ Scan056 | |
| Date | 9th November 1928 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/ACL. c. BJ. Wor.{Arthur Wormald - General Works Manager} c. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} By.{R.W. Bailey - Chief Engineer} Y7060 Hs{Lord Ernest Hives - Chair}/ACL1/T9.11.28. S.S. TAPPETS. X7060 The S.S. engine has now completed 50 hours running on various tests and we have stripped it down for examination. We find all the tappet pads have a groove worn in them at the point where they are in contact with the camshaft. These pads are in constant contact with the camshaft, even when the valves are closed, and are held down by the tappet spring. This groove must therefore be caused by the back or base of the cam. We do not experience the same trouble on the aero engines because when the valves are closed there is no load on the rocker to force the pad into contact with the base of the cam. We have examined several F.{Mr Friese} engines and find no signs of this trouble. With increased wear we should imagine the tappet operation would become noisy. If it were possible to arrange for the necessary valve tappet clearance to exist between the tappet pad and cam base instead of between the rocker pad and valve tip, we should imagine much quieter operation would result, as this part would be enclosed and well cushioned with oil. This of course would add to the work of the valve spring. We are sending for your inspection one tappet complete. A report on other parts of the S.S. engine will follow later. Hs{Lord Ernest Hives - Chair}/A.C.Lovesey. | ||