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).
Addition to a report summarising suggested alterations and re-designs for automatic tappets.
| Identifier | ExFiles\Box 17\6\ Scan198 | |
| Date | 27th February 1934 | |
| -6- Addition to Report on Automatic Tappets. We should like to summarise the above report in the following suggested alterations and re-design of these tappets :- (1) Either (a) different design of eccentric should be used; i.e. duralumin eccentric on stiffened steel shaft as already suggested, or else needle type of bearing, or (b) present design of eccentric to be used, but bearings to be lapped with shaft in position, to give a good bearing surface. (2) Re-design of ball valve and seating necessary to obviate wear of seating and consequent alteration in ball valve movement. It has been found that with the present design, the sharp edge of the seating very quickly wears away with consequent increase of ball valve movement and oscillation of the plunger. (3) Re-design of camshaft and valve springs to eliminate valve bounce and valve surge by using very high rating valve springs and a low spring load with valve on its seat, together with a suitable camshaft - in this way it should be possible with the aid of automatic tappets to eliminate all valve noise. We think this re-design of camshaft to be urgently necessary. Such a combination of camshaft and springs has been found very successful on aero work. HS{Lord Ernest Hives - Chair}/C.S.Steadman. 27.2.34. | ||