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 and camshaft wear after endurance testing, with proposals for future tests and hardness comparisons.
| Identifier | ExFiles\Box 96\2\ scan0178 | |
| Date | 9th December 1936 | |
| -2- All the Hykro tappets, however, were in a terrible condition with flats and score marks and the camshaft in a similar condition which is scrapped. This after 4 hours endurance running, at 4000 R.P.M. - 4500 R.P.M. Fescolised tappets and the corresponding cams on the camshaft were in exactly the same condition as when fitted second hand, with slight marks across the face. Future tests include:- (a) Small base circle cam to reduce rubbing velocity with Fescolised and cloudburst hardened tappets. (b) Repeat run with 'Hykro' tappets. (c) Hykro camshaft and various tappets. (d) Sodium cooled exhaust valves to reduce expansion figure. (e) Bentley type of valve spring with reduced loading on cams as compared with existing Ph.III. double springs. As we do not know of anything as yet which can replace the Fescol tappet, 35-EX. will go on 15,000 miles test with these tappets. The hardness figures of the various tappets are as follows - Brinell S/ZN. std. hardened and cloudburst 950 Carburized Hykro. 825 - 850 Carburized Hykro and cloudburst. 925 - 950 Chromium plating. Approx. 1000 Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} | ||