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).
Letter from Frank B. Halford regarding modifications to the Bentley valve gear and hydraulic rocker.
| Identifier | ExFiles\Box 88\4\ scan0088 | |
| Date | 28th July 1934 | |
| LL. Smith - See me FRANK B. HALFORD, F.R.Ae.S. DESIGNER OF AERO AND AUTOMOBILE ENGINES. Telephone Nos.: Gerrard 1217. Gerrard 1218. My Ref. FBH/EA Your Ref. Hs{Lord Ernest Hives - Chair}/Smth 11/KW. (Exp. Dept.) Messrs. Rolls Royce, Ltd., Derby. 8 & 9 GOLDEN SQUARE, LONDON, W.1. 28th. July 1934. Dear Sirs, I am in receipt of your letter of the 28th. instant, enclosing blue prints off the Bentley Valve gear. I am now laying out some modifications to the valve gear and hydraulic rocker, which I think will permit of an engine speed, without valve bounce of something over 5,000 r.p.m. Meanwhile will you kindly give me the following additional information so that I can arrive at the best compromise. (1). Up to what engine speed do you wish to eliminate valve bounce, without departing from the present valve spring. (2). What would be the maximum negative acceleration (at the valve) at the above speed? (3). In the interests of weight reduction would you object to the removal of the clearance adjusting nut, etc. The hydraulic rocker should be capable of dealing with production tolerances and wear. (4). Have you any objection to the inner member of the hydraulic unit being treated as integral with the rocker when finally assembled. (5). One scheme I am working on involves a return spring at the lower end of the push rod. Could you send me any longitudinal view showing the tappet holding down clamps - preferably indicating as well the rocker spacing, longitudinally. | ||