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 responding to queries about engine specifications, including valve bounce and spring loadings.
| Identifier | ExFiles\Box 88\4\ scan0090 | |
| Date | 30th July 1934 | |
| X7060 Exptl. Dept. HS{Lord Ernest Hives - Chair}/Smth.24/KW. 30th July, 1934. Major F.B. Halford, 8 & 9, Golden Square, LONDON, W.1. Dear Sir, We beg to thank you for yours of the 28th inst., and in reply to your queries have pleasure in forwarding the following information, (1) We wish to be free of valve bounce up to 5000 r.p.m. with the present springs. These springs give a seat loading of 56 lbs. and a rating of 115 lbs/inch. (2) At 5000 r.p.m. the maximum negative acceleration is 5,850 ft/sec.2. This, of course, occurs at maximum lift (.400 ins.). At the 1st changeover point the negative acceleration is 2,925 ft/sec2. At these two points the spring loadings are 102 lbs. and 64 1/2 lbs. respectively, so that theoretically the valve should bounce on the nose of the cam. (3) We should prefer to retain the clearance adjusting screw. We wish to minimise noise on starting up by giving the gear the smallest practicable initial clearance. (4) We have no objection to the inner member of the hydraulic unit being integral with the rocker. (5) We enclose a blue print which we think will give you the information you require. We are very pleased to hear that you consider that modifications permitting an engine speed of 5000 r.p.m. are possible, and shall await your suggestions with great interest. Yours faithfully, FOR ROLLS-ROYCE LTD. | ||