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).
Valve spring surge, push rods, and petrol consumption/idling issues.
| Identifier | ExFiles\Box 174\3\ img302 | |
| Date | 11th July 1941 | |
| cont'd.{John DeLooze - Company Secretary} -2- geerbox. When opportunity occurs, it is considered to be well worth while investigating the possibilities of such a design and if it appears to be practical, a finalised scheme may be prepared. 3. Valve Spring Surge. The inconsistencies regarding the results obtained on the short duration camshaft were discussed. Rm{William Robotham - Chief Engineer}/TAH said that the accelerations on the short comform were as high as those on the long comform. This made the result all the more perplexing. The whole Senior Range valve gear wants reviewing as at the moment, the valves bounce at 4150 r.p.m. and whilst this is all right for the 6-cyl. it is certainly too low for the 3½ bore 8-cyl. Jnr.{Charles L. Jenner} pointed out that we were always mean on the length of valve spring which we employed; that we could gain appreciably on the valve bounce speed by drilling the inlet valves and using tubular duralumin push rods. Rm.{William Robotham - Chief Engineer} thought that tubular duralumin rods were extravagant and also not altogether desirable for a constructional point of view. Tubular steel rods could probably be produced cheaply if made in sufficient quantities. Tubular steel rods will require hydraulic tappets for the aluminium block. Jnr.{Charles L. Jenner} will see whether he thinks we can get away with steel push rods with ut hydraulic tappets from experiments previously made by Swdl.{Len H. Swindell} on the P.III. He will also look into the question of what it means to use Buick valve springs. It was also suggested that we might still have more lift than was necessary on the inlet valve we were employing, and it might be worth while trying to reduce this lift to raise the valve bounce speed. It was suggested that if chain drives eliminated valve spring surge with short duration camshaft, then it might be worth while running experiments with Reynolds chain. Jnr.{Charles L. Jenner} will investigate what design work is necessary to get this fitted. In conclusion, it was thought definitely worth while to have some valves made which would enable us to use the Buick valve springs. 4. B.V. Petrol Consumption & Idling. Progress has definitely been made on improving both the consumption and idling. The tests, however, were -Continued- | ||