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).
Engine performance issues like misfiring, valve bounce, and potential component replacements.
| Identifier | ExFiles\Box 108\1\ scan0404 | |
| Date | 23th February 1938 | |
| -2- Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell}11/JH.23.2.38. misfiring and popping. Making allowance for 5% fast speedometer then the above speeds are 3660 and 4275 r.p.m. respectively. We note that in your latest daily report that there is a bad valve bounce at 82 m.p.h. since fitting the larger tyres, allowing the speedometer 5% fast then correctly this is approx. 78 m.p.h. or 4,000 r.p.m. We know that there is a period in the front timing case around 3,500 r.p.m. and wonder if it is this period that is mistaken for the valve gear. We should like to know what length the valve springs are when in the valve closed position. When fitting the old thin push rods for test (a) in conjunction with old type bottom tappets, care should be taken to see that the push rods go in the proper housing as it is easy to get them wedged in the side, as accidentally done by us on one unit with disastrous results. Since fitting the new AC filter has the oil cleanliness improved ? Rm{William Robotham - Chief Engineer}/Swdl.{Len H. Swindell} P.S. Since writing this memo. Rm.{William Robotham - Chief Engineer} has been in communication with you regarding valve stretch and we are in consequence sending out 6 new exhaust valves, the existing to be removed and returned to us. We suspect sinkage on the seats rather than valve stretch, will you therefore check when the head is removed. | ||