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).
Results of engine modifications on power output and considerations for reliability under road conditions.
| Identifier | ExFiles\Box 3\4\ 04-page157 | |
| Date | 11th January 1933 | |
| -2- Hs{Lord Ernest Hives - Chair}/Rs.{Sir Henry Royce's Secretary}1/XT.11.1.33.cont'd gives exceedingly satisfactory results, as will be seen from the power curve (2), as it raises the B.H.P. at 4250 r.p.m. by about 15, without dropping the M.E.P. at 1000 r.p.m. appreciably. A second modification consisting of increasing the clearance between the inlet valve and cylinder head on the shrouded side, as shewn on the attached print, put 74 HP. on at 4250 r.p.m. and raised the power peak to 4500 r.p.m. We do not think that it will be difficult to obtain reliability with this output under road conditions, because a genuine 90 m.p.h. is not a speed that can be used for any length of time, in fact it is doubtful whether this speed will be obtained at all on a closed car with this power output except under very favourable circumstances. So far we have had no mechanical failures on O.I. when running these power curves, but have not sufficient replacement parts as yet to attempt endurance. Hs{Lord Ernest Hives - Chair}/Bn.{W.O. Bentley / Mr Barrington} | ||