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).
Testing a 4-cylinder 2½-litre Riley engine and a proposal to develop a similar engine for the Ripplet model.
| Identifier | ExFiles\Box 128\3\ scan0048 | |
| Date | 13th June 1939 | |
| 1104 By.{R.W. Bailey - Chief Engineer} from Rm.{William Robotham - Chief Engineer} Rml3/R.13.6.39. 4-cylinder Engine. In company with Jenner, we had the opportunity of trying Mr. Skinner's 4-cylinder 2½-litre Riley. The engine is 3.17 bore by 4.725 stroke giving a displacement of 2443 c.c. The engine mounting, by modern standards, was fairly rigid, though, of course, rubber. The engine exhibited few vices, though some torque reaction was noticeable at full throttle below 15 m.p.h. At the higher speeds it was exceedingly smooth right up to 5,000 r.p.m. The secondary out of balance was not noticeable either on forward or over-run. In spite of the fact that the car weighed 30 cwts, the car had quite a good performance. Apart from the engine unit, the car was of no particular interest as the steering and suspension were poor for a 1939 model. We are so encouraged by the smoothness of this engine that we should like to go ahead with the detailing of the 3¼ x 4½ 4-cylinder engine immediately. We can use the 6-cylinder pattern modified to make the necessary castings. When fitted in the Ripplet with the junior gearbox and axle, we should expect to get a performance equal to that of the existing Ripple for two-thirds the tax. If, as proposed, we retain the existing stroke, the pistons, valves, connecting rod bearings and all the other minor components are common to the 6 and 8. Rm.{William Robotham - Chief Engineer} | ||