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 from The Rover Company Ltd to W.A. Robotham of Rolls-Royce discussing new engine performance issues.
| Identifier | ExFiles\Box 127\2\ scan0158 | |
| Date | 16th December 1940 | |
| TELEGRAMS: ROVER.COVENTRY. THE ROVER COMPANY LTD NEW METEOR WORKS COVENTRY TELEPHONE Nº 88081. YOUR REF. Rm{William Robotham - Chief Engineer}/14/ML. OUR REF. MCW/JM.{Mr Morley} 16th. December, 1940. W. A.{Mr Adams} Robotham Esq., Messrs. Rolls-Royce, Ltd., DERBY. Dear Robotham, Many thanks for your letter of the 4th. which I am sorry not to have answered before. The new car engine is on the road, but has not done much more than 1,000 miles, and has probably the equivalent of about 2,000 miles carbon in it altogether because of some previous bench running. At present it pinks a little bit too much on the new Pool petrol, but looks as if a reduction in compression ratio of a quarter of a ratio, from 7½ which it is, to 7¼, would just about put it right. The engine goes on running almost continuously when treated in the way you describe, but we are very used to this occurrence as it happens on all our present cars, though perhaps not quite so badly. We were very worried about it at one time because a lot of people complained, and we did not know what the answer was, but now we find that from the customers' point of view it can be cured entirely by setting the idling to a reasonably low speed. Have you any idea what actually starts ignition in this case, and why it should only happen on very low engine power outputs. We have satisfied ourselves that it is not sparking plug, and probably not exhaust valve because that should be comparatively cool under the low load conditions. We are having considerable trouble with the new engine in getting a respectable pick-up on the road. This is the first time we have tried a water heated manifold and we know very little about them. Can you give us any hints as to what you have to do with a water heated manifold in order to make it function, that you do not have to do where you have a considerable exhaust hot spot. What sort of air speed in the manifold would you say was the minimum permissible at say 1,000 r.p.m. on full throttle. All this is, of course, with one carburetter on a 4-cylinder engine. Cont'd.{John DeLooze - Company Secretary} | ||