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).
Modifications and tests on carburetter and camshaft for the 7 CA model, including issues with petrol quality.
| Identifier | ExFiles\Box 35\2\ scan 054 | |
| Date | 18th February 1919 | |
| H.H. 235a (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. -2- EH1/LG18.2.19. Contd. The carburetter on 7 CA has also been made larger. The low speed throat has been altered but the high speed throat has been bored out to .9 to 1.050 - this was done on an existing casting. The ports in the air valve have also been made larger. HP. tests taken on the standard car engine shewed that it is in the carburetter where one can chiefly increase the HP. We have found that the standard carburetter opened out like 7 CA makes a better running engine than if we fixed one of the White Knave type which was a larger dia. low speed throat. So far as we have not recommended the increase in the size of the carburetter because of the poor quality of petrol it might give customers trouble. 7-CA is fitted with a camshaft which has "Eagle" cams .4 lift. It has the improved rockers and tappets. We have not yet been able to make a car camshaft with the cams which were got out for the car because of the difficulty with the camshaft grinder. This, we think, is now being overcome. EH. | ||