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).
Proposed alterations to cam forms and valve timing for Scheme 723.
| Identifier | ExFiles\Box 43\3\ Scan058 | |
| Date | 21th July 1926 | |
| To BY.{R.W. Bailey - Chief Engineer} from E.{Mr Elliott - Chief Engineer} c. to BJ. R.{Sir Henry Royce} c. to RG.{Mr Rowledge} Hs.{Lord Ernest Hives - Chair} X4003 E2/M21.7.26. F.10. CAM FORMS. X.4003 RE. SCHEME 723. X.3822 X.1770 In confirmation of R's verbal instructions during visit of Hs.{Lord Ernest Hives - Chair} and BY.{R.W. Bailey - Chief Engineer} yesterday, new valve lift curves should be got out immediately at Derby having increased acceleration of opening, higher lift, and longer duration of opening of exhaust. These should be used with the greater overlap on the timing previously instructed. The dia. of the rocker roller should be increased to assist in obtaining a highest value for the acceleration of opening possible within the limits of the maximum curvatures that can be produced on the cam grinding machine. The proposed alterations are shewn in the following table :- PRESENT. PROPOSED. Acceleration of opening. .0028" per div per div. .0035" per div per div. Valve lift. .415" .455" Duration of lift: exhaust. 62 div 64 div " " inlet. 62 div 62 div Diameter of roller. .8 .95 The new timing diagrams obtained with these figures, and with 108° between the cams on the camshafts instead of 112° is as follows :- (This angle has to be altered from 106° given in R's telegram of 19th. inst. to 108° to keep overlap the same with 4° longer exhaust cam.) E.{Mr Elliott - Chief Engineer} (SEE ORIGINAL FOR - NEW TIMING). | ||