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).
Potential engine and chassis improvements for a new car model.
| Identifier | ExFiles\Box 5\4\ 04-page213 | |
| Date | 27th April 1929 | |
| E.{Mr Elliott - Chief Engineer} DA.{Bernard Day - Chassis Design} Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} from R.{Sir Henry Royce} c. to SG.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to PN.{Mr Northey} LUS. 75080 RS{Sir Henry Royce's Secretary}/M27.4.29. X.5770 20 HP X.5050 This will now become the 25 HP. if bored 3.250" and 25.3 HP. if bored 3.250. The new head (alux;) has 1.35 valves instead of 1.25 (cast iron). The throttle, uptake, induction passage had already been made larger. The exhaust is more efficient and can easily be made more silent and like SS.{S. Smith} I do not propose that we wait for the new hypoid rear axle or the new front axle. My impression is that we should realise 20% to 25% increase over the present standard in average torque and max. HP. CARBURETTOR. This will need to be proportionately larger - i.e. about 25% increase in area of low speed and high speed venturi and extra air valve (over old pattern.) I believe we had a larger air valve which was not adopted. Longer inlet cams and rollerless tappets should be fitted if more power or speed will result. The gear has gone lower by the smaller wheels. This should not be reduced anymore or the engine will be over speed unless we get the valves to follow the cams up to 4000 revs., then I think we could reduce. CUTOUT. Perhaps this car would better please if it had a cutout always fitted. It is very good here when one wants to get over the ground quickly. ONE QUICK MOVE. My telegram suggests that all the moves for power (and the long frame for appearance) should be introduced at one time. contd :- | ||