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).
Proposal for further tests on engine valve lift and air flow to improve volumetric efficiency and power.
| Identifier | WestWitteringFiles\S\September1928-October1928\ Scan190 | |
| Date | 26th October 1928 guessed | |
| contd :- -4- and secondly the appreciable increase in flow when the valve is lifted above the standard amount. The std. lift is .429 and these diagrams shew that by increasing the valve lift to .600 the air flow is increased by 27 1/2 % for this particular pressure difference. It is chiefly for this latter point in which the interest lies because it indicates the possibility of increasing the volumetric efficiency of the SS.{S. Smith} engine by using slightly higher valve lift. These static tests as far as they have gone have yielded the information sought, inasmuch as they suggest a further test on this question of valve lift which should be made to approximate more nearly to the conditions of working on an engine. We therefore propose to make a simple and quick test on one cyl. of the SS.{S. Smith} by altering the rocker centre to give an increased lift to the valve. We shall then take the compression pressure of this cyl. at different speeds and compare with a cyl. having the normal lift. From the compression pressure we should see if there was any possibility of increasing the power. We wish to make further tests on the air flow valve rig as we think we can obtain useful information with regard to valve ports and valve shapes both with regard to our car engines and aero engines. One test we wish to make is to determine if the turbulent type head offers greater impedance to the incoming charge due to the closeness of the walls to the valve head than the old type open head. We should also be able to estimate the resistance offered by the carburetter. contd :- | ||