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).
Technical memo discussing issues and proposed improvements for the valve rocker lubrication system.
| Identifier | ExFiles\Box 13\2\ 02-page044 | |
| Date | 1st February 1929 | |
| R.{Sir Henry Royce} from E.{Mr Elliott - Chief Engineer} c. to SG.{Arthur F. Sidgreaves - MD} Hs.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} 77090 E1/M6.2.29. X.7060 X.7090 SS.{S. Smith} VALVE ROCKER LUBRICATION. Regarding the above we do not altogether like the proposed small flats on the rocker shaft as they are in effect a number of jets along a pipe spouting oil. The oil distribution is likely to be uneven due to fall of pressure along the line and also the restricted slot shaped area formed by the flat is liable to stoppage by particles of solid matter. There is no doubt that we want to add to the oil feed on the push rod side of the rockers under all conditions, however. Blueprints Lec.2663/4 attached deal with further proposals. The former is a scheme formerly suggested to Derby to alter the balance of the oil feed. It shews the whole of the oil collected in the annulus between the ends of the rocker bushes diverted to the push rod side and further augmented by placing the feed holes in the rocker shaft as near the ends of the bushes as possible. The valve end of the rocker is supplied from a row of holes approx. half way along one of the bushes feeding an annulus in the bore of the rocker. The oil flow in this direction can be increased by duplicating the scheme and thus making the rocker symmetrical, or by substituting an annular groove for the row of holes. Lec.2664 is an attempt to carry the low pressure oil right out to the ball ends on the rockers. It appears to act as a rudimentary cushioning scheme and the oil should get there when the engine is started up from cold. The amount of oil allowed to escape can be controlled by the clearance A, or the amount of sphere left on the ball. It is comparatively independent of the variations in the tappet clearance B. If it is considered undesirable to have an oil hole at the point of max. bearing pressure perhaps 3 or 4 radial holes C.C. might be better. (SEE ORIGINAL FOR SKETCH). It is well known that when the engine is started up from cold all parts under pressure receive oil almost immediately, but other parts depending on oil escaping from the various bearings receive practically none until the oil thins. They depend upon residual oiling for the short period of warming up. contd :- | ||