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).
Camshaft and piston tappet testing and modifications.
Identifier | ExFiles\Box 6\6\ 06-page228 | |
Date | 22th June 1937 | |
- 2 - Bm/Swdl.{Len H. Swindell}1/VS.{J. Vickers}22.6.37. Camshaft (Continued). (2) The actual shape of the siloncing toes as shown on the attached curve are shorter than designed curve, but the big error appears to be the base circle, which varies in some cases by .004-.006 as measured at the valve. This means that when set at .008, the clearance in other positions is .010-.012 and almost at the end of the low velocity siloncing toes which extends to .015 lift. (3) The second unit is now on test and is approximately the same in respect of valve noise as the first unit, and we are investigating further. Piston Tappets. (1) Following initial running in of two hours at 500-1000 R.P.M., the face of the flat-bottomed tappets as designed in S/2H were badly "scuffed", without exception. (2) Oil supply to eam face increased by drilling inlet and outlet holes in tappet chamber, but tappets still "Scuffing" as before. (3) Two hours similar running in, but on "Hi Press" oil gave improved result, but following a run of one hour at 4000 R.P.M. on Motorine C, tappets were back in original "scuffed" condition. (4) Similar tappets but with chromium plated face by R.R. started peeling. (5) Rotary movement of the tappets is not good, some being stationary. (6) Second engine is equipped with half a set of tappets in cast iron, chilled on the face and copied from Chevrolet with the push rod down into the base of the tappet. These have been produced by HFW. to Ex.96101, and after five hours running in up to 1500 R.P.M. appear to be in excellent condition with a mirror face. continued. | ||