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).
Noise issues with the valve springs on the 20/25HP engine and proposing a solution.
| Identifier | ExFiles\Box 56\2\ Scan102 | |
| Date | 19th September 1930 | |
| Hs{Lord Ernest Hives - Chair} C-Sect. from Mx.{John H Maddocks - Chief Proving Officer} Mx{John H Maddocks - Chief Proving Officer}1/T19.9.30 VALVE SPRINGS The 20/25HP engine gives trouble on test, due to two noises from the valve mechanism, one is "swishing" or "dithering" which occurs at approximately 40 m.p.h. this being equivalent to 2000 r.p.m. The other is tapping when running light. Apart from these two features the valve mechanism on the 20/25HP is very quiet indeed since the introduction of the increased oiling. We can overcome both the features we are complaining of by closing in the bottom coil of the spring and definitely locating it on the bottom washer. The drawing dimensions permit of .025 to .040 clearance in diameter at this point, and we are afraid in a good many cases in actual practice, that even this clearance is often exceeded. Can we have valve springs definitely located as a standard measure at both top and bottom? Although we have no specific complaint on test of a similar nature on Phantom II chassis, we believe the Experimental Dept. have experienced trouble, and we believe the same treatment will be good on this engine. [STAMP] RECEIVED SEP 22 1930 HS{Lord Ernest Hives - Chair} [HANDWRITTEN] Mx{John H Maddocks - Chief Proving Officer} | ||