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).
Modifications to 20HP valve fittings to improve oil supply to the tappets and prevent knocks.
| Identifier | ExFiles\Box 106\5\ scan0021 | |
| Date | 2nd April 1928 | |
| X5060 Mx{John H Maddocks - Chief Proving Officer}4/T2.4.28. RE 20HP. VALVE FITTINGS In an endeavour to obtain a supply of oil to the tappets much earlier than is normally obtained with a cold engine, in order to prevent tappet knocks, and also to obtain a sufficient supply of oil to the tappet rollers and pins, and valve ends to prevent wear, we carried out a modification to a rocker shaft, which has in our opinion been very effective, and has attained the desired result - this scheme could be adapted to standard production without much alteration, and will bring it in line with the 40/50, and consists of - 1. A feed to both ends of the rocker shaft instead of only the front as is now the case. 2. Feed hole to push rod side of rocker moved to register with the hole in the rocker; the sizes of the holes were varied, being - Valve Nos. 1. 2. 11. 12 - .031 dia. " " 3. 4. 9. 10 - .046 dia. " " 5. 6. 7. 8.- .062 dia. 3. Feed holes to valve side of rocker, moved to register with hole on rocker when valve is open, cutting off when valve is closed. Hole diameter remaining as standard. We have demonstrated the final result to Mr Lovesey of the Experimental Dept. | ||