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).
Requesting tests on Phantom III cylinder heads with reduced valve clearances to quieten operation.
| Identifier | ExFiles\Box 96\2\ scan0071 | |
| Date | 11th October 1935 | |
| To RHC.{R. H. Coverley - Production Engineer} X 354 Hs{Lord Ernest Hives - Chair}/Swd1.3/KW.11.10.35. Phantom III. We wish to carry out tests with reduced clearances between the valve stems and guides in order to see if the operation of the valve is more quiet. Will you please produce a pair of up to date cylinder heads complete with the latest self-adjusting tappets, LOP, E.86922, as per No.10 unit. Half the plungers on each head to have the normal .0015 & 1/10 clearance and half with .001 & 1/10 clearance. A Side Cylinder Head. E.86783 (S/SLV) inlet valves and E.87424 exhaust valves, also in S/SLV, with the stems copper-plated and polished to give a final diametrical clearance on the guide of .001 - .0015. B Side Cylinder Head. Valves and clearances as per No.10 unit, the exhaust valves being of KE-965. Valve springs as per No.10 unit on both heads. If the heads off No. 5 unit, which ran 10,000 miles, are in good condition, there is no reason why these should not be reconditioned and the above features incorporated. These heads could then be fitted to No.1 unit which is at present having new bearings fitted. Hs{Lord Ernest Hives - Chair}/L.H. Swindall. | ||