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).
Phantom II chassis regarding excessive valve noise and the results of a modification with lightened exhaust valves.
| Identifier | ExFiles\Box 131\2\ scan0012 | |
| Date | 13th August 1937 guessed | |
| 1113 To Rm.{William Robotham - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} c. to MX.{John H Maddocks - Chief Proving Officer} Cricklewood Aug. 12th. PHANTOM II. Lightened Exhaust Valves. Cricklewood Modification. I have followed one of these cases through chassis 125-RY, owner Gee. This car came in for excessive valve noise. I tried the car in the condition it arrived at Cricklewood. Engine hot. Idling, valve noise bad, there was also a bad camshaft knock. On the road, top gear, the period of valve clatter under load came on a 35 m.p.h. increased at 40 m.p.h. dies out and came at 45 pronounced up to 70 m.p.h. On the over run it was worse 70-45 40 - 30 m.p.h. I tried the car again this morning after the modified valve and guides had been fitted. Idling hot. I could not hear any valve noise. I could not hear valve noise between 35 m.p.h. and 40 m.p.h. At 50 with acute listening I could just hear the valves at 70 the noise was slightly more pronounced, but could not be heard, without listening for it. The result I should judge 95% improvement. There have been no recurrent cases after this modification up to date. RM{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} | ||