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).
Modifying the Phantom II's heavy exhaust valves to reduce noise.
| Identifier | ExFiles\Box 131\4\ scan0354 | |
| Date | 25th June 1937 | |
| 1103 To Hs.{Lord Ernest Hives - Chair} from Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} c. Rm.{William Robotham - Chief Engineer} c. E.{Mr Elliott - Chief Engineer} c. By.{R.W. Bailey - Chief Engineer} Cricklewood June 25th 1937 PHANTOM II. Depot Modification to Heavy Exhaust Valves to overcome difficulty of quietening valves in service. In conjunction with the Cricklewood Depot the heavy exhaust valve E.85505 fitted to Chassis 50 in O.2. series to T.2. series, has been reduced in weight 1 oz. by reducing the stem from .460" to .433" and reducing the thickness of the head by judicious grinding. The E.85506 valve guide made to have a bore of .4335 in place of .4630. The cost of grinding 6-E.85505 valves as mentioned is with bonus time £1. 3. 1. These valves and guides have been fitted to three cars, 68.MY, 154 MY, and 22 PY. In each case the Depot have had no difficulty in producing quiet valves and the job has gone off test with less difficulties than previously. We have still to wait for development in service usually 2000 miles for recurrent valve chatter. In order not to do anything which the administration would not agree with I am sending sections of the exhaust valve fitted prior to O.2. series E.78493 and of the E.85505 valve, after lightening. A sectioned heavy valve will be sent later for comparison. If this meets with approval I would suggest a Standardisation sheet signed by yourself, Expl. and Design Depts. Rm{William Robotham - Chief Engineer}/GWH.{George W. Hancock - Head Chateauroux} | ||