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).
The specifications for air valve and suction chamber units.
| Identifier | ExFiles\Box 66a\1\ scan0036 | |
| Date | 28th January 1925 | |
| R.R. 493A (50B) (D.B. 175 25-9-24) J.H.D. EXPERIMENTAL REPORT. -6- Expl. No. REF Hs{Lord Ernest Hives - Chair}/ACL/LG28.1.25. AIR VALVE AND SUCTION CHAMBER UNITS :- Suction chamber E.73036 - full instructions on drawing. When suction chamber is screwed into its carburetter body, it should bed down firmly on the aluminium washer E.71461 and the lower part of the smaller bore should not bind in the bore of the spray chamber as this would probably cause distortion and impair the free action of the air piston. Suction chamber cover. E.71530. It is important that the metal-to-metal joint between this cover and the suction chamber is perfectly air-tight. Suction chamber nut. This nut must not be a tight fit on the thread and must hold the suction chamber cover squarely on its seating to prevent any air leak between the cover and suction chamber. Air valve. See Arrgt. Drg. E.72182. To be ground to clearances shown. It must work freely in the suction chamber. There are three air leak holes .015" dia. drilled in the piston cover. There should be approximately .0015" clearance on the diameter between the piston and the suction chamber on both the large and small bores. Diaphragm. It is very important for the successful working of the carburetter that the diaphragm E.72173 is set in its correct position on the connecting rod E.72175. The top side of the diaphragm must be level with the bottom of the diaphragm ports which are in the high speed throat. See attached print. When the diaphragm is correctly adjusted and after it has been tested on the engine. it should contd :- | ||