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).
Road and bench tests for Phantom III petrol drain ball valves following complaints of carbonising.
| Identifier | ExFiles\Box 93\2\ scan0221 | |
| Date | 1st February 1938 | |
| To By.{R.W. Bailey - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Mx.{John H Maddocks - Chief Proving Officer} c. to Rm{William Robotham - Chief Engineer}/G.H. file 308 Rm{William Robotham - Chief Engineer}/GR.{George Ratcliffe}9/JH.1.2.38. PHANTOM III PETROL DRAIN BALL VALVES. Complaint of ball valves carbonising. The following road and bench tests were carried out on 35.EX, the object being to place a single ball valve in a cooler position than the existing dual ball valves. It has been suggested that a permanent bleed would answer the problem, this is not so because the fuel supply is at its maximum pressure of feed with the engine stationary i.e. with electric pumps. A permanent bleed for draining is only applicable when the fuel pump is mechanically driven from the engine. Further disadvantages of a permanent bleed are the bad effects on idling, distribution and cold starting. We therefore adhered to a ball drain valve. This was detailed to Rm.{William Robotham - Chief Engineer}477/8 and is situated at the bottom end of the manifold drain pipe. The conversion consists of removing both balls from their present position and placing one only in the body Rm.{William Robotham - Chief Engineer}477/8 having first sweated the latter at the bottom of the drain pipe; a separate pipe is then required to couple up with the existing floatchamber drain and also a blank nut for the centre of the manifold drain. Tests on the road show that with the standard layout the ball valves drop off their seatings at 8 m.p.h. and seat again at 16 m.p.h. full throttle. The single ball valve scheme gave 8 m.p.h. and seated again at 18 m.p.h. open and closed respectively at full throttle. Flow tests at maximum flooding with complete assembly on car and high pressure petrol pumps gave the following figures. | ||