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).
Loud roaring sound from a Phantom III carburetter, traced to grit blocking the induction pipe drain valves.
| Identifier | ExFiles\Box 91\1\ scan0332 | |
| Date | 17th June 1936 | |
| x300 a 74 { F.F. Dood { G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Radclyffe { Scott HOTEL DE FRANCE. CHATEAUROUX. Indre. France. GWH{George W. Hancock - Head Chateauroux}/HFH{Hoppy F. Hamilton}/S/JAB. 17th June 1936 Copy sent to E To. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} 32.EX. - PHANTOM III INDUCTION PIPE During the run of the 14th inst, a loud roaring sound developed from the carburetter. This was traced to air being sucked down the float chamber vent pipe and up the petrol drain pipe under the engine. It was found that the non return ball valves in the induction pipe drains had stuck open, and being interconnected with the float chamber vent pipe, and drain, had set up a suction causing the noise. At the time, slow running tests were being carried out, and the engine failed altogether due to the over-weak mixture. Large particles of grit were found to have stuck between the ball and its seating which must have been sucked up the drain pipe. The car had previously passed over a newly made metal road which was covered with loose mud. Particles of this must have been thrown up the drain pipe and got sucked up under the ball seats. We have bent the drain pipe to face the rear of the car, so as to eliminate the possibility of this trouble reoccurring. ---------------- H.{Arthur M. Hanbury - Head Complaints} Hamilton GWH{George W. Hancock - Head Chateauroux}/HFH.{Hoppy F. Hamilton} | ||