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).
Causes and potential cures for 'spitting in the silencer'.
| Identifier | ExFiles\Box 6\7\ 07-page103 | |
| Date | 20th November 1930 | |
| X5230. To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/AJL. c. to JS.{Mr Johnson's Secretary} c. to WDT. c. to A.{Mr Adams} c. to RV. Ref: Hs{Lord Ernest Hives - Chair}/AJL.1/WJ.20.11.30. X5230 X5230 SPITTING IN THE SILENCER. We are continually working to find the cause and cure for spitting in the silencer. Tests we have done in the past have shown us several factors which effect the complaint in some degree; we have demonstrated the following points to be guarded against, all of which emphasise the trouble :- (1) Badly fitting throttle. (2) Controls not allowing throttle to close fully when accelerator pedal is released. (3) Air leaks in the induction system. (4) Weak low speed jet setting. Even when all these points are guarded against and corrected we still have some cars which are very good and others which are bad. We have so far been unable to find out exactly why. Tests carried out previously on Phantom 1 cars indicated that if we could supply a very rich mixture at small throttle openings or use an additional jet to come into operation when the throttle is just closing the spitting could be eliminated. Working on these lines we have richened up the mixture at very low engine speeds (small throttle openings) | ||