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).
Issue of sticking carburettor air valves on the 20/25 HP model and potential solutions.
Identifier | ExFiles\Box 102\1\ scan0204 | |
Date | 22th August 1934 | |
COPY X 5080 S/W - Wor.{Arthur Wormald - General Works Manager} from C. 6 C9/C22.8.34. Re 20/25 HP. Sticking Carburettor Air Valves. With reference to your Wor{Arthur Wormald - General Works Manager}4/R25.7.34. I found the experimental air valve which you fitted to my car quite satisfactory; it never gave any trouble and, of course, we gave specific instructions not to clean it. Of course it did not cure the popping back, but I understand it was not expected to do this. If you think it worth while, we should be pleased to arrange to fit another valve or two on to some of our own running cars so that they may be watched and reported upon. I am wondering, however, whether we cannot really cure these complaints in a simpler and less expensive manner. When H.{Arthur M. Hanbury - Head Complaints} was at Derby with Br.{T. E. Bellringer - Repair Manager} this point was discussed and E.{Mr Elliott - Chief Engineer} and the Experimental Dept. were of the opinion that many of the complaints were due to distortion of the air valve pot when screwed home into the carburetter and in the Minutes of that meeting appears the following :- "It is recommended that the Experimental Department investigate the possibility of increasing the initial clearances on both the small and large diameters and possibly deleting the small breathing hole in the top diaphragm of the carburetter" I am not certain whether the Experimental Dept. did make this investigation, but our experience is - certainly so far as the Inspecting Engineers are concerned who put right many of these complaints - that once an air valve has been given definitely sufficient clearance when the engine is very hot, the complaint does not recur. It will be interesting to know whether this is the experience of the Works also, because in that case it might be advisable to consider issuing a Depot Sheet to the effect that all air valves of the old type carburetter should be examined as and when cars come in and give a minimum clearance which you will, of course, specify, that will avoid any tendency to their sticking in future. PTO. | ||