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).
Letter from Packard Motor Car Company discussing carburettor design, performance, and resolutions to issues like 'spitting back'.
| Identifier | ExFiles\Box 127\1\ scan0146 | |
| Date | 10th December 1926 | |
| PACKARD MOTOR CAR COMPANY DETROIT MICHIGAN December 10th 1926. Commander W. Briggs, C/o.{Mr Oldham} Rolls-Royce Ltd., 14-15 Conduit Street, London, W.1. Your Reference CWB8/GM/261126. My dear Briggs: I was certainly glad to receive your favour of November 26 and I wish to apologize for not getting in touch with you while I was in London. I, of course, did do some chasing back and forth to the Show, but I caught a very bad cold while I was there and stayed in bed a day and a half. As I was in London a little less than five days you can see that I didn't have very much time to get around. It was a real regret that I was not able to see you. Now in regard to the questions which you ask I will advise as follows: We never had any trouble with spitting back or explosions on the muffler in the Eight due, I believe, to the fact that we never used a particularly lean mixture on this model. Up to this year, however, we always used a peculiar construction of carburettor on the Six in order to obtain maximum economy. This carburettor was practically our standard Packard design with the exception that we used a two stage jet so arranged as to thin the mixture out to the lowest practical point when driving along slowly with a cracked throttle. This two stage jet performed very satisfactorily on the pick-up and under all other driving conditions except when coasting down with the throttle close to idling position. Under these conditions the lean mixture causes an intermittent or late firing, with the undesirable results which you mention. This was not a major complaint but one which we heard often enough to cause us to abandon the two stage jet at the beginning of our present production season. We are now using the same carburettor construction on both the Six and the Eight and we are absolutely free from this trouble. CONT: | ||