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).
Responses from the Chief Engineers of Sunbeam and Vauxhall to an article about the 'Battle of the Valves'.
| Identifier | ExFiles\Box 31\2\ Scan078 | |
| Date | 1st August 1914 | |
| THE AUTOCAR, August 1st, 1914. 229 The Battle of the Valves. Replies by the Chief Engineers and Designers of the Sunbeam and Vauxhall Companies to Mr. C. Y. Knight's Article under the above title, published in "The Autocar" of July 18th. By L. Coatalen (Sunbeam). AS Mr. C. V.{VIENNA} Knight deals specially with the Sunbeam car I am tempted to send a reply to his article in The Autocar of July 18th. Eliminating other factors, and confining the issue to Minerva and Sunbeam, Mr. Knight would have us believe that the sleeve valve type of engine has been demonstrated to be superior to the poppet valve type for racing cars, that is for speed. I make this point, since Mr. Knight seems to regard the Tourist Trophy race as a speed race alone, and talks of 59 m.p.h. as the ultima Thule of racing cars. But the Tourist Trophy race was something very different, and tested every part of the chassis, the valves being only one item. It is not fair, therefore, to ascribe the undoubtedly brilliant success of the Minerva team to the valve system alone. But even on speed Mr. Knight makes a great mistake when he infers that only one of the Sunbeam cars was faster than the two fastest Minervas. Both Sunbeams were much faster, but were quite satisfied to lead by a small, though sufficient, margin. As a matter of fact, they were never let out to their full extent. I have the highest opinion of Mr. Knight as a designer, but this very quality unfits him, in my opinion, to rank as a fair judge on the Minerva performance. Surely there is some credit due to the chassis designer and builder. Success in the Tourist Trophy race was as much bound up with the chassis as with the engine. Indeed, in the Sunbeam experience more so, as the two Sunbeam failures were not valve failures, and had slide valves been used the same thing would have happened. It is, therefore, not logical to attribute the Minerva success to the use of sleeve valve motors and the failure of others to their non-use. On the other hand, I should like to know what really happened to Porporato's Minerva, which, I understand, did more than the last lap firing on two cylinders only. Furthermore, the Straker-Squire with poppet valve, was only a few seconds behind the second Minerva, and we all know that the Straker-Squire lost much time through a leaking petrol pipe. Does not this make rather a rent in Mr. Knight's cast iron theory? As a matter of fact, there is no reason really why Mr. Knight's theories should not be translated into practice. With Brooklands as a venue we are prepared to accept any reasonable challenge from him on behalf of the sleeve valve engine. We should prefer the match to be for the same distance as the Isle of Man race, and we are prepared, if Mr. Knight accepts, to give him something much more substantial by way of handicap than the six-tenths of a mile per hour which he claims to be the difference in speed between the winning Sunbeam and the nearest Minerva. By Laurence H.{Arthur M. Hanbury - Head Complaints} Pomeroy (Vauxhall). IT is doubtful if Mr. Knight is to be congratulated upon or commiserated with for raising again the battle of the valves. His article in The Autocar of July 18th is so unscientific in expression and deduction that I would like to call attention to the more glaring cases of fallacious reasoning. First let me heartily disclaim any wish to belittle the Minerva Co.'s performance in the Tourist Trophy Race. With one other exception it was the outstanding success of the race, especially as the Minerva cars were what they professed to be and nothing else. But when Mr. Knight goes on to insinuate that the above performance was due to the sleeve valve motors being used, I join issue with him. Mr. Knight's statement that of the three competitors using four overhead valves per cylinder only one car out of nine survived, means nothing in a discussion on the "battle of the valves." Sunbeams had no valve trouble, neither did Vauxhalls, and of the Humbers I believe that the valve trouble was apart from the system employed. In any case it is certain that out of the nine cars in question six had no valve trouble whatever. This alters Mr. Knight's percentage from 11% to 66% from the valve point of view. Further, I understand—Mr. Knight will correct me if I am wrong—that one Minerva engine broke a sleeve valve and only just got home. If this be so the percentage of genuine finishers from the sleeve valve point of view becomes 66% also. But this talk of percentages means little any way. The obvious and outstanding characteristics of the sleeve valve engines in the T.T. Race were their oil consumption and noise. To object to four valves per cylinder on the score of complication "increasing the possibilities of trouble by 100%," as Mr. Knight puts it, is just as logical as the old objection to a six-cylinder engine that it was six times as likely to give trouble as a single cylinder. I would assure Mr. Knight that the valve system which he criticises, or any other valve system, is only a possible 1% of the things that can and do give trouble in the development of every racing car that has ever done anything. It is a striking and instructive fact that the Mercédès Co., who have for some years built engines under Mr. Knight's patents, did not enter sleeve valve engines in the recent Grand Prix, and further entered cars fitted with the much-abused four valves per cylinder construction, and yet even the Minerva performance pales into insignificance beside that of the Mercédès. I think I am safe to presume that if the Mercédès Co. with all its wealth of capital, experimental and technical resources, had thought the sleeve valve engine the best engine to use they would have used it. Now to discuss for a space Mr. Knight's apologia for the obvious deficiencies of the Minerva lubricating system. He tells us that in the preliminary trials the existing lubricating system was perfectly capable of withstanding "the worst gruelling that could be given on level roads," but that the climb up Snaefell demonstrated its insufficiency for six miles of mountain climbing. A lubrication system that proves efficient at 90 m.p.h. on level stretches, but which is found out by about seven minutes hill-climbing, seems to point to other things being at fault. Dr. Riedler in his work on the "Scientific Determination of the Merits of [Handwritten in margin] X497 | ||