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).
Effects of Benzole mixtures and Ethyl petrol on Bentley cars.
| Identifier | ExFiles\Box 150\1\ scan0113 | |
| Date | 18th May 1936 | |
| H.{Arthur M. Hanbury - Head Complaints} COPY. BENZOLE MIXTURES AND BENTLEY CARS. With reference to your note on the above subject, as I know that this must largely apply to me, I should like to give my reasons for having advocated the use of an addition of pure benzole to overcome detonation. HD.{Mr Hayward/Mr Huddy}'s Depot Sheet No. 294 of 18.12.35, says "Ethyl petrol is....as good as No. 1 spirit mixed with 50% Benzole. Ethyl is obtainable almost everywhere; 50% Benzole mixture is, as far as we know, unobtainable except by special mixing." The above I took to mean that the only advantage of Ethyl over an addition of pure benzole was the greater ease of obtaining it, and I would add that I have always impressed upon people the uselessness of "Benzole Mixture" as supplied, and that, if benzole be adopted, it is necessary to take ones own mixture adding 33.1/3% to 50% to No. 1 petrol. My reason for not recommending the use of Ethyl has been because of its effect upon sparking plugs. When I used it myself for some little time I found that it affected the proper working of the plugs, it made the electrodes brittle, and when attempting to adjust the gaps the tips of the central electrodes would break right off. Also, on reverting to ordinary petrol the engine then detonated in a way which it would never have done had the Ethyl not been used; Benzole on the other hand seems to have quite an opposite effect. Also, there is the case of B.100-AH., C. C. Dennis. This owner complained that the engine suffered from misfiring as soon as he reached a speed of 60 m.p.h. The matter was investigated at W. and the owner in a subsequent letter to me said "R-R.{Sir Henry Royce} Works discovered at length that the cause of my trouble was due to the unsuitability of Ethyl Petrol. Otherwise all was in order. I think you should advise Bentley owners of this fact." (The underlinings are his). When I saw this Owner six months later he said that he had had no further trouble since he had discontinued to use Ethyl. St.{Capt. P. R. Strong} | ||