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 Price's Patent Candle Company regarding lubricating oil issues, filter analysis, and proposed experiments for the Phantom III engine.
| Identifier | ExFiles\Box 144\1\ scan0262 | |
| Date | 21th November 1936 guessed | |
| PRICE'S PATENT CANDLE COMPANY LIMITED. -2- accumulate, and this trouble is most marked, of course, during humid weather. To some extent the water arises from condensation of water vapour in exhaust gases. You will be aware, of course, that water is a product of combustion of fuel. The carbon also is a product of combustion of the fuel, and whilst but little accumulates when engines are run at fairly high speeds, and at fairly high temperatures, appreciable carbon is formed, and accumulates in the lubricating oil when the vehicle is used largely for town work involving frequent stops and starts when the engine rarely reached a proper working temperature, and more-over where there is a tendency to excessive use of the rich jet for starting. As you will appreciate some cars are much more prone to this trouble than others. Judging from information within our knowledge, we would suggest that the Phantom II. is comparatively free from difficulties of this character. It does appear, however, that in the case of the Phantom III the oil supply to the hydraulic tappets is comparatively cool, at least considerably below the temperature of boiling water, so that any moisture which is held in the lubricant is not evaporated. When, therefore, the oil is "wet" it wets the filter, rendering it more or less impervious to particles in suspension, such as fine carbon. When the oil is perfectly dry the fine carbon passes quite freely through small mesh gauze such as you use in the small filter for the supply to the hydraulic tappets. This is confirmed by our Chemists examination of the small filter which you sent us as some confirmation of the troubles which you have experienced. The deposit on this filter contained an appreciable trace of water besides oily matter. The total volatiles amounted to 66.6%. The solid carbon amounted to 23.6% and other solid matter 9.8%. These points were briefly explained to Mr. Cowen and he was advised also of your promise that experiments should be carried out on a Phantom III attached to London, which experiments could be closely watched by us. It was understood that there might be some little delay before these experiments could be commenced, but in view of the new development it appears most desirable that something should be done immediately. In the first place you may be assured that the (Contd.) | ||