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).
Technical article discussing lubrication issues, including foreign matter in oil, the preference of oil over grease, and power loss from unlubricated brakes.
| Identifier | ExFiles\Box 76\4\ scan0125 | |
| Date | 2nd September 1913 guessed | |
| (e) FOREIGN MATTER.—Too much care cannot be taken to exclude foreign matter from an oiling system, and a sufficient sump should always be placed, so that any grit or worn particles of material can fall into this sump in such a manner that they will not become dislodged by the jolting of a car, and again enter the oil circulation. This applies also to the gear box and differential casing, and, bearing this in mind, it is generally advisable to use a lubricant of such viscosity that solid matter will not be held in suspension in the lubricant itself, but will promptly fall to the bottom of the sump. In some cars, owing to defective design of the bearings themselves, the user of such a car is unable to employ a lubricant which will comply with these conditions, as when a thin oil is introduced into the gear box or the axle, it gives trouble by creeping through the bearings and dropping on to the road or the brake drums. Mr. Alexander Duckham some time ago carried out some useful and important tests, which were reported in The Autocar of December 18th, 1909, showing the loss of power which was occasioned by the adoption of grease lubrication, and, personally, I never employ any other lubricant except engine oil for this purpose, with most satisfactory results. Oil Preferred to Grease. When the gear box bearings are properly designed oil is by far the best lubricant for both shafts and teeth, as it is thrown up in a continual stream and always goes where it is required. On the other hand, with the grease lubricated box, the gear teeth cut a passage through the grease and thereafter fare very badly with regard to an adequate supply of further lubricant. Grease also has a nasty habit of retaining any particles of grit or chipped metal in suspension, which is continually churned round and does further damage to the working parts. Impurities in the oil are sometimes a source of trouble to the motorist. These may consist of water, acids, or small pieces of fluff, which are sometimes passed to the oil from the refineries. Fluff is seldom found in canned oils, but where oil is handled in barrels or drums it is sometimes met with and can only be accounted for through carelessness with the packages. Sometimes a drum may be left with the stopper out, and a piece of waste inserted; this is a very dangerous practice, as the waste is apt to enter the drum to be eventually encountered in the oil strainer of the engine. Oil in the correct place is what is aimed at in an efficient system of lubrication, but this ideal is sometimes attended with the evil results of distributing the oil in other places as well. Allusion has already been made to oil throwing into the cylinders, and creeping to the brake drums, and the latter fault in particular, in addition to causing loss of lubricant resulting in a dirty car, is also a matter of considerable danger to the occupants of the car itself. Greasy brakes can never be relied upon, and although a certain amount of oil is often desirable on the brake drums of many cars, a continuous excess of lubricant makes the brakes erratic and useless at critical moments. A Cause of Loss of Power. Many motorists are unaware of the considerable loss of power which occurs in some types of unlubricated brake drums when the brake shoes hang upon the drums through insufficient disengagement. Those who wish to get the best results from their cars should pay some attention to the lubrication of the joints of the brake shoes and their actuating mechanism, as this detail is often overlooked, and in many cases insufficient provision is made for the introduction of the necessary lubricant. The multifarious small details which go to complete the construction of a modern chassis have fortunately received the careful consideration of designers in the modern type of machines, and such working parts as spring shackles are now usually fitted with efficient lubricators. It is much cheaper to buy oil than to pay heavy repair bills, and one does not suffer the inconvenience of continually having the car laid up when careful attention is paid to all the details which require lubrication, both by hand and by pump. Many makers pride themselves upon the small consumption of lubricating oil that their engines require, but it cannot be supposed that a certain quantity of oil, continuously used over and over again for lubricating parts which run at high temperatures, can maintain its lubricating properties for a great length of time. In gas engine practice one does not usually care to employ an oil which has been used for cylinder lubrication a second time for the same purpose, although it may do quite well for shaft bearings. Some interesting figures were given some time ago by Mr. F.{Mr Friese} S. Bennett of the mileage run by an engine in which he is interested upon a certain quantity of oil, and these figures were backed up by cylinder measurements showing an extraordinarily small amount of wear. This, however, should be taken as an exceptional case, and I should personally prefer to incur a larger expenditure upon an adequate supply of clean fresh oil than to make a small saving in this respect at the risk of spoiling an engine. [Image Caption] One of the first 15 h.p. Metallurgique-Dietrich chassis to be fitted with a cabriolet body. This car has just been supplied to Mr. F.{Mr Friese} C. Heffer by Messrs. Chas. Jarrott and Letts, Ltd. | ||