CYLINDER WEAR

Rotorua Morning Post, Volume 2, Issue 290, 2 August 1932, Page 2

CYLINDER WEAR

DUE TO MANY CAUSES. The own'er of a car who finds that his cylinders. wear out quicker than his tyres may be forgiven for an i,nclination to revile the manufacturers, says an article in a recent issue of The Motor. if he is a motorist of considerable experience he may think that the art of making cars has not kept 'pace with that of tyre production. As many owners know to their cost, we have gone through' a period of rapid cylinder wear with popular . makes of car, which we hope will never recur. We have been inundated with complaints referring to cars a few years old. Some there are who hold that one reason was the use of unsuitable castings which' were unable to withstand the higher engine speeds now obtained, a point which, at any rate, we are assured has been remedied. Others lay the blame upon the carelessness of the user who does not appreciate that the modern engine is a piece of machinery worthy of more than ordinary care. We should attribute rapid cylinder wear to a number of causes rather than to any particular one. Here are a few points for consideration. Co-incident with this trouble is the employment of aluminium pistons, which, in turn, have enabled a greatly increased output to be obtained, coupled with higher engine speeds. Much of the increased wear of cylinders may be due to the use of a softer piston metal (compared with cast iron), in which hard particles of abrasive material may become embedded, with a consequent lapping action upon the cylinder walls. Our engines have become smaller in size, for a given task, and cruising speeds have gone up; the amount of fullthrottle running has thereby increased, so adding to the Joad on the pistons and raising the working temperatures. Again, stranglers have come into common use to give a rich starting mixture, the eff'ect of which is to wash the cylinder walls before the oil circulates. Need for Resarch. Notwithstanding the disadvantages under which modern engines operafe, there is abundant evidence that, with careful use, such as, it is admitted, was not so essential in the days of cast iron pistons, and low power outputs, very long cylinder life can be obtained. It is important to remember that when two metal surfaces are in rubbing contact at high speed, wear is bound to occur, and the only way to minimise that wear is to separate the surfaces by a film of oil. Thus, the oil must be given time to circulate before tbese surfaces are moving over each other at any speed. One of the virtues of upper cylinder lubrication should be apparent in this respect, while air cleaners and oil strainers also seem to be desirable requirements in modern high-speed light-weight engines. It should also be mentioned that liners would provide harder bores of a uniform thickness less subject to distortion when hsated. •Unfortunately, this is a subject in which there has been far too little research. Car design has progressed greatly in the last ten years, but not always in the direction of providing durability commensurate with the greater power outpqt and higher speeds available which are placed in the hands of those who will not trouble to treat their car as a thoroughbred rather than as a common hack. Considerable improvement has now been effected. Given reasonable care in use, rapid cylinder wear should not appear in 1932 cars.