CYLINDER WEAR

Evening Star, Issue 25425, 5 March 1945, Page 6

CYLINDER WEAR

LARGELY CUE TO CORROSION ADVICE TO MOTORISTS Owing to war conditions, particularly lack of replacement tyres, many motor cars in this country are now out of service, and, in many instances, the engines are not run occasionally to keep a film of protecting oil on cylinder walls, etc. Such neglect can have harmful effects from carbonic acid' corrosion, which is likely to set up in an unused engine. In this connection, says the ' Dunlop Bulletin,' it is of interest to cite the outcome of a very informative test, conf ducted a few years ago by one of. the major oil companies of America, to determine the cause of cylinder wear. The extensive test was carried out with six representative makes of cars, and 100.000 miles were travelled over all kinds of roads and in all _ kinds of climatic conditions so as to get conditions paralleling average usage. A speed of approximately 40 miles per hour was maintained l by relays of drivers, so that the engines were stopped only about every 5,000 miles for adjustment. As the result, of this test the average cylinder wear for the whole 100,000 miles was only fiveeighths of one thousandth of an inch. The test, plotted against a confirmatory one where the cylinders were so corroded that they had to be reground after running only one mile per day for a year (365 miles), proved that carbonic acid corrosion was about the only cause of wear, and not attrition as previously assilmed l . Technicians now know this, and that the cure therefore for cylinder wear is to maintain, when possible, the wall temperature of the cylinders at about 85 deg. Cent. (185 deg. Fahr.). From this it will be seen how important it is that the engines of automobiles out of commission should be run fairly frequently until the water in the cooling system nearly reaches boiling point (212 deg. Fahr.) to minimise risk of corrosion of cylinder walls. .