ENGINE WEAR.

Auckland Star, Volume LXI, Issue 129, 3 June 1930, Page 15

ENGINE WEAR.

EFFORTS TO SOLVE PROBLEM

MANUFACTURERS CAUTIOUS,

Increased engine speeds have in recent years directed attention to the urgent necessity of reducing wear as well j as facilitating readjustment and replacement of wearing parts of power units. That there has been considerable response to this need was to be easily gathered from a study of many of the exhibit at Olympia in November last. There appears, however, to be a tendency among a number of engine manufacturers to overlookthe means now available for reducing reconditioning costs. From the manufacturing point of view it is, of course, necessary to study the question of production costs very carefully, and before introducing any departures from previous standard practice their value to the user in relation to any increase in purchase price they would involve must be fully considered. In these days of keen price competition a cautious policy in this respect is likely to be followed by the majority of makers so long as users regard low first costs as of primary importance. It is evident, however, that experienced operators are realising more and more that it is more economical to pay a higher price for their machines if they can be kept longer in service between overhauls, and if necessary repairs can be executed in a shorter time than before.

For the reduction of engine wear there appears to be greater possibilities in the use of better wearing materials than by the improvement of lubrication. The parts chiefly concerned are those where the engine power is first applied, namely, the cylinder walls and the connecting rod and crankshaft bearings. Promising results have been obtained in this direction by the use of renewable cylinder liners of steel and centrifugally cast iron, which, in addition, avoid reboring and fitting oversize pistons when wear occurs, ball and roller crankshaft bearings that require minimum lubrication and special steels case-hardened without distortion by the nitriding process. Of these the first has already found considerable favour among British and Continental manufacturers; the second has been adopted with success on the Continent either by the use of a built-up crankshaft or by employing special antifriction bearings adaptable to crankshafts machined from the solid; the third, so far, has been adopted experimentally by both British and foreign engine makers, but it is difficult to suggest any reasons why its advantages should not be fully realised. All these means of reducing wear admittedly involve higher production cost, but, even so, the opinion is expressed that their adoption should receive more serious consideration as preferential alternatives to older practices which at present give so much cause for anxiety to maintenance engineers.