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Show islfCYUNDER OR PISTON RING? WTien Engine Lacks Power and Compression Is Poor Make Examination. IB! ERWlS GREER. Present Orcer Collfc- of Automotive Knglnter'.nit. CWc.igo.) There Is nothing mysterious . nlnuit piston rinjs used In automobile en-fines, en-fines, even though rep:ilrmen will tell you that new rin.es of a certain sort elevate your engine Into some new 5;ate In which It produces twice ns each power and speed as before. There Is a rood deal of misinformation misinforma-tion about piston rings, and because of It automobile owners spend millions each year for such parts. In many cases getting no results from the expenditure. ex-penditure. Piston rinss are supposed to pack the cylinder, so that the fas does not lesk downward and oil upward. In order to be an Ideal device It must do this without exerting too much pressure pres-sure against the cylinder wall, and the pressure must be evenly distributed distrib-uted all arntind. The rim must fit the cylinder perfectly: It must fit Its rrooves In the p!ton so that It will be neither too tight nor too loose-Find loose-Find Cause of Trouble. Such piston rings will ran perhaps 10.000 or 30.tV0 miles, but a time must come when the rings no longer make a gas-tight Joint. It then Is necessary to find out why the rings no longer Et well. The average repair man will tell you that when wear takes place only the rings become be-come worn, so that all that Is necessary neces-sary to p'jt the engine In first-class shape Is to replace the piston rings. How the repair man knows Is one of the mysteries of this world. The fact ls thai no one can tell whether the rlar are worn or whether the cylinders cylin-ders are worn, or just what the condition con-dition of these parts Is unless the parts themselves are eraniini-d and EF-asurei. This explains a great deal of tron-hte tron-hte owners have, because so-enlled oversize rings were Installed In the frlimlers. In the first place the cylinders cyl-inders should he made true, either by ?r;ndin or some other process, and WW rings ohtained to fit the new tore. In this way only can one he fire of a perfect fit. To say that new lugs will lap themselves Into an oval tare Is wrong, for they will not. nor will new rins In worn cylinders take the shape presenter by score marks r hard spots In the cylinder metal. Rmgj Do Not Fit. Wien your engine lacks power, hen the compression la poor vben ; pumps oil and uses too much fuel. usually Is a sign that the rings do W 6t properly, but it Is not a sign t new rings alone will cure these 'roubles. Yon must find out the con-flitlnn con-flitlnn of ,he cylinders Into which the nil?s fit. This means the grooves i'ist he trued In a lathe to the exact !;ze of the new ring. |