Arizona republican., 1918-07-21


 rings into the combustion chamber In many cases the car owner uses an oil 1 of too thin body and when rapid car- bonization takes place, he suspects the 1 pistons, the rings and almost every thing else except the true cause of the | trouble. Every car manufacturer rec ommends a certain grade of oil to be used in his engine and his advice should be rigidly adhered to by the car owner. In case there is any question in the matter, the advice of the service sta tion should be asked. The commonly recommended lubricant is a medium body oil, but this is not universal, so the car owner should make absolutely sure of his ground in this vitally inn portant matter.
 Heavier Oil for Old Cars
 It is also true that heavier grade of oil is usually needed in summer than in | cold weather. Heat tends to reduce the body of oil, thinning out the viscosity, | just as 1t does with molasses. Very often, too, heavier oil is needed in old cars than the one which served very well when the vehicle was young. The reason for this is that the parts of the mechanism have worn, the clearances are greater and heavier bodied oil is needed to stop the gaps.
 If, however, the car owner is sure that the proper amount and the proper quality of oil is being used and still sooted plugs and general carboniZation betrays the presence of oil leakage, the piston rings and the piston itself is open to suspicion.
 In many cases failure of the piston rings to prevent the oil from leaking into the combustion chamber. is due to the fact that they are not properly fitted in the cylinders. If ring is not accurately placed in its groove, or if it sticks in it's groove instead of being sprung out against the cylinder wall of course. oil can force its way into the upper part of the cylinder. It often happens that foul oil, in which there is a considerable amount of foreign mat ter, forces it's way up into the ring grooves, thereby preventing the ring from resting properly in its groove.
 Must Really Fit Rings
 Fitting piston rings means more than merely placing the rings in their grooves. The rings must fit the grooves so that there is perhaps .00l of an inch up and down clearance, or just enough to prevent leakage and still not cause the ring to stick. The ring should be Tapped to size and ring fitting should be done by experienced hands.
 There has been a tendency in recent years when engine lubricating troubles occur, to fit some special type of pistor ring and believe that settles the mat ter. Many of the special rings have real value, but they must be accurate ly fitted, just the same as an ordinary diagonally split ring.
 Watch Cylinder Wear
 Now beyond the rings as possibl, sources of fabrication trouble. there l. the cylinder itself It frequently hap. | pens that after car has been run fol a long time one or more cylinders wears out of true. Obviously in this case the ring, which is round, does no fit tight against the cylinder wall. Tn, results is a flow of oil into the combus tion chamber. The only cure for thi. condition is to have the cylinders re | bored. There are firms specializin, in this in practically every city. Ever if only one cylinder is out of round. tn, | entire set should be rebored and a ney set of pistons installed.
 In some cases it is possible to cure { chronic case of oil pumping by drill ing the skirt of the piston with Il, inch holes, spaced at equal distance under the lowest groove. This with perhaps, the addition of a scraper rin, in the skirt will often work wonders. Finally a scored cylinder win induc oil pumping. since the trenches in tn cylinder wall allow the oil to escap past the rings. In this case the cylin der will have to be operated upon b some specialist in this work