Page:Motors and motor-driving (1902).djvu/129

Rh, important to count the exact number of oil holes and grease cups existing in any car, and to have this painted in the car somewhere out of sight, giving instructions to the attendant to count up as he oils round. In this way no place will be forgotten.

When any difficulty occurs with a car many drivers at once accuse the electric ignition, when it exists, and next the valves, for the default. The unfortunate valve comes in for a great deal more abuse than it deserves. The less grinding they are given the better. When the operation is necessary of course it must be done. If the car is used daily, for say eight hours, and the oiling of the cylinders has been properly adjusted and not too profuse, it will be sufficient if the valves are removed weekly, to be wiped over with an oily rag, and then cleaned with a little heavy petroleum or benzine. If it should be observed that the bearing surfaces are pitted, then grinding should be resorted to, but this will not often be the case with experienced owners.

It is a very simple matter to grind the valve by adopting the following process. To give an example, we will consider the case of one valve, since it will apply equally to the others. The valve itself must be rendered free by the removal of all springs, and a little emery of the finest description, almost like flour, should be mixed up into a paste with oil. The bearing surface of the valve must then be coated with a thin layer of this paste by means of the finger, and placed upon its seating. It will be observed that there is a slot in the valve ready to receive the screw-driver. This tool is now employed in twisting the valve right and left, at the same time pressing it down on its seat with moderate force, turning always to an angle of say forty-five degrees to and fro. Then turn the valve a little round, and continue the operation, the object being not always to grind in the same place. When this operation has been continued for the space of a minute, the valve should be removed, and the rubbing surface on the valve itself, as well as its seating, be examined to see whether the