« НазадПродовжити »
be made to operate far better by feeding an excess of oil which serves to fill the leaks around piston rings and bearings and thus hold compression. Usually from six to fifteen drops per minute is sufficient for a well-cared-for motor. Another method of lubrication that has many advantages consists of oiling the motor through the gasolene. To accomplish this, oil should be added to the gasolene in the proportion of one pint of oil to five to eight gallons of gasolene. The oil and gasolene must be thoroughly mixed and this may be accomplished either by stirring them together before placing in the tank or by pouring both together through a funnel with a strainer. Another method is to mix the oil with a small quantity-about a gallon-of the gasolene and then add this to that in the tank. The oil thus mixed is held in suspension in the gasolene in minute globules, and passes with the gasolene through the carburetor. Within the motor the gasolene is vaporized, while the oil is deposited over all parts of the interior of the motor, thus lubricating it very thoroughly. This method gives excellent results but has numerous disadvantages. If one has a private gasolene supply where the oil may be properly mixed in known proportions there is little trouble, but if you purchase oil or gasolene here, there, and everywhere—as is necessary when on cruise with a boat or on a long automobile trip-it is next to impossible to get the proper proportions every time; either too much or too little oil is sure to result under such conditions, and in addition it is considerable trouble to stop and mix the oil and gasolene every time the tank is refilled. Moreover, the oil passing
through the carburetor has a tendency to keep the carburetor oily and accumulate dirt, while oftentimes the oil becomes gummy and hard from cold weather, or from the cold generated by evaporation on the carburetor, and the latter then becomes clogged and fails to operate properly. In four-cycle engines the oil often accumulates on the valve stems and causes them to stick, or is forced into the exhaust pipe and muffler, causing clogging and soot.
The most difficult parts of a motor to lubricate successfully are the piston-pin and crank-shaft bearing of the connecting rod, and this is accomplished in various ways. A common and good method is to have a hole bored through the piston-pin and another through the connecting rod connecting with the former. The oil, fed into the cylinder, lubricates the piston and also enters the hole in the piston-pin and, after lubricating the bearing at the head of connecting rod, finds its way down to the crank shaft. This method is excellent on small to medium-sized engines and is well shown in Figs. 38, M; 43 and 44, 0; and in Fig. 74.
To lubricate the crank-shaft bearings still more •effectively a splash system is used in many motors in which a quantity of oil is kept in the bottom of the crank case and into which the connecting-rod cap and crank shaft dips at each revolution, thus splashing the oil about and lubricating the various internal parts. Practically all two-cycle motors lubricate more or less on this principle, for there is always an excess of oil accumulating in the base into which the crank dips. To more evenly distribute the oil in the base a system of oil rings
is often used by the best makers of gasolene motors and has been adopted on the majority of good motors. This method consists of rings attached to the crank shaft and to which oil is fed through the base or otherwise. The centrifugal action of the oil rings, which are slightly eccentric, serves to keep up a steady and uniform feed
of oil to the various parts of the crank and shaft bearings. This ring system is far superior to the splash method, and is illustrated in Figs. 72 and 73, which show the ring used by the Buffa
lo Motor Co. and the crank Fig. 72.-"Buffalo" Oiling shaft with rings assembled. Rings
This company was the first to introduce these oil rings and they have since been adopted by many manufacturers and are used with various modifications almost universally.
A unique and very compact as well as highly satisfactory system of oiling is used in the well-known Ferro motors. This is well shown in the sectional view illustrated (Fig. 76), and consists of an oil tank in the base of motor and cast integral with it. This is filled by means of a filler tube (6) which rises from the base. A short tube fitted with a check valve connects the crank case with the tank and from the latter another tube (5) leads upward to the sight-feed distributor at top of cylinder. From the distributor various feed pipes lead to the points requiring oil. In operation the pressure in the crank case causes enough air to pass through the check valve into the oil reservoir to force the