INSTALLATION OF AN OIL ENGINE General.—The average engineer takes up the problem of installing an oil engine with a feeling of foreboding and dread. This is due to his inexperience in this character of work. It is not an impossible task; indeed, it can hardly be termed difficult if the matter is approached with composure. Under ordinary conditions the engine builder insists on supplying an erector as a safeguard that his interests are protected. Certain details, such as excavation, foundation work, etc., are delegated to the purchaser. Even in the actual work of assembly many factory engineers place the responsibility of setting the frame on the foundation onto the plant engineer. If the latter is capable, he will speedily find that he must direct the erection of the entire engine with the exception of a few important parts. Since there are many second-hand oil engines offered for sale, it behooves the engineer to place himself in possession of sufficient knowledge to enable him to erect any of these that might be. purchased.
Excavation.—The first problem that presents itself is the matter of foundation excavation. With small belted • units the easiest and the best procedure is to make the foundation pit rectangular, of the size shown on the manufacturer's setting plan. Use can then be made of the earth sides of the pit as the form walls. If the foundation is desired with sloping sides, the earth can be undercut, and, unless it be sandy, the sides will not crumble to any great extent.
With engines above 200 h.p. the expense of a wooden form is low enough to justify its use since it will simplify the work of excavation. In making the excavation it is a good policy to remove enough earth around the foundation proper to accommodate a pipe trench or chase. The use of a chase enables the erector to place all the water and oil piping out of sight yet accessible. This method of pipe disposal is far superior to that, followed by many erectors, of installing the pipe in the floor, permanently covering it with concrete.
After removing the earth, wooden forms are next installed, outlining the shape of the engine foundation. A form often employed is made up of 1-inch rough lumber nailed to 2X4 in. studding. Frequently the manufacturer's draftsman indulges his fancy in giving the foundation a multitude of steps and angles.
It is advisable to boldly depart from all unnecessary shapes and make the foundation as nearly rectangular as possible. Some designers claim that the earth pressure on the foundation steps eliminates the vibration that is common to many engines. The total earth pressure is so slight that the results secured are in significant. The proper method of preventing vibration is the use of generous dimensions in the footing and in the foundation proper. Frequently the eradication of the many irregular shapes entails the employment of more concrete than otherwise, but it will prove cheaper in the end. Concrete is lower in cost than the carpenter work of making forms.
In locations where "made ground" is encountered it becomes absolutely necessary to provide piling under the foundation. A very common practice is to drive two rows of piles 10 to 20 feet long, the piles being some 8 feet apart. A 3-foot diameter excavation is made about each pile-head 2 or 3 feet deep. These round holes are filled with concrete as the foundation is poured. Such a plan provides a secure footing that will prevent any displacement of the foundation.
Establishing Engine Center Line.—Before pouring the con crete, it is necessary to set the template. In the majority of installations it is usual to have the engine align with some shaft already installed. The proper way to establish the engine shaft center line is by the use of an engineer's transit. This is set under the existing shaft and sighted along the shaft. Dropping two plumb lines from the shaft makes the locating of the line an easy problem. After the line of sight is established, and the datum mark made, the transit is turned 90 degrees and a stake set along the desired engine shaft line. Moving the transit to this latter stake, it is sighted on the datum stake or mark. This establishes a line of sight at right angles to the line shaft. Turning the tran sit 90 degrees and driving a stake along the new line of sight gives two points in a line parallel to the datum shaft. After these two points are located, a strong piano wire run through them will indicate the desired engine shaft center line. The anchorage for the wire ends should be substantial since workmen in moving material quite often strike it.