In a general sense, the most impressive feature of the Locomobile motor is its strength of construction. The design is substantial, the quality of material is the best, the workmanship is accurate, and the system of testing is elaborate and thorough. These precautions combine to make a motor that will keep running satisfactorily year after year.

Crank-Case.

One of the most interesting details of the Locomobile motor is the substantial bronze base on which the cylinders rest. Bronze makes an absolutely rigid structure, which greatly prolongs the life of the motor. Aluminum, which is commonly used for the purpose, has but one-third the strength. In a bronze base, such as is used on the Locomobile, there is no danger of fracture or of the bearings getting out of line. The bottom portion of the engine consists of an aluminum casting bolted underneath the bronze engine base and used to contain the oil for the lubrication of the motor. Inasmuch as this part of the engine is not subjected to stress, aluminum is used to save weight.

Crank-Shaft.

This very important part of the motor is notable for its strength and fine workmanship. The crank-shaft of the Locomobile is a solid bar of alloy steel, which is first pressed out in rough form on a hydraulic forge and then heat-treated. The crank-shaft is machine finished all over, from end to end, whereas in most crank-shafts the bearings only are machined. It is balanced on a testing device with knife blades prepared for the purpose. The crank-shaft is forged with a flange at the rear end to which the fly-wheel is substantially secured. The crank-shaft rests on main bearings of liberal dimensions, perfect alignment being established before the crank-shaft is assembled in its bearings. The bearings of the motor consist of the alloy steel surface of the crank-shaft rotating in bushings of white bronze, compressed to the proper density and highly polished by a special process of our own. The bearing caps are secured by four double lock nuts and cotter pins.

Cam-Shafts.

Locomobile forgings with cams integral. Cam-shafts are heat-treated to secure proper hardness and are ground all over. Cams are ground on a special machine with special fixtures and are absolutely accurate.

Connecting Rods.

Locomobile connecting rods are very strong, drop forged from special steel in our shops. The bearings of the connecting rod on the crank-shaft are similar in construction to the main bearings, and are made adjustable by thin copper shims. The connections are very strong, the bearing caps being secured to the connecting rods by four studs a nut, lock nut, and cotter pin for each stud.

Pistons.

Selected gray iron castings are used, each casting being subjected to a sand blast and a careful hand filing. This shows up defective material, also removes any partially loose metal and prevents it from working into the motor and cutting the bearings. The pistons are carefully turned on a lathe, and then ground to exact size, the finished piston having a slight taper at the top to allow for expansion caused by the greater heat of the piston at its upper end. Piston rings are four in number, cut from specially selected, springy stock. The rings are turned eccentric, cut at an angle of 45 degrees, then compressed to circular form, held in a fixture, and ground all over their entire circumference. Pistons with rings in place are lapped with an abrasive compound until they fit perfectly.

Wrist Pins.

Pistons are secured to the connecting rods by hardened steel wrist pins ground to size. The wrist pins are forced into the pistons with a very close fit preventing any up-and-down motion, and are secured to the pistons by steel studs, which keep them from turning or moving laterally. The studs are prevented from working loose by a steel wire, the ends of which pass through holes drilled in the ends of the studs, and are then bent around. The wrist pin bearing is a steel bushing, hardened and forced into the small end of the connecting rod. Special provision for thorough lubrication of all wrist pins is provided.

Vahe System.

The valve springs are of specially selected stock, the valves are carefully made and precisely set the entire system may be operated for long periods of time without need of attention. Cam rollers are hardened steel and have a long bearing in the bronze lifter guides, a form of construction which prevents wear and rattle. In case it is desired to check the timing of the valves, marks on the fly-wheel enable this to be done with promptness and certainty.

Pump.

The centrifugal water pump is located on the exhaust side of the motor. The pump shaft is driven by a gear meshing with the exhaust cam-shaft gear.

Cylinders.

Locomobile cylinders are cast in pairs with valve boxes and water jackets integral. The practice of casting cylinders in pairs is considered to be the best as it produces a compact motor and does not limit the size or arrangement of motor bearings. A bronze cover plate is used for each pair of cylinders and carries the fittings for the water connections and the pet cocks. This form of construction greatly facilitates the production of perfect cylinder castings, enables the water jackets to be made uniform, and thoroughly cleaned out before the motor is built. This insures perfect cooling circulation. All cylinder castings are subjected to a very careful inspection, to a sand blast, hand filing, and finally to a cold water test. The cylinders are bored three times, and ground to exact size with water flowing through the water jackets to keep the temperature uniform and prevent distortion. Each pair of cylinders is secured to the bronze crank-case by eight strong heavy studs, with double lock nuts and cotter pins. This absolutely prevents the cylinders from coming loose. The compression is about 65 to 70 pounds gauge pressure, and the compression spaces are calibrated so that the compression is uniform in all cylinders.

Timing Gears.

Placed at the front of the motor in a housing formed by an extension of the bronze engine bed, protected by an aluminum cover. The timing gears are of metal and cut in our shop, following our practice for the past eight years or more. Metal gears are unaffected by the action of oil; fibre gears or composition gears swell when immersed in oil and shrink when the car is not used; and do not wear as long as metal gears. There are five gears in the case: crank -shaft gear, admission cam-shaft gear, exhaust cam-shaft gear, pump gear, and magneto gear. The separate gears are cut, and the complete train of gears assembled, with the greatest possible care to produce silent running. Lubrication is continuous and thorough.

Testing.

We have tested under its own power every motor that we have ever built, and we have preserved a record of this test. This will indicate our endeavor to make every motor as perfect as possible. When the motor is completed it is flooded with oil

Building the Locomobile Motor.

Tenth View Complete with magneto, wiring and spark plugs and placed on a stand where it is driven by a belt for a considerable period. It is then placed on the test stand, and equipped with its own carbureter and magneto and ignition apparatus, and run under its own power, slowly at first. After it is broken in, its power is tested by engaging the fly-wheel with the armature shaft of a dynamo. As the motor drives the dynamo its mechanical power is transformed into electrical power, which is easily and exactly measured. Each motor is operated on the test stand until it fulfills the established requirements.

Oiling System “40″.

Oil contained in the pan under the motor is splashed about, lubricating pistons, cylinders, and wrist pins. A gear-driven oiler forces oil through leads in the crank-shaft, thence through all its bearings.

Oiling System “48″.

A gear-driven pump forces oil to the bearings in a constant stream. Connecting rods dip into troughs the height of which is such that complete lubrication is assured; this feature in combination with baffle plates prevents any excess of oil and consequent smoking at the exhaust. A strainer prevents any clogging of the circulating system and can be removed for cleaning. An oil by-pass combines the advantages of a gravity head with a circulating system and does away with any tank under the bonnet.