A New Motor for Heavy Work.
Page 27
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The Forman 50h.p. Petrol Engine.
This engine, which we illustrate by Leans of a. photograph and a line rawing(showing part of it in section nd part in elevation), has been degned to meet the demand for a highowered motor for driving railway .ucks, heavy delivery vans, electricght plants, and also for marine motor ork. The design results in a rather Lassive engine, and the construction : well calculated to stand up to heavy :rvice conditions. The roomy, caston crank-case is well provided with Lspection covers and is free of all filthAlecting pockets. The cylinders, .hich are cast in pairs, are of generous roportions, and are well jacketed: the are is inches in diameter and the [sten has a stroke of 6L, inches.
Particular attention has been given ) the lubrication system, which is an nportant item on so large an engine.
illustration, unfortunately, does at show the details of the particular lethod which has been adopted. This rnsists of leads or pipes from the lubriitor to the top part of the end and :rare bearings. Grooves are cut along to metal bearings, and the crankshaft drilled in such a manner that the oil conducted from the crankshaft bearigs, along the crank-cheeks or webs, the big-end bearings. The pistons -td gudgeon pins are lubricated from le same tank, but the elbows leading ) the bore of the cylinder are furnished ith ball valves, which prevent any oil am being blown back. The bearings iroughout are made of Winans and ohinson's phosphor bronze, and the ‘st materials only are incorporated in to construction of the engine. The ninecting rods are made from steel ampings. The crankshaft, which is very stiff form and 2+ inches in diaeter, is made from a forging of steel hich has a tensile strength of 50 tons tr square inch. The valves are, of purse, interchangeable, and the rollerppet arrangement allows them to be aced directly over the cams ; side play id excessive wear on the tappets are [us eliminated.
The governor acts in conjunction with the carburetter, by means of a piston-valve. Two forms of ignition are provided on all engines of this type ; one is the Simms-Bosch high or lowtension magneto, which is driven by gearing direct from the crankshaft ; the other is the high-tension jumpspark, with coil and accumulator. The contact breaker for this latter system is mounted on a vertical shaft which is driven by bevel gearing from one of the camshafts.
The proportions of the Forman engine will be better realised, perhaps, after a brief study of the line drawing reproduced, which is drawn to scale. The overall length of the motor is 4
feet 3 inches, the overall height is 2 feet Loi inches, and the overall width IS 2 feet 6 inches. The weight of the engine, complete with all fittings, but without a flywheel, is 34 cwt. The standard flywheel which is fitted has a diameter of 22 inches. The great weight of this engine prohibits its employment in most types of motor vehicle, but it should be a serviceable engine for the heaviest classes of motor wagons or tractors where a little extra weight is not of much importance.
The engines are made at the works of the Forman Motor Company, Limited, Coventry, and are handled in London by Brown Brothers, Limited, of Great Eastern Street, E.C.