methods of fastening manifolds on the cylinder casting, the most common being by retaining stirrups as shown in engine at Fig. 88, or by flanges and bolts as outlined in illustrations of engines at Fig. 89. As will be evident, where cylinders are of the T-head form with valves on opposite sides of the cylinder casting, the bolt and flange system is generally used. On L-head motors, where the valves are in the same extension of the cylinder casting, the bolt and stirrup retention method is generally followed. One may safely say that engines of low and moderate priced cars, being of the L-head form will have the manifold retained by stirrups and bolts, whereas the T-head power plant of the larger and higher priced cars will use the bolted manifold construction. It is now common practice to cast all cylinders together, blocks of four being very common and blocks of six are not rare enough to cause comment. In some cases the manifolds are cored integral with the cylinder casting and it is merely necessary to remove a short pipe leading from the carburetor to one inlet opening and the exhaust pipe from the outlet opening common to all cylinders. In order to remove the carburetor it is necessary to shut off the gasoline supply at the tank and to remove the pipe coupling at the float chamber. It is also necessary to disconnect the throttle operating rod. After the cylinders are removed and before taking the crankcase apart it is well to remove the water pump, magneto, and mechanical oiler if that system of lubrication is used. The wiring on most engines of modern development is carried in conduits and usually releasing two or three minor fastenings will permit one to take off the plug wiring as a unit. The wire should be disconnected from both spark plugs and magneto distributor before its removal. The appearance of the engine shown at the bottom of Fig. 89, after the magneto ignition wiring, spark plugs and front of timing gear case are removed is shown at Fig. 91, A. The next operation in dismantling this engine is to take off the four nuts holding the induction manifold to the cylinder castings and when the manifold is removed the carburetor comes with it. The appearance of the engine after this has been done is shown at Fig. 91, B. The next parts to be taken off, the cylinder castings, are shown shaded in this view. The appearance of this engine after the cylinders have been removed is clearly indicated at Fig. 92. In this case the magneto or water pump has not been disturbed. The pistons, piston rings, and connecting rods are clearly exposed and their condition may be readily noticed. Before disturbing the arrangement of the timing gears, it is important that these be marked so that they will be replaced in exactly the same relation as intended by the engine designer. If the gears are properly marked the valve timing and magneto setting will be undisturbed when the parts are replaced after overhanling. When an engine has been taken down to the point shown at Fig. 92, it is possible to ascertain if there is any undue wear present in the connecting rod bearings at either the wrist pin or crank pin ends and also to form some idea of the amount of carbon deposits on the piston top and back of the piston rings. Any wear of the timing gears can also be determined. The removal of the bottom plate of the engine enables the repairman to see if the main bearings are worn unduly. Often bearings may be taken up sufficiently to eliminate all looseness. In other cases they may be worn enough so that careful refitting will be necessary. All engines are not of the type shown at Figs. 88 and 89. Where the crankcase is divided horizontally into two portions, the upper one serving as an engine base to which the cylinders and in fact all important working parts are attached, the lower portion, performs the functions of an oil container and cover for the internal mechanism. There is a tendency on the part of modern designers to combine the cylinders and a portion of the crankcase in one casting, using a detachable cylinder head construction in order to permit valve grinding and carbon removal without taking the engine out of the chassis frame. The connecting rods and pistons may also be removed where this construction is followed through the opening left after the detachable cylinder head is removed. In the engine shown at Fig. 93, not only the cylinders but practically the entire engine crankcase, except for the plate closing the bottom is cast in one unit. It will be evident that the removal of the bottom plate and cylinder head will provide access to the interior of the motor. Attention is directed to the inlet manifold construction which is cored in the cylinder block. The exhaust |