Applying the information in this chapter
Chapter 25 describes repair procedures that are performed on the engine installed in the vehicle and contains only the specifications that correspond to these procedures. Since these procedures are performed on the engine installed in the vehicle, some of the preceding removal operations must be skipped when the engine is removed from the vehicle and mounted on a stand.
Information pertaining to engine/transmission removal and installation and engine repair can be found in Chapter 2B. It also contains specifications pertaining to these procedures.
General description of the engine
The engine, also known as the Duratec (used internally by Ford), is a 6-cylinder, V-shaped engine mounted transversely at the front of the vehicle. The transmission is located on the left end of the engine. The main engine castings are made of aluminum alloy, including the cylinder heads. Each cylinder has 4 valves - two inlet and two outlet. The total number of engine valves is 24. The intake manifold is equipped with a variable intake manifold system, switched by means of vacuum. It optimizes torque and engine power: at speeds below 3200 rpm, the engine operates effectively as a 12-valve engine, and at higher speeds it operates as a 24-valve engine.
The crankshaft rests on 4 main bearings. The bearing closest to the flywheel/faceplate assembly contains thrust washers on both sides of the liner to absorb axial forces and provide axial play of the crankshaft. The connecting rods are mounted on liners with a horizontal split of the lower heads. The pistons are connected to the connecting rods by means of floating pins, which are fixed in the pistons by elastic rings. The pistons, made of aluminum alloy, have three rings: two compression rings and one oil scraper ring. During the manufacturing process, the cylinders and piston skirts are measured and divided into three standard sizes. This is necessary to provide the required clearance between the piston and the cylinder. Repair dimensions for subsequent regrinding are not provided.
The intake and exhaust valves are closed by coil springs. The valves are installed in guides that are pressed into the cylinder head in the same way as the insert valve seats.
The camshafts are driven in pairs by two chains: one for each cylinder head. Each of these shafts acts on the valves through self-adjusting hydraulic compensators. This eliminates the need to monitor and adjust valve clearances. The intake camshaft of the front cylinder head rests on five bearings. The remaining shafts have four bearings each, which are formed by joint boring of the cylinder head and bearing caps (fastened with bolts). Therefore, the caps are not supplied separately from the cylinder head and it is also impossible to use caps from another engine.
The cooling system pump is bolted to the left end of the cylinder block and is driven by a belt from a pulley mounted on the left end of the intake camshaft of the front cylinder head.
Lubrication is provided by a pump with an eccentrically mounted rotor, which is fixed to the right end of the crankshaft. This pump sucks oil through a mesh filter located in the sump and supplies oil through a cartridge-type upstream filter mounted outside the engine. Some engine variants have an oil cooler mounted on the oil filter support and thus the clean oil entering the engine channels is cooled by the main engine cooling system. From the filter, the oil enters the cylinder block/crankcase line and then through channels to the crankshaft main bearings and to the cylinder head.
The engines described in this book are equipped with hydraulic valve lifters, which operate under the pressure of the lubrication system and automatically compensate for the clearance between the camshaft lobe and the corresponding valve stem. Therefore, adjustment and checking of valve clearances is not required. At the same time, only high-quality oils of the specified viscosity, corresponding to technical requirements, must be used in the engine, and the oil must be changed in accordance with the maintenance schedule. If these instructions are not followed, the oil passages and hydraulic valve lifters may become clogged with dirt or deposits of burnt oil particles. As a result, the performance of the system may decrease. In the worst case, one or more valve lifters may fail, which will require expensive repairs.
When starting a cold engine, oil is supplied to all engine components, especially to the hydraulic compensators, with a slight delay. Therefore, the valve components may knock for some time (about 10 seconds), after which the knocking disappears. This is normal and should not cause concern.
If the car has been parked for several days, the valve components may knock for a little longer than usual as oil drains from the top of the engine and the bearings. In this case, to avoid damaging the engine, do not run at high speeds until all the compensators are filled with oil and begin to operate normally. When the car is stationary, maintain a high idle speed (maximum 2000-2500 rpm) for 10-15 seconds, or until the noise disappears. Do not run at speeds above 3000 until the compensators are filled with oil and the noise disappears.