The Zetec-SE engine block is made of aluminum-silicon alloy. Reliably made side walls and main bearing bridge make the block especially torsionally rigid. 1 - Engine Block; 2 - bearing shells; 3 - crankshaft with eight counterweights and five main bearings, 4 - main bearing bridge.
Cylinder head: in modern engines it is made of light alloys, it completes the engine block from above. The cylinder head contains the intake and exhaust channels, coolant channels, lubrication channels, valve seat rings, valve guides, valve mechanism bearing journals, as well as openings for spark plugs or injectors and combustion chambers. The cylinder head gasket between the engine block and the cylinder head does not allow oil, coolant and air to pass in and out.
Cylinders: in them the pistons oscillate between the bottom dead center (BDC) and the top dead center (TDC): the working surfaces of the cylinders in their diameter exactly correspond to the diameter of the pistons and then their surfaces are specially processed again (honed). They are either indirectly cooled by cooling channels or, in the case of wetted cylinder liners, are washed directly by the cooling liquid.
Pistons: oscillate in the cylinders and transmit the combustion pressure via the connecting rods to the crankshaft. The pistons are made of particularly light and heat-resistant light alloys. Their main elements are the piston bottom, the ring area with the piston rings, the holes for the piston pin and the trunk part of the piston. The piston pin connects the piston to the connecting rod. The upper piston rings (sealing rings) seal the combustion chamber almost gas-tight from the crank mechanism. The lower ring (oil scraper piston ring) drains excess lubricating oil from the cylinder walls into the crankcase (oil pan).
Connecting rod: connects the piston to the crankshaft. Consists of a hole in the connecting rod (guides the piston pin), the connecting rod shaft, the connecting rod base, and the connecting rod base cap (the connecting rod base and the connecting rod base cap cover the crank pin with bearing liners).
Crankshaft: converts the vibration energy (piston travel from TDC to BDC) into rotational energy (rotational motion) via the connecting rod link. Modern crankshafts consist of a forged housing that rotates in the engine block main bearing areas. Depending on the number of cylinders, two crankshaft cheeks lead to the crank pins (connecting rod bearing journals) at a precisely defined offset (angular degree). Focus crankshafts have five main bearings and four connecting rod bearings offset at an angle of 90'. Replaceable three-piece plain bearings are inserted into all bearing journals.
Valves: control the gas exchange process in four-stroke engines (intake, compression, combustion, exhaust). In OHC-Endura engines, the valves are suspended "shoulder to shoulder" under the camshaft. In DOHC-Zeteconn engines, they are suspended in a V shape at an angle of 42° under the camshafts. All moving parts in the cylinder head form the valve mechanism.
Camshaft: opens and closes the valves - depending on the engine speed and the position of the pistons - at precisely defined intervals.
The camshaft drive of Ford OHC/DOHC engines is a toothed belt. 1 - exhaust camshaft, 2 - intake camshaft; 3 - inlet valve; 4 - inlet channel; 5 - roof-shaped combustion chamber; 6 - outlet channel; 7 - exhaust valve.