Pistons and cylinders
For light metal cast pistons (8 valve engine) or for forged flat bottom pistons (16V) there is a steel liner that reduces thermal expansion. In the upper third of each piston, three piston rings are elastically inserted into the corresponding grooves in the piston. They are pressed, springy, against the wall of the cylinder. The two upper piston rings close the path of the air-fuel mixture from the combustion chamber down to the crankcase, while the lower oil scraper ring prevents too much lubricant from the crankcase from entering the combustion chamber. There is a recess at the base of the piston. It leaves the valves sufficient freedom of movement.
The photo shows the engine type designation stamped on the left rear of the engine block, followed by the 1.8L 16V engine number.
This drawing of an 8-valve engine with a displacement of 1.6 liters shows the following structural components:
1 - drive pulley of a polypin belt;
2 - inductive pulse sensor;
3 - pulley of the polypin belt of the servo pump;
4 - tension roller of the polypin belt;
5 - generator;
6 - front cover of the toothed belt;
7 - Multec central injection system;
8 - ignition module DIS;
9 - lambda probe;
10 - oil filter;
11 - flywheel;
12 - crankcase.
The cylinders, in which the pistons move up and down, are built into the material of the gray cast iron cylinder block. Cylinder bores are honed (polished) so-called mesh grinding. The walls must not be absolutely smooth, otherwise the oil needed for lubrication will not be able to adhere to them. The cylinder bores are 0.02 mm - 0.04 mm wider than their corresponding pistons. When the engine is overhauled, the cylinder guides - depending on the degree of wear - can be bored out by several hundredths of a millimeter. There is a corresponding piston for each grinding size.
The function of the crankshaft is to convert the linear motion of the pistons sliding up and down in the cylinders into rotational motion. To connect the pistons to the crankshaft, connecting rods are used, which can be rotated at both ends.
Crankshaft
Separate crankshaft crankshafts are displaced relative to each other by 180 s, while the cranks of the 1st and 4th cylinders, as well as the 2nd and 3rd ones, are oriented in the same way. To reduce vibration during operation, counterweights are installed on the opposite side of the connecting rod journal of the crankshaft to compensate for imbalance.
To prevent deflection of the crankshaft during operation, it has five bearings in the cylinder block. Each crank, on which the connecting rod is located, respectively, rests on the main bearing on both sides.
The main journals of the crankshaft and their connecting rods can be bored, both in diameter and in width. For modified dimensions, corresponding bearing shells are available as spare parts.
At the rear end of the crankshaft is a disk with a ring gear for the starter gear.
The crank mechanism, including pistons, includes the following parts:
1 - pistons;
2 - piston pins;
3 - piston rings;
4 - connecting rods;
5 - bearing shell;
6 - flywheel with a ring gear for a starter;
7 - crankshaft;
8 - bearing bracket;
9 - bearing bracket bolt.
8-valve engine with a displacement of 1.6 liters in cross section:
1 - connecting rod;
2 - piston;
3 - cylinder head cover;
4 - camshaft;
5 - hydraulic pushers;
6 - exhaust manifold;
7 - toothed disk for an inductive pulse sensor;
8 - oil receiving snorkel.
This is either the flywheel, on which the clutch is mounted and thereby provides communication with the gearbox, or the drive pulley, to which the automatic transmission torque converter is screwed. On the front end of the crankshaft are screwed: toothed belt drive pulley, impulse sensor pulley and V-ribbed belt pulley. In addition, an oil pump is still located at the front end of the crankshaft.
Connecting rods
Four connecting rods, each with two bearing shell halves, are mounted on their crankshaft crankpins. The connecting rod and piston are provided by a piston pin. It is inserted into the hole of the heated connecting rod and at the same time into the finger eye in the piston. Thanks to this, it sits firmly in the connecting rod and rotates in the piston.
Visitor comments