Contents: Engine cylinder block ↡ Cylinder head ↡ Cylinder liners ↡ Pistons ↡ Connecting rods ↡ Crankshaft ↡ Valves ↡ Camshaft ↡ Flywheel ↡
Diesel engines with a capacity of 2.3 and 2.9 liters, designated as 601 and 602, were previously installed on other Mercedes-Benz vehicles, with the only difference being that the 602 engine is now equipped with a direct injection system.
Engine cylinder block
Most of the main units necessary for the engine to operate, such as the generator, starter, and fuel pump, are attached to the cylinder block. The lower part of the cylinder block forms the engine crankcase. Both engine types are equipped with replaceable cylinder liners, which can be replaced if the degree of cylinder wear exceeds the maximum permissible limit.
Cylinder head
The cylinder head is attached directly to the cylinder block. The head contains channels for air supply and exhaust gas removal, valve seats, bearings and guides for the valve timing mechanism parts, channels for coolant circulation, pre-chambers and the combustion chamber itself. The cylinder head gasket, placed between the cylinder head and cylinder block surfaces, prevents air and coolant from entering the cylinders. The camshaft is also installed in the cylinder head.
Cylinder liners
The cylinder liners together with the cylinder head form the fuel combustion zones. The inner surface of the cylinder liners has a honed surface and is precisely matched to the piston diameter. For cooling, a liquid is used that washes the outer walls of the sleeves, flowing through channels made in it.
Pistons
The pistons perceive the pressure of the burning fuel and transmit it through the connecting rods to the engine crankshaft. These types of engines use special pistons with a star-shaped combustion chamber. The main components of a piston are the piston crown, the ring area containing the piston rings, the skirt and the piston pin bosses. The piston pins are secured with retaining rings in the piston bosses. Two upper piston rings (sealing rings) prevent the breakthrough of gases from the fuel combustion zone into the engine crankcase. Bottom (oil scraper ring) removes excess oil from the cylinder walls and dumps it into the engine crankcase.
Connecting rods
Connecting rods connect the pistons to the engine crankshaft. The main components of the connecting rod are the connecting rod upper head (covers the piston pin), connecting rod, lower connecting rod head with cover (covers the crankshaft journal)
Crankshaft
The crankshaft converts the reciprocating motion of the pistons into rotary motion. Its main parts are the root necks (for installation in plain bearings of the crankcase), connecting rod journals, shaft cheeks (connect the main journals to the connecting rod journals). On all engines, the crankshaft is mounted on several plain bearings with replaceable liners. The number of main bearing supports on engines 601 and 602 is not the same.
Valves
With the help of valves, fresh air is admitted and exhaust gases are released. All parts involved in opening and closing the valves are called the valve timing mechanism. All engines considered in this publication have 8 valves (four-cylinder) and 10 valves each (five-cylinder).
Camshaft
The camshaft opens and closes the valves in accordance with the working process occurring in the engine cylinders. Each valve is controlled by a hydraulic tappet, equipped with a valve clearance compensator and driven by a camshaft cam. The camshaft, in turn, is driven by the crankshaft via a chain drive. Four-cylinder engines are equipped with 5-bearing camshafts, and six-cylinder engines with 6-bearing camshafts, which have the same diameter - 31 mm. The lower part of the camshaft bearings is made directly in the body of the cylinder head housing. The camshaft is held from axial movements by a thrust ring, which is secured to the cylinder head in a special groove in the end part of the cylinder head. On the flange of the camshaft there is a mark marking the position of the TDC of the piston of the first cylinder. Next to this mark is the camshaft identification number. Using this number and the spare parts specification, you can select the required camshaft.
Flywheel
The engines in question are equipped with special sectional (dual mass) flywheels. The purpose of such a flywheel device is to smooth out the torque fluctuations that inevitably arise on the crankshaft due to the operating characteristics of an internal combustion engine, and to prevent further transmission of these fluctuations to the transmission. The use of a flywheel reduces the noise level generated by torsional vibrations. The flywheel design is as follows: the front flywheel disk is rigidly fixed to the crankshaft. A torsional vibration damper is mounted on this disk, which is a structure consisting of springs and balancers. The rear part of the flywheel is attached to the torsional vibration damper and has no rigid connection with the front flywheel disc. Thus, the clutch, mounted on the rear flywheel disc, is connected to the engine through a damper.