Legends of power units developed in the Soviet Union include the ZMZ-402 model. The official manufacturer of the power plant is the Zavolzhsky Engine Plant. The plant produced several series, including the 24-D version, which did not take root in serial consumption due to expensive maintenance and frequent breakdowns. consider the features and characteristics of the device.
Development and creation history
The chief designer of the ZMZ-402 motor was engineer G.V. Evart. The motor in question was supposed to replace the "Volga" analog of the GAZ-21 type. The specified power unit is often called the offspring of model 21. Initially, it was planned to install the engine on various car models.
The ZMZ-402 motor has improved characteristics in terms of a cooling system, which reduces fuel consumption. This version was withdrawn from mass production due to overheating of the motors, sometimes leading to catastrophic situations.
Application
The use of the ZMZ-402 motor is predisposed to be installed on a number of passenger vehicles. This power unit can often be found on the "UAZ" model 469. This is due to the fact that outdated engines were going through hard times.
It was during this period that it was decided to replace the “engines” with analogues from ZMZ. This practice did not take place for long. Soon, Ulyanovsk competitors presented a full-fledged version, an order of magnitude improved.
Refinement and installation
Upgrading the ZMZ-402 unit will not be a particular problem. When upgrading, many users try to change the carburetor injection system to an injection analogue. First of all, the piston block is subjected to refinement. For example, instead of the standard item, a light version is mounted. This makes it possible to increase the torque and increase the power indicators of the power unit.
At the next stage, the crankshaft is grooved and the inserts of the sports sample are installed. As a result, the dynamics and speed increase increase. Carry out manipulations with the block of supply and exhaust gas. To do this, change the regular collectors to advanced modifications, and also put a carburetor from the VAZ-2107 or an analogue with a single injector. The benefit here is to reduce fuel consumption. To improve the flow of the air mixture will additionally allow an atmospheric filter of zero resistance.
Modify the ignition ZMZ-402. Between the contact and non-contact type of start, an intermediate option is often chosen with a start from the button, without using a key. As part of the modernization of the specified power unit, such a system has become quite popular.
Maintenance
One of the points of service, according to the technical cards of the manufacturer, is regular maintenance, which includes:
- Oil change with filter after 1 thousand km.
- A similar procedure with the replacement of an air element, spark plugs, wiring after 8 thousand kilometers.
- Repeated works indicated above are carried out after 17,000 km.
- Additionally, after 25 thousand kilometers, the valves are adjusted and the procedure characteristic of the eight-thousand-mile run.
- After 35,000 km, timing with a belt is changed.
Diagnostics
In this mode, the hardness and thickness of the necks of the crankshaft and the subsequent maintainability of the assembly are determined. A similar procedure is applied to the ZMZ-402 cylinder block; sleeves are measured to calculate the possible volume of piston repair. If possible, the details are ground and grinded, or replaced with new elements.
On the diagnostic operation, cracks in the body are detected. To do this, close all openings except the inlet socket for supplying refrigerant. Kerosene or hot water is fed into it, which will show the presence of deformations. If they are, the unit must be welded. An argon technique is used, since the block is made of aluminum. In some cases, cold welding may be used.
Main problems and repairs
The ZMZ-402 engine is easily repairable, even if it is in the worst possible technical condition. The list of works includes the engine bulkhead with the cylinder head and the replacement of consumables. The process is carried out in stages, starting with a diagnosis. Also, a number of works are included in the overhaul of the power unit, which we will consider further.
The motor is completely disassembled, the head is dismantled, the pallet and other parts are removed. In the process, the unit is simultaneously defective (washing the cylinder block, pressing, measuring the crankshaft).
BC and crankshaft are bored. If the parts have worked out their useful life, standard 92 mm sleeves are mounted. At this stage, honing is performed (boring the cylinder block using a special machine that polishes the elements using a special stone at high speeds).
Cylinder head ZMZ-402
This assembly is also subject to overhaul. The list of works mainly includes the following operations:
- Valve replacement.
- Installing new oil seals, cuffs, seats and valves.
- Installation of new guide bushings.
- Using k-line technology with 9 mm sleeves.
Quite often, the camshaft is replaced. The wear of the element reaches its maximum performance after 20 years of operation, therefore special attention is paid to this spare part, if necessary, the block head is ground.
Characteristics in numbers
Below are the main parameters of the ZMZ-402 motor (carburetor):
- Type - gasoline engine.
- Configuration - internal combustion engine with four longitudinally placed cylinders.
- Modifications - 402, 4021, 4025, 24C.
- Power - 95 horsepower.
- Bore / Stroke - 92/92 mm.
- The number of valves is 8 pieces.
- Type of cooling - liquid type.
- The material of manufacture is aluminum alloy.
- Ignition assembly - contact or non-contact system.
Features
The main bearing caps are made of cast iron by forging, each element is fixed on the block by a pair of studs (12 mm in diameter). The first hatch is equipped with slots for mounting the thrust bearing washers. The assembly assembly with the block is bored; during repair, they must be installed in their place. To facilitate this process, all covers are marked with serial numbers.
An aluminum cover of timing gears with a paronite gasket and a rubber sealing sleeve is attached from the end. At the rear there is a clutch housing secured by six bolts. The exact location of the element, which allows the gearbox to function correctly, is provided by a pair of mounting pins (13 millimeters).
The ratio of the axles of the input shaft of the gearbox and the crankshaft is guaranteed by the rear end of the crankcase with a special mounting hole. Due to the design features, these parts are not interchangeable. The cylinders of the unit are made of easily removable wet sleeves, cast from wear-resistant cast iron, the base is placed with the lower part in the provided socket.
Recommendations
ZMZ-402 valves should fit in place when assembling the motor. With the right actions, the volume of the combustion chamber will be up to 77 cubic centimeters. The difference between the capacity of the compartments of the engines in question, depending on the modification, should not exceed 2 cubic meters. see. Every 20 thousand kilometers of the track, it is recommended to tighten the cylinder head mounting and adjust the gaps between the valves and rocker arms.
When performing the specified process on a hot motor, the tightening of the nuts after cooling the unit will not be complete. This is due to a significant difference between the expansion coefficients of the studs, block and head of the device. In this regard, the fixation of all fasteners is performed on a cold engine. Housing models on domestic machines do not require special maintenance, except for the timely addition of oil, cleaning from dirt, dust and tightening the connections on the thread.
Exploitation
The GAZ ZMZ-402 domestic motor was installed not only on the cars of the Gorky plant, but also on similar vehicles. In many ways, this situation has developed with the transition period from the obsolete UMP-417 to 421.
The specified modification of the internal combustion engine was also actively used at the Gazelles in various designs. Later, these engines on small trucks were replaced by versions under the indices 405 and 407. The ZMZ-402 engine was quite widely used not only in the USSR and the post-Soviet space, but also in the Baltic states, Germany, and Africa.
Modernization
The easiest way to “pump” the Volga or another machine with the ZMZ-402 installation is to use a compressor of the SC-14 type, followed by blowing the carburetor. ShPG at the same time does not need strengthening. The system withstands pressure without problems of the order of 0.5-0.7 bar, the exhaust part is changed to a direct-flow element.
Such a performance is not distinguished by elegance and beauty, but it gives a good effect, in terms of dynamics and economy. In addition, it is recommended to install and adjust the forged crankshaft, special receivers, and the injector drive. In terms of turbocharging, it is advisable to choose a suitable manifold, nozzles, pipings and shafts. As a result, the cost of modernization in this way will cost double or even triple the price. Therefore, such modernization is rarely practiced at ZMZ-402. Usually they strengthen the atmospheric part of the unit or rearrange some parts from an analog of the ZMZ-406 type.
To summarize
As you can see, the engine in question was very popular for installation on many domestic and some foreign models of cars. The advantages of the "engine" include its reliability and high maintainability. With proper maintenance, the power plant is able to work up to 500 thousand kilometers without major repairs.