ZMZ-402: device specifications

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

The ZMZ-402 model rightfully belongs to the legends of power units developed in the Soviet Union. The official manufacturer of the power plant is the Zavolzhsky Motor 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 history of creation

The chief designer of the ZMZ-402 motor was engineer G. V. Evart. The motor in question was supposed to replace the "Volga" analogue 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 engine has improved performance in terms of the 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 This version was withdrawn from mass production due to overheating of the motors, sometimes leading to catastrophic situations.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 installation 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 This is due to the fact that outdated enginesgoing through hard times.

It was during this period that it was decided to replace the "engines" with analogues from ZMZ. This practice did not last long. Soon, Ulyanovsk competitors presented a full-fledged version, improved by an order of magnitude.

Revision and installation

Upgrading the ZMZ-402 unit will not be any particular problem. Many users are trying, with improvement, to change the carburetor injection system to an injection analogue. First of all, the piston block is subjected to refinement. For example, instead of a regular element, a lightweight version is mounted. This makes it possible to increase torque and increase the power output of the power unit.

At the next stage, the crankshaft is turned and the inserts of the sports sample are installed. As a result, dynamics and speed increase increase. Manipulations are carried out with the block for supplying and discharging exhaust gases. To do this, they change the standard manifolds for improved modifications, and also put a carburetor from the VAZ-2107 or an analogue with a mono-injector. Here the benefit lies in reduced fuel consumption. An atmospheric filter of zero resistance will additionally improve the supply of the air mixture.

The ZMZ-402 ignition is being finalized. Between the contact and non-contact type of start, an intermediate option is often chosen with a start from a 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 momentsservice, according to the technical cards of the manufacturer, is regular maintenance, which includes:

• Oil oil change with filter after 1 thousand km.
• Same procedure with replacement of air element, spark plugs, wiring after 8 thousand kilometers.
• Repeat the above work after 17,000 km.
• Additionally, after 25 thousand kilometers, the valves are adjusted and the procedure is typical for the eight thousandth run.
• After 35,000 km, change the timing with a belt.

Diagnosis

In this mode, the hardness and thickness of the crankshaft journals and the subsequent maintainability of the assembly are determined. A similar procedure is applied to the ZMZ-402 cylinder block, the sleeves are measured with the calculation of the possible volume of piston repair. If possible, parts are ground and machined, or replaced with new elements.

During the diagnostic operation, cracks in the hull are revealed. To do this, close all openings except for the refrigerant inlet. Kerosene or hot water is supplied to it, which will show the presence of deformations. If they are, the unit is subject to welding. Argon technology is used, as the block is made of aluminum. In some cases, cold welding may be used.

Major problems and repairs

The ZMZ-402 engine is quite easy to repair, even if it is in the worst possible technical condition. The list of works includes a bulkhead of the motor with the head of the blockcylinders and replacement of consumables. The process is carried out in stages, starting with diagnostics. Also, the overhaul of the power unit includes a number of other works, which we will consider further.

The motor is completely disassembled, the head is dismantled, the pan and other parts are removed. In the process, the unit is simultaneously debugged (washing the cylinder block, pressing, measuring the crankshaft).

BC and crankshaft are bored. If the parts have worked out their resource, standard 92 mm sleeves are mounted. At this stage, honing is performed (boring the cylinder block using a special machine that polishes the elements with a special stone at high speeds).

Cylinder head ZMZ-402

This node is also subject to reassembly. The list of works includes mainly the following operations:

• Valve replacement.
• Installation of new oil seals, cuffs, seats and valves.
• Installation of new guide bushings.
• Using k-line technology with 9mm cases.

Quite often the camshaft is replaced. The wear of the element reaches its maximum after 20 years of operation, therefore, special attention is paid to this spare part, if necessary, the block head is ground.

Specifications in numbers

The following 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, 24S.
• Power - 95 horsepower.
• Diameter/stroke - 92/92 mm.
• Number of valves - 8 pieces.
• Type of cooling - liquid type.
• Production material - aluminum alloy.
• Ignition unit - contact or non-contact system.

Features

The main bearing caps are made from forged cast iron, each element is fixed to the block with a pair of studs (12mm diameter). The first hatch is equipped with sockets for mounting thrust bearing washers. The assembly with the block is bored; during repairs, they must be installed in their places. To facilitate this process, all covers are marked with serial numbers.

An aluminum timing gear cover with a paronite gasket and a rubber seal is attached to the end. At the rear there is a clutch housing, fixed with six bolts. The exact location of the element, allowing the correct functioning of the gearbox, is ensured by a pair of dowel pins (13 millimeters).

The ratio of the axes of the input shaft of the gearbox and the crankshaft guarantees the rear end of the crankcase with a special mounting hole. Due to 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 at the bottom in the provided seat.

Recommendations

ZMZ-402 valves should be placed in their place whenmotor assembly. 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 under consideration, depending on the modification, should not exceed 2 cubic meters. see. Every 20 thousand kilometers, it is recommended to tighten the cylinder head mount and adjust the clearances between the valves and rocker arms.

When performing the above process on a hot engine, the tightening of the nuts after the unit cools down will not be complete. This is due to the significant difference between the expansion coefficients of the studs, the block and the fixture heads. In this regard, the fixation of all fasteners is performed on a cold engine. Case models on domestic machines do not require special maintenance, except for the timely addition of oil, cleaning from dirt, dust and tightening threaded connections.

Operation

The domestic engine GAZ ZMZ-402 was installed not only on cars of the Gorky plant, but also on similar vehicles. In many ways, this situation has developed with the transition period from the outdated version of UMZ-417 to 421.

The indicated modification of the internal combustion engine was also actively used on Gazelles in various versions. Later, these engines on light trucks were replaced by versions under the indices 405 and 407. The ZMZ-402 engine was quite widespread not only in the USSR and the post-Soviet space, but also in the B altic States, Germany, and Africa.

Modernization

The easiest way to "pump" the "Volga" or another car withThe ZMZ-402 installation is the use of an SC-14 type compressor, followed by blowing the carburetor. At the same time, the SPG does not need to be strengthened. The system can withstand a pressure of about 0.5-0.7 bar without problems, the exhaust part is changed to a straight-through element.

This performance is not distinguished by elegance and beauty, but it gives a good effect in terms of dynamics and economy. Additionally, it is recommended to install and adjust a forged crankshaft, special receivers, and an injection drive. In terms of turbocharging, it is desirable to choose a suitable manifold, nozzles, pipings and shafts. As a result, the cost of upgrading in this way will cost double or even triple the price. Therefore, on the ZMZ-402, such modernization is rarely practiced. Usually they reinforce the atmospheric part of the unit or rearrange some parts from an analogue of the ZMZ-406 type.

Summarize

As you can see, the engine in question was very popular for installation on many domestic and some foreign car models. 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.