Capital repairs. Overhaul Other ways to increase power

The GAZ 24 passenger car was developed in the mid-60s of the twentieth century, and in July 1970 it completely replaced its predecessor. Accordingly, a completely different engine was created for the new Volga. internal combustion, which was assembled at the Zavolzhsky Motor Plant.

Classic car GAZ 24

Served as a prototype of internal combustion engines (ICE) ZMZ 24D and ZMZ 2401. The new motor was fundamentally similar to the power unit of the twenty-first Volga and even outwardly similar to it. But the details of the engines were almost all different, and not interchangeable with each other in the bulk.

general description

ZMZ 24D - 8-valve four-stroke four-cylinder engine, had an overhead valve arrangement and a lower camshaft arrangement. The cylinder block and cylinder head (cylinder head) were cast from aluminum alloy AL 4. The internal combustion engine was designed to run on AI-93 gasoline fuel. The ZMZ 2401 motor had the same characteristics. Unlike ZMZ 24D, ZMZ 2401 ran on A-76 gasoline. The fuel system was equipped with a two-chamber carburetor K 126G.

Engine diagram ZMZ-24D

At one time, the use of an aluminum cylinder block (BC) and block head was an innovation and was considered advanced technology. The "twenty-fourth" engines existed without any changes until 1985, when they were replaced by a new generation of ZMZ 402 and ZMZ 4021 engines.

Zavolzhsky Motor Plant continued to produce ZMZ 24D and ZMZ 2401, but as a spare unit. New and their modifications since 1987 were completed only with new engines.

Specifications ZMZ 24D and ZMZ 2401

The engines of the "twenty-fourth" series had the following characteristics:


From 5 to 5.5 liters of engine oil were poured into the engine oil sump (according to various sources), but according to verified data, five and a half liters were required to reach the full level on the dipstick.

The ZMZ 24D and ZMZ 2401 motors had only two differences between themselves - this is the cylinder head itself and the pusher rods. The head of the ZMZ 2401 block had a larger cylinder combustion chamber due to the thickening of the metal in this area. The height of the cylinder head ZMZ 2401 is 98 mm, for ZMZ 24D this parameter is 94 mm. They distinguished the cylinder head by measuring the height with a caliper, experienced minders determined the differences by eye. The rods differed in length; in the ICE version for the 76th gasoline, they were 4 mm longer.

An example of a ZMZ 24D engine for 76th gasoline

ZMZ 402 and ZMZ 4021

In 1985, a serious modernization of the "twenty-four" began. The changes concerned the interior, body,. They also touched the engine. What is most interesting, the internal "stuffing" of the engine has not changed at all, and the volume of the engine has remained the same. Why, then, all this modernization was started?

Thanks to innovations, the internal combustion engine has become more convenient to maintain and repair. Then, albeit a little, but the engine power increased. According to the design ideas, the engine resource should have increased.

The new internal combustion engines have the numbers 10 in the designation, that is, the engines have the indices ZMZ 402.10 and ZMZ 4021.10. But for simplicity, we will not prescribe the full name.

The difference between ZMZ 402 engines and ZMZ 24

It looks like the ZMZ 402 engine

There are the following differences between the two types of engines:


Prechamber engine ZMZ 4022.10

In 1981, the Zavolzhsky Automobile Plant, in order to increase the power of the power unit, creates a new experimental engine, which turned out to be transitional between ZMZ 24 and ZMZ 402. The motor was conceived for, but it was also installed by an experimental batch on "twenty-fourths". In particular, such cars were used in taxis.

This is what the new Volga Gaz 3102 looks like

The ZMZ 4022.10 cylinder block is outwardly almost indistinguishable from the 402nd engine, but was completely different inside. All the differences were in the landing of the cylinders and in the sleeves themselves.

In contrast to the easily removable liners of motors 24 and 402, which were sealed with the block through a copper gasket, the liners in the prechamber engine block were fixed with two rubber rings. They "sat" in the seat so hard that sometimes it is impossible to remove them even with a puller. By the way, such blocks were called "chill molds".

The block head had its own special design. A small combustion chamber and one small valve were added to each cylinder. The principle was that the combustible mixture is first ignited in this chamber (prechamber). Then, due to the “explosion”, the ignition of the main mixture is enhanced, which contributes to an increase in the power of the internal combustion engine.
It should be noted that the nameplate power of this unit was declared 105 hp. on the 93rd gasoline, and the engine was really very frisky and resourceful.

It was possible to determine the pre-chamber engine on the car immediately by opening the hood. This motor was given an aluminum valve cover, which is impossible to confuse with a stamped steel cover 24 and 402.

Accordingly, ZMZ 4022.10 had its own parts that are not interchangeable with any others:

  • Combined intake and exhaust manifold;
  • Carburetor;
  • rocker axle;
  • cylinder head;
  • prechamber valves;
  • Valve lid;
  • Collector gasket.

This list does not include a cylinder block and piston group liners. The fact is that the block and sleeves have found their application in the ZMZ 402 engines.

Installed motor ZMZ 402

The ZMZ 4022 motor turned out to be not a very good idea. He was very capricious in the settings of the fuel system. Quite often, the engines refused to start, it was necessary to turn the starter for hours to revive the engine. The launch could happen unexpectedly, and no one could understand what was the matter. For this reason, after three years, they decided to abandon such motors.

In the ZMZ warehouses, chill blocks and piston groups from the ZMZ 4022.10 engine remained, and these parts were put into series. Therefore, periodically during the repair of the “four hundred and second” engine, it was found that a similar unit was installed on the motor. Outwardly, such a motor can be identified by the characteristic casting of the block, and then not immediately, only with an experienced eye.

Those ICEs that presented surprises with the launch nevertheless “revived”, the method was elementary - they took the entire cylinder head assembly from ZMZ 402 and rearranged it. True, this became possible only after the 402nd engine went into series.

Malfunctions inherent in motors of the ZMZ 24 series

The malfunction of almost any engine is increased oil consumption and the knock of the crankshaft. Another thing is that for some internal combustion engines this is a “disease”, while others quite steadfastly endure overloads and oil starvation. "Volgovsky" motors belong to the group of resistant and hardened, but there are still sores.

Characteristic features of the 24th motors, which are inherent in these models:

  • Rear main bearing oil leak;
  • Wear of the bed or bushings of the camshaft, as well as the bearings of the shafts themselves;
  • Breakage or cranking of the hex drive of the oil pump;
  • Actuation of the teeth of the textolite gear of the camshaft;
  • Wear of brass bushings of connecting rods under the piston pin.

The oil leak of the rear main bearing is familiar to almost every "volgovod".
The fact is that at the junction of the two halves of the gland packing, a gap forms over time. Omental packing under the influence of temperature "dries out" and shrinks.

In addition, loose connections are created due to the drying of two rubber seals (“boots” or “flags”). Such a disease is treated by laying a good oil-resistant sealant at the joints of the seals. Of course, the padding and "flags" must be replaced. When the operation takes place in situ (without removing the crankshaft), the top packing is not changed. And yes, it's almost impossible to get there.

Replacing the rear main oil seal is useless if the piston group is smoking and the engine is using oil. Excess pressure in the first place “presses through” precisely this connection. If the crankcase ventilation system is clogged, the oil will also go through the “rear root” first of all.

Installing the rear main bearing

It is worth cleaning the ventilation system, the rear oil seal stops leaking.

The rear oil seal may be leaking due to worn crankshaft journals. Determine the wear of the necks by listening to the engine. With a sharp gas supply, a dull roar or knock is heard in the area of ​​\u200b\u200bthe crankshaft. The knock is very characteristic, it is difficult to confuse it with something else. Here, replacing the stuffing box will not help, the shaft needs to be ground.

Camshaft bed

Apparently, not all the differences between ZMZ 402 and ZMZ 24 were considered in this article. ZMZ also upgraded the cylinder block in the camshaft seat. On all early releases of the Volga GAZ 24, aluminum blocks had bushings for the camshaft. The problem is that the operation of the internal combustion engine with low oil pressure leads to premature wear of the camshaft bearings and the seat of these bearings.

Scheme of the camshaft of the ZMZ 402 engine

Replacing camshaft bushings is troublesome, but doable in garage conditions. ZMZ produced repair bushings that could be installed instead of worn ones, it was necessary to have a set of reamers and a lot of patience, time and accuracy. The shafts were successfully ground to repair size, and no major problems were observed.

Everything got worse after the Zavolzhsky Motor Plant decided to abolish the bushings, and decided to install the shafts directly in the body of the business center.

Such sleeveless blocks began to be produced after 1985. Moreover, this happened both at ZMZ 24 and at ZMZ 402.

After some time, the plant completely abandoned the bushings, which caused and still causes a lot of problems for the owners of the Volga. In the event of such a malfunction, there are two ways out - either give the BC to “plug in” to the factory where there is a milling machine, or change the block to another cylinder block.

Hex drive oil pump

On ZMZ 24 engines, the distributor drive is also the oil pump drive. The oil pump drive is a hexagon that drives the pump itself. Over time, the hexagon wears out and turns in the body of the pump, and if you do not monitor the oil pressure, trouble can happen to the motor - the crankshaft will knock, an overhaul will be required. Hex breaks happen if the oil in the sump freezes in winter. Therefore, oil pressure must be monitored carefully.

Camshaft gear

The knock of the gear indicates the wear of its teeth. It can knock for quite a long time, but it is better not to delay the replacement of the part. If the teeth break on the road, the car will not start and will not be able to go further. The car will have to be towed to the nearest auto repair shop.

Upper bushings of connecting rods (under the piston pin)

Under load, the connecting rod bushings tend to wear out. This is typical for many motors with "floating" fingers. Knocking due to worn bushings is not too dangerous if it has just begun to appear. But you should not delay the repair, as a result, the piston pin may burst. Then the consequences will be dire. The knock of worn bushings is similar to the knock of the timing gear, but differs in that it is clearly audible under load.

Price from 14 000 rubles.

Cylinder head ZMZ 402

Article: 402.3906562-00

ZMZ 402 is a four-cylinder engine manufactured by Zavolzhsky Motor Plant. The cylinder block of this engine is made from a specially reinforced aluminum alloy. The engine itself is famous for the fact that it can work at extreme loads, when others have already refused to work. Low sensitivity to overheating and excellent wear resistance with rough use. The engine is reliable as it is extremely simple in design and takes its roots from earlier engines of the late 50s. It was later replaced by ZMZ-406, but is still in use today.

  • Volume: 2.445 l
  • Compression: 8.2
  • Power at 4500 rpm: 100 hp

ZMZ 402 was installed mainly on cars of the Gorky Automobile Plant, such as Gazelle, Volga, as well as on cars of the Ulyanovsk family UAZ.

The ZMZ 402 cylinder head assembly is sold as a separate spare part. You can buy it from us, as well as immediately install it in our car service!

Under the designation ZMZ-402, there is a whole line of power units manufactured by the Zavolzhsky Motor Plant. These gasoline 4-cylinder engines are mainly installed in Gazelle and Volga passenger cars. You can find information about their use on minibuses "Latvia" and some models of the Ulyanovsk Automobile Plant.

History of engine development

The 402 engine has been installed on cars since 1958. At that time, it had a different designation - ZMZ-21A and ZMZ-24D, but it was still the same engine. The prototype was an even earlier modification, on which the designers worked in 1954-1955. Then it was a completely new version of the engine for the GAZ-56 car, which did not even leave the assembly line. The 402nd unit became known only in 1980.

The main representatives of the 402 line are:

  • ZMZ-402.10 as the main basic version for AI-92 gasoline.
  • ZMZ-4021.10, consuming A-76 fuel.
  • ZMZ-4022.10, which has a new type of ignition, the so-called prechamber-torch.

During the operation of 402.10 engines, they often tried to use cheaper fuel. To do this, by the forces of car owners, the engine was remade for gasoline with a lower octane number. As for the flagship of the 402 line - ZMZ-4022.10, there are opinions that the idea of ​​\u200b\u200bprechamber-torch ignition was taken from Honda's Japanese colleagues.

Since 1996, a younger and more modern brother 402 has appeared - ZMZ-406. For some time, both lines were installed on cars of the Gorky Automobile Plant. Now the 402 engine can only be found in spare parts.

Description and specifications

ZMZ 402 series engines are unpretentious in operation and quite easy to maintain. Petrol, with a carburetor, have 4 cylinders in a row. They were installed mainly on GAZ cars: Volga and Gazelle.

The working volume of the power unit is 2.445 liters, which allows you to develop a power of 100 liters. With. or 73.5 kW. The compression ratio is 8.2 - this allows the use of AI-92 gasoline. Cylinder diameter and piston stroke - 92 mm. The total weight of the unit is 181 kg. The exhaust system incorporates exhaust gas recirculation, which significantly reduces pollution environment and allows you to comply with the rules.

Components

The engine block 402 and the upper part of the crankcase are one piece and made of high strength aluminum alloy. Cast iron cylinders are represented by removable liners. For fastening the block head on the upper surface, 10 "bosses" are provided. At the bottom, the engine block is divided into 4 parts by partitions. They contain the main bearings of the crankshaft.

Each cast iron bearing cap is secured to the block with two 12mm studs. Since the boring of the block occurs together with the covers, they cannot be interchanged. Therefore, for convenience, they were assigned numbers stamped on all but the 1st and 5th.

A timing cover made of aluminum alloy is fixed to the front of the block. And to the back is the clutch housing. All connections are attracted by fastening bolts through paronite gaskets. 402 engine has an aluminum head common to 4 cylinders. Fastening to the block is made with ten 12 mm studs. The cylinder head gasket is made of graphite-coated asbestos and edged with a reinforced frame. Its minimum thickness is 1.5 mm.

Modifications 402.10 and 4021.10 have block heads of different thicknesses. This is due to the different volumes of the combustion chambers. In fact, the 402.10 head is obtained by milling the bottom edge of the 4021.10 head by 3.6 mm.

Special attention is paid to the maintenance of the car engine. After 20 thousand km, it is recommended to broach the head, as well as adjust the valve clearances.

Maintenance

In order for the 402 engine, whether it's a Gazelle or a Volga, it doesn't matter if it works for a long time and efficiently, it is necessary to carry out timely maintenance. The engine, as you can already see, does not have a complex electronic filling and does not require highly qualified maintenance. What points should be paid special attention to?


Tuning 402 engines

Given the age of the engine and today's increased needs, you can understand why many craftsmen are trying to improve the engine. "Volga-402" is a rather old modification, I want to update it. What can be done? More power is what the 402 engine needs. "Gazelle" and "Volga" will greatly benefit from this. There are several options for such tuning.

One of them is boring a block for larger diameter sleeves. If the native 402 block has sleeves 92 mm in diameter, then the bored block has all 100 mm, just like on the modern UMZ-4216. At the same time, new sleeves are also placed in 100-mm sizes. The main disadvantage of such an upgrade is the deterioration of the thermal regime of the cylinder block. After all, the walls have become thinner by the size of the groove. And this is as much as 4 mm.

In another embodiment, the increase in power is provided by grinding the head of the block. This increases the compression ratio, which allows you to switch to gasoline with a higher octane number. You can also increase the diameter of the exhaust pipe and slightly widen the exhaust manifold. All this will give the necessary plus 5-10 liters. With.

The most noticeable increase in power is up to plus 30 hp. With. - is the replacement of the carburetor with an injector. True, this is a rather troublesome and expensive procedure.

Other Ways to Increase Power

Simpler, but no less effective options would be:

  • flywheel groove;
  • replacing a standard piston with a lightweight one;
  • increase in valve diameters;
  • replacement of the standard K-151 carburetor with more modern analogues;
  • new tuning camshaft;
  • installation of more expensive and high-quality candles from a foreign car with the replacement of high-voltage wires;
  • use only synthetic or semi-synthetic oil in the lubrication system;
  • reconfiguring the exhaust system.

Summing up, it can be noted that the ZMZ-402 engine is increasing in power different ways. At the same time, a car with such a motor will never be racing. This is, first of all, a reliable and high-torque unit for workhorses.

Possible malfunctions

Consider possible options the main problems of the GAZ-402, the engine of which is no longer new and has problems.

  1. Doesn't start. There can be many reasons for this. Of the main ones, these are the problems of the carburetor and the fuel system.
  2. Unstable rpm, poor idling. Again, the problem is most likely in the carburetor or incorrect valve clearances.
  3. Engine overheating. Here attention is paid to the water cooling system. This is a thermostat, water pump and radiator.
  4. Oil consumption. In this case, the seals are checked first, and then the oil rings and valve seals.
  5. Knock in the engine. Most often, this cause is eliminated only by a solid engine repair.

Repair of 402 engines

With any operation, the engine 402 sooner or later starts to fail. You shouldn't be afraid of it. There are no eternal mechanisms, but there are good specialists and a wide range of spare parts. In this case, it is not necessary to wait for knocks that are unnatural for the unit. The indication for repair is a simple increase in oil and fuel consumption. In the GAZ-3110, the 402 engine, for example, should have a gasoline consumption in the city of about 13.8 liters per 100 km. The ZMZ-402 engine is quite easy to operate in the summer. When preparing it for the winter, you should first check all the technical fluids. This is engine oil, cooling, brake and windshield washer fluid. The oil should be changed to semi- or full synthetic. Pour antifreeze into the cooling system with required temperature freezing.

The weak link of winter trips is the carburetor. It needs to be configured in a certain way. Adjustment is made on a hot engine. Idling is set with a special screw. After tuning, it is important to practice the operation of opening and closing the carburetor choke.

Finally

402 engine is a quality product of the Zavolzhsky Motor Plant. More than half a century has passed, and he still continues to delight some car owners. Ease of operation, a large selection of components and inexpensive maintenance have determined the popularity of the unit for many years.

We remove the cylinder head for repair, for replacing the gasket under the head and for a complete engine overhaul.

We conditionally describe all operations on the engine, which has already been removed from the car.

Remove the wire ends from the spark plugs.

Loosen and remove spark plugs

Disconnect the crankcase exhaust pipe

We disconnect the hose of the vacuum regulator of the sensor-distributor of the ignition.

Remove the air filter housing and carburetor

With a socket wrench or a 10 head, we unscrew the six bolts of the block head cover

Removing the cylinder head cover

Remove the cylinder head cover gasket

Using a 13 wrench, unscrew the two nuts of the side pillars of the rocker axle

With a key or a head for 17, we unscrew in succession four nuts of the racks of the axis of the rocker arms.

We remove the axis of the rocker arms from the studs (you can gently pry with a screwdriver).

We take out eight push rods in turn. In this case, you need to mark the rods or put them in a row and remember the position in order to install all the rods in their places during assembly.

With a head of 17, we unscrew ten nuts securing the head in succession.

It is advisable to unscrew in the reverse tightening sequence (see the figure for tightening the nuts).

We take out the cylinder head (When removing, do not pry the head with a screwdriver or other tool in the mating plane)

15. The sequence of tightening the cylinder head nuts is shown in the figure.

We install the head in the reverse order, after lubricating the cylinder head gasket with graphite grease and putting it on the block studs.

We tighten the block head nuts in two stages:

1st stage - 40–60 Nm (4.0–6.0 kgf m);

2nd stage - 83–9.0 Nm (8.3–9.0 kgf m).

I started the assembly by replacing the tank with a new one from a gazelle, screwing a fitting into it by 18:

In the fitting, I went inside with a drill for 15. Feel the difference:

However, the funny thing is that it did not become warmer in the car in winter. The reason I see in growth Engine efficiency after capital. That is, before the capital, the consumption in winter was more than 25 liters, and even with a thin fitting, there was enough heat, after the capital, the consumption fell one and a half times, which is why the heat became one and a half times less. So, despite the increased fitting, it did not become warmer in the car. However, as I understand it, if the fitting had not been changed in winter, it would have been somewhat cool.

In the thermostat, I filed off casting defects with a file, which will improve the coolant circulation by a fraction of %:

When unscrewing the thermostat cover, one of the bolts broke off, so I cut the thread there by 10 and replaced the bolts:

I also slightly “fractured” the oil supply channel from the hole to the rocker arm axle support (seen in the photo), there were small burrs:

There was no noticeable wear on the sleeves, although during the initial grinding, when all the pistons were in the central position, the force on the barrel organ increased significantly, so wear did take place and one hundred thousand km did not pass without a trace for the sleeves. There was no wear on the pistons, only minor abrasions, probably due to carbon deposits:

There were no problems with replacing the rings, old ones on top, new ones on the bottom - buzuluk (Czech Republic):

The funny thing is that the old rings did not spring much worse than the new ones, but they had wear in the section. After replacing the rings, we install the piston back, not forgetting the correct orientation - the inscription is forward - forward, oddly enough, the hole in the connecting rod should pee towards the collectors, the passenger:

We put the nuts of the connecting rods on threaded sealant. We plant the lid as it was. Before driving the piston, first we tap the mandrel around the perimeter, and then gently push the piston with the hammer handle.

Next, change the stuffing box. I bought a cheap one for 15 rubles, I changed it only in the lower holder, since I did not remove the crankshaft. Despite all this, this 15-ruble stuffing has been holding TNK 5v40 synthetics for a year with periodic engine spin-ups up to 5000 rpm. As far as I understand, the packing flows with large beats, with strong wear of the necks and liners.

The next step is to install the cylinder head on the studs. I wound fum tapes, due to the fact that it is Teflon (fluoroplastic), and it is extremely chemically resistant and quite heat resistant. In general, I wrap a fum-tape on all the studs / bolts that are prone to souring, it will tear in loaded places, and fill the cavities, which is why rust does not form in them. The fum tape itself is not going anywhere:

Also, absolutely all the studs in the cylinder head, I also screwed back onto the fum tape.

I installed the gasket with triangular windows. From the factory it was the same:

Gaskets with thin round holes do improve the coolant circulation somewhat in the region of 3-4 cylinders, but I recommend them to those who like to drive in XX, and for whom 2500 is exorbitant speed. While driving, I try to keep the engine between 2 and 3 thousand rpm, I have 1000 rpm at idle.

I also applied a little know-how, wrote on the head the order of tightening the nuts :):

Tightening step by step. First tightened by 9kg. And it was not in vain that he immediately filled in antifreeze:

Promptly stretched for 10 kg, the leak stopped. All the same, it’s better not to take off your head with a crowbar :). He stretched his head a second time after the first warm-up the next day and then a week later. For dessert, as expected after 1000 km. After each broach, of course, we adjust the valves.