DIY gas 402 engine repair

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Neelmoo 08 Nov 2016

Dear forum users. Your advice is vital because the gazelle is the true breadwinner of the family.

On the way, white smoke came from under the hood and the car lost power. Tasol squeezed out.

Towed the car to the gas service and the verdict: the gasket and the head must be sanded.

Plus they say the piston is wobbling and it is necessary to sort out the engine. The price of the work is a bulkhead 35,000r + spare parts up to 20,000. Perhaps, according to their words, there may be additional costs when they open and see up to 20-30k - a total of at least 50,000 and above

The engine is a zmz 402 old gazelle, money for a new and even used one. no. We can barely make ends meet. Some people advise looking for an engine on parsing. They say that from 20,000 + installation 13,000. Total 33,000+.

I'm afraid of a divorce on the part of the service, I have no acquaintances. What to do in this situation and what would you advise?

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Valery (69) 08 Nov 2016

White smoke went up. Did you look at the thermometer? How much was the coolant temperature? They said that the piston was swinging. Did you swing it yourself? You can buy a pig in a poke on parsing.

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Neelmoo 08 Nov 2016

I didn’t pump it myself. The temperature, according to the driver, was normal. The driver drives this gazelle. The service said that the belt was loose and not on the rollers and the car was overheated. I agree with the analysis, but 55-75,000 rubles for the bulkhead is not a pity, but they simply do not exist.

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Valery (69) 08 Nov 2016

I didn’t pump it myself. The temperature, according to the driver, was normal. The driver drives this gazelle. The service said that the belt was loose and not on the rollers and the car was overheated. I agree with the analysis, but 55-75,000 rubles for the bulkhead is not a pity, but they simply do not exist.

It's good that there are two of you. You will need two torque wrenches (5000 rub.) And a manual for disassembling and assembling zmz-402. You can find a good used cylinder head (look for 421). It is better to do the cylinder head with a specialized workshop (service), do the rest yourself.

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Neelmoo 08 Nov 2016

Grind the head, change the thermos, fix the leaks and rush off the money to earn the caprem.

We'll sort it out ourselves. There is a chance that after replacing the gasket and the head point, you can still drive

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Valery (69) 08 Nov 2016

We'll sort it out ourselves. There is a chance that after replacing the gasket and the head point, you can still drive

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IvanSPb 09 Nov 2016

why two torque wrenches? One is it?

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ilian32 09 Nov 2016

As a rule, two keys are designed for different moments from low to high. Look here for a guy with the nickname Slash98, it seems, really adequate people and repairs conscientiously. A small parting word - urgently change the gasket between the steering wheel and the seat.

One key - don't talk nonsense. what are there from low to high.? Key for example from Matrix - adjustable from 15 to 300 NM. and King Tony and Usag and Sata and Snapon are all practically the same. Why 2 keys?

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alexander1975 09 Nov 2016

402 dvigun on a gazelle? they are sold in an immeasurable amount of 10-15 kilo rubles. while the car is standing-start-warm-listen. I don't see a problem at all.

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rusgg 09 Nov 2016

We'll sort it out ourselves. There is a chance that after replacing the gasket and the head point, you can still drive

there is always a chance
Only it is not clear which one, maybe almost zero, and maybe more.

At least if the car goes, it will go, and if not, then change the head at least

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aca300 09 Nov 2016

I would check the plane of the head (repaired if necessary) and change the gasket. Don't get into the block yet. If everything goes well, then keep rolling.If there is a problem, then the capital, but the head will already be made. The main thing is not to overheat it a second time.

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GoldeN 09 Nov 2016

Mill your head, put the gasket yourself, everything is simple, in principle, you can, sales without a torque wrench, until it was pulled with an ordinary extension cord by hand without any pipes, how much power was enough without fanaticism, (like without a pipe you can't pull out the studs with Hercules be). Just look at the tightening order. And it is desirable to stretch through 3 thousand again. If the slurry does not go anywhere further, it’s still much more than 10,000 will pass. If there are further problems, do not do this miracle, throw it out and find the Volga with a decent 406 thousand for 40, rearrange and go further.

I now took for myself for 5.5r 402 prepared for the capital of the 1st completeness (new pistons, rings, bored sleeves, new connecting rods, bore-out shaft + spare, 3 pumps, a set of gaskets, cylinder head from repair), I will collect it on the compressor, and a neighbor in garages 5 working engines handed over 2.5 r each for acceptance

Post has been editedGoldeN: 09 November 2016 - 11:20

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Alexander Nov 09, 2016

I like these people!
We can hardly make ends meet - and a hired driver is driving! which on your car and your problems

Post has been edited Toyota007: 09 November 2016 - 18:06

Take mine for 12 sput. 7 thousand after the capital, I did not carry more than 500 kg. I'm collecting 405 for myself.

I like these people! We can hardly make ends meet - and a hired driver is driving!

My neighbor is the same! Jo. and naked and on KAMAZ put a mercenary, himself in scrap. Repaired often, often

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Ram Nov 09, 2016

With a 402 engine, you can buy the Volga for 20 sput and transfer the engine, sell the rest of the Volga.

Or look for a doorkeeper, he will sort out in a couple of days, spare parts for 10 thousand at most!

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Alexey595 09 Nov 2016

I had a similar one. I found my head for a threefold under the 80th, Protochit up to 94.4 under the 92nd. I rubbed the valve and changed the caps. It took a five for everything.

And here it is still not known whether the cylinder head needs to be changed. You can just grind, align and ride. Then everything will fit in a couple of thousand.

I like these people!
We can hardly make ends meet - and a hired driver is driving! who doesn't give a damn about your car and your problems

Well, what's wrong - that the hired driver was driving - and what is the reason for sarcasm?

If, for example, he cannot drive his sharpener himself - for a number of reasons. and there are many of them. Or what if a hired car was driven by the owner of a car like a gentleman and is not worthy of respect?

Yes, maybe the driver looks at him as if he were a god - for the same opportunity to work and bring a piece of bread to the family, and where did you get the idea that the driver doesn't give a damn? Judging by the fact that they sang in this service - there are still nightingales, that's where the real hucksters are. Ready to rip off the last one and do it **!

It's a pity that a guy far from me would help him.

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Valery (69) 09 Nov 2016

One key - don't talk nonsense. what are there from low to high.? Key for example from Matrix - adjustable from 15 to 300 NM. and King Tony and Usag and Sata and Snapon are all practically the same. Why 2 keys?

I suppose there are 60-320, but there are efforts and 40-50. There are keys 0-300c +, so it costs like a 402nd engine.

there is always a chance
Only it is not clear which one, maybe almost zero, and maybe more.

At least if the car goes, it will go, and if not, then change the head at least

Actually indications for overhaul 2 - this is an increased consumption of gasoline and / or oil. In principle, everything. Any engine malfunction (and not only, as well as chassis, for example) one way or another will lead to an increase in fuel consumption. At the same time, the car will not lose in dynamics (well, unless everything is extremely neglected, like a burnt-out valve piston). For any car, the manufacturer indicates the normal consumption of both gasoline and oil. In the case of the Volga with ZMZ 402, gasoline consumption in the city should be 13.8 liters per 100 km, and oil should be consumed no more than 250 grams per 100 km.

In my case, the consumption was 25-30 liters, but the oil had to be topped up by a liter per month, with a mileage of less than 400 km. Gasoline consumption was measured by the odometer. As further developments showed, in addition to the wear of the engine itself, a slipping clutch and a wedging brake pad, as well as a muffled EPHH system, also contributed to the increased consumption.

The capital was made a year ago, upon completion of the run-in, it turned out that in winter, with normal driving (without slipping), it fit into 20 liters, in summer the consumption was 14-16 liters when driving with a moderate degree of aggressiveness. During the run-in, the problem of oil leaks was actively solved and by the time the run-in was completed, the engine was switched to synthetics, which it still drives.

The oil pressure before the capital was satisfactory, so I did not plan to remove the crankshaft. Nor did I plan to change the earbuds. From the spare parts, I took a set of valves:

New valve springs. It is imperative to change them with capital, Evgeny Travnikov constantly repeats this, they say tired valve springs squander power at high speeds. It seems to be true, after 3000 the motor with new springs began to pull much more fun.

A re-turning was also planned, for which a set of bushings was purchased.

A set of gaskets was also purchased for the overhaul of ZMZ Zolotaya Series. This set turned out to be a rare gamma, so I advise you to buy separately the valve stem seals, the front crankshaft oil seal, crankcase cork gaskets, valve cover and pusher covers. For all other gaskets, I advise you to buy oil-resistant paronite and cut the necessary gaskets in place yourself.

From the tool you will definitely need:

Torque wrench for 12 and a head for 17 is required.

The mandrel for pressing on the valve stem seals will not interfere:

Be sure to need a 9mm sweep:

The valve dehydrator will make life easier and save the bushings:

One of the most expensive items is cutters:

To remove the cylinder head, first remove the axis of the rocker arms, then carefully unscrew 10 nuts. I had a couple of nuts creaking, so you need to unscrew it smoothly. Important! In order not to distort the cylinder head, the nuts must be unscrewed in the same order as when tightening, little by little. That is, first we pull off the nuts from their place. Then we sequentially unscrew all the nuts, unscrewing them by a third of a turn. Further, all the hope is that the collective farm with the previous installation of the cylinder head was not (such as a stuck solid oil). However, even in the absence of a stuck gasket, there will most likely be a problem with the penultimate hairpin on the passenger side:

The next stage of the overhaul is the removal of resinous deposits from the parts. This is how the cylinder head looked a year before the overhaul, after 1.5 years on semi-synthetics:

Washing was carried out with dishwashing detergent (any will do) using a toothbrush. The technology is as follows - we drip with dishwashing detergent and with three toothbrushes, wipe it dry like the slurry turns black with a paper napkin. And so on, so almost all the details were washed away:

First of all, the washed cylinder head must be sanded:

The combustion chamber was covered with a thick layer of carbon:

Next, remove the old valve stem seals. I didn't have much oak, and a couple were generally cracked:

The next step was to turn over. I wanted to use the technology of Evgeny Travnikov:

The next stage of cylinder head repair is the trimming of the saddles. It seemed to me that only a 45-degree chamfer is cut from the factory, but I cut all 3, which is why the valve should close more tightly and gas exchange should improve. I heard a lot about the hardness of the cylinder head ZMZ 402 saddles, but with the above set of cutters, my saddles were cut quickly and easily. The central chamfer was made in the region of 1 mm so that after lapping it would increase to the prescribed 1.5 mm.

The next step is lapping the valves - this is the most tedious step. I didn't bother much about checking with diesel fuel, etc. assessed visually by an even pattern around the circumference of the saddle.Do not forget to sign the valves so as not to confuse them during assembly.

Also, to improve gas distribution, I grinded down the steps at the valve seats:

At the end of the cylinder head repair, we press on new valve stem seals using a mandrel. IMPORTANT! Before pressing the MSC, put on the lower valve plates, then they will not fit 🙂... After that, you can dry out the valve. Let me remind you once again that the springs must be changed during a major overhaul. The old valves were dirty and worn out - they had both scuffs on the stem and did not protrude enough above the plate, that is, as the rocker arm wears out, it will begin to press not on the valve, but on the plate:

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

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

I also slightly "screwed up" the oil supply channel from the hole to the support of the rocker arm axis (seen in the photo), there were small burrs:

Then he proceeded to replace the piston rings. Before that, I carefully scraped off the carbon deposits from the piston (it turns out to be aluminum):

Next, we change the gland packing. I bought a cheap one for 15 rubles, changed only in the lower holder, since I did not remove the crankshaft. Despite all this, this 15-ruble packing has been holding TNK 5v40 synthetics for a year with periodic engine promotion up to 5000 rpm. As far as I understand, the packing flows with large beats, with strong wear on 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 wind fum tape on all pins / bolts prone to souring, in loaded places it will break and fill the cavities, which is why rust does not form in them. The fum tape itself is not going anywhere:

I put the gasket with triangular windows. From the factory there was the same:

I also applied a little know-how, wrote on my head the procedure for tightening the nuts 🙂:

The primary grinding of the rings was carried out with a barrel organ (crooked starter), that is, when the cylinder head was not yet installed, I poured oil from above into the sleeves and twisted it. That is, what a pause stood out, I approach - 50 revolutions. It became especially tight after replacing the packing, in total I did it with my hands in the region of 500-1000 rpm, as a result, the engine started with a starter without straining. I ran in the same oil that I drove to the capital - semi-synthetics TNK 10v40. While driving, I tried to keep 2100 rpm without spinning more than 2500. Without any dynamic overtaking. Having driven around the city for a week, then made a circle of honor around the city, about 80 km along the bypass road. At the same time, I was driving strictly 2100 rpm in 5th gear - this is about 80 km / h on the railway station, according to the speedometer it was 90. All the time I was running in I was at war with oil leaks, and by the time 1000 km was completed all leak channels were eliminated and I switched to synthetics with a clear conscience ...

The ZMZ 402 engine, which was produced at the Zavolzhsky Motor Plant, became a real legend in the domestic automotive industry of an entire era. It was installed on many car models such as Volga, UAZ, Gazelle and others. But, since the power unit has ceased to be produced, and its operation is carried out to this day, then periodically these engines need to be repaired.

Any engine wears out during operation, and this happens not only with internal elements, but also outside. This indicator is influenced by many factors that destroy the engine. So, let's consider the reasons why the ZMZ 402 engine needs repair, especially with regard to capital restoration:

The process of carrying out repairs, including overhaul, for the ZMZ 402 engine and its modifications, is similar to other power units of the series. All power units manufactured and manufactured by the Zavolzhsky plant are similar in design characteristics, and therefore repairs are quite easy. So, let's look at how to repair the ZMZ 402 engine with our own hands.

Repair of the ZMZ 402 engine begins with the dismantling of the power unit. The process is fairly straightforward, but four-handed is recommended. But, there is one difference, if the internal combustion engine is removed from the Volga, then this is one sequence of procedures. As for the 402 Gazelle engine, here the dismantling technology is slightly different. In order not to get confused, consider the classic process of removing a motor from a Volga car.

So, what sequence of operations needs to be performed by the motorist, what to remove the engine from the vehicle:

1. First, the battery is dismantled and its shelf is unscrewed.
2. Next, you need to remove the air filter and carburetor.
3. Disconnect the front pipe from the exhaust manifold.
4. We unscrew the spark plugs, remove the wires and the distributor.
5. We drain the engine oil.
6. Disconnect the fuel system.
7. Remove the fan impeller.
8. We dismantle the starter and generator, as well as the wiring associated with them.
9. Disconnect the clutch from the gearbox.
10. Dismantle the oil filter housing.
11. We remove the radiator and pipes of the cooling system.
12. We dismantle the intake and exhaust manifolds.

Further, when everything is disassembled, we completely remove the hood so that you can be unhindered, pull out the engine. We dismantle the power unit by hooking it onto a hoist or winch. Now, we install the motor on a special stand, if there is none, then on pallets and proceed to disassemble it. The motorist needs to disassemble his engine completely.

To do this, remove the parts in the following sequence: clutch, valve cover, oil pan, cylinder head, oil and water pumps, pistons, yoke, crankshaft. Now you can start the procedure for diagnosing the condition of the parts.

Diagnostics of engine parts begins with an inspection of the integrity of the cylinder block and crankshaft. If necessary, the body can be welded with special welding. If the block is very susceptible to destruction, then it should be replaced with a new one.

The next step in the diagnosis is the measurement of the cylinders. The standard for ZMZ 402 is the size of 92 mm. But, if there is an elaboration on the walls, scratches or shells, then you will have to sharpen it to the next size. And if the measurement showed that the walls have already been repaired, then it is imperative to sharpen it until the next one, since the cylinders have a depletion and it must be eliminated.

Consider a table of the dimensions of repairs for the power unit 402 and its modifications:

Repair of ZMZ-402. Disassembly and troubleshooting

The internal cavities of the engine were heavily contaminated with a mixture of grease and soot, almost a centimeter under the valve cover. When opening the crankcase, the main nut was unscrewed.

The nut was stored in a pallet.

The stuffing was brought up in order, it was installed with a Christmas tree in rotation, i.e. vice versa.

The exhaust valves are flared with fungus.

The camshaft upset most of all, on 4 cams there are nicks, the cams are sharpened by 1 mm.

On the intake valves at the top of the cut.

To measure the stiffness of the springs, such a device was made.

Based on the results of parsing the camshaft for replacement, grinding the knee, valves for replacement. I will cut the head of the ZMZ-402 under 92 gasoline.
Internal springs are within tolerance, external springs are rather weak (46 mm, 23-25 ​​kg).
The piston is in the tolerance, at least not to change something, I will change the ring current.

So, at the moment, I have assembled a block. First of all, I eliminated factory errors in the manufacture of the block, the channel after the pump is clogged with flash and casting defects.

But after using the file, everything goes away.

Next, we unscrew the plugs of the oil channels, and clean the insides with a wire and a compressor; in three channels, the remnants of drilling were found, it looks like they are still from the factory.

We level the sharp edges on the oil channels of the crankshaft so that they do not cut off the liners, the main thing here is not to make a bump along the edge.

I spin the crankshaft, not over my head, but the crankpin plugs.

It got from the crankshaft.

We put a knee and drive in the piston, grease all the mating parts with oil, which I will then fill in for running in.

Tie on two clamps and strips of sheet metal 30 * 290mm

Installation of the ZMZ-402 camshaft.

I put the adapter on the Zhiguli filter, drilled out the oil channel, it was very small.

Adapter for Zhiguli filter.

The pulley spread apart had to be knocked down and grabbed.

I painted the covers from ZMZ-402.

On the left is the Volgovsky bracket, on the right is the UAZ one, for comparison

A Fenox basket was selected, driven by any UAZ one for the desired shaft (they are also different).

For comparison, on the left is an old Volgovskaya, on the right is a new one, at the back there is a lever. I will not say exactly where it comes from from an UAZ or GAZ, 6 springs, seemingly more powerful than from an UAZ. I read from the reviews that the diaphragm link is weaker than the lever one, a small test stepping with the heel into the place of pressing the release bearing with my stunted body of 100 kg, I can say that the old Volgovskaya and the lever link bent by 1-1.5 cm, and the new nifiga did not bend.

I read that the flywheel on the ZMZ-402 is lighter than on the UAZ (8 kg versus 13 kg), well, figs knows, maybe I have it from old age, but it weighs 13 kg.

And his diameter is like this.

It is desirable that the bell be universal, like mine.

Summarizing, we can say that to introduce the ZMZ-402 from the Volga to the UAZ, it is enough to buy a pressure plate and front engine mounting brackets. Well, the exhaust has to be altered, the gas pedal control… these are trifles.

I also had to change the ring gear, knocked down the old one with a hammer, put the new one in the oven for 10 minutes at 250 degrees, like ten minutes. I lubricated the flywheel with a thread lock in advance and put on a crown. Collected after cooling.

It happens that antifreeze runs away through a hole in the block along a hairpin, this one

Secret hole threaded at 10.

I did not check, but simply screwed a bolt in there.

Collected the cylinder head. The head was ground under 92 gasoline, cut off 3.5 mm, the height of the cylinder head was 98 mm, it became 94.5 mm (standard 94.4 mm).

The outlet to the stove, the so-called tank, in the rear of the cylinder head rests against the wall of the engine compartment and needs to be removed, and the question arises where to get the outlet to the stove. Well, if there is a sensor in the upper part of the cylinder head, then the question disappears, but in this place I had only a technological influx of aluminum. In short, there is no hole. But the absence of a hole will not stop normal boys, I need to do it, I got married like that in general. Okay enough demagogy closer to the point.
The cylinder head was like this:

I took a 19mm drill bit (I had to take it for 18mm, but it worked out fine anyway) and half-inch taps for pipe threads, they can be seen in the photo, and rushed.

We drill and cut threads, everything is just enough space.

Then I checked the oil channel, it did not coincide a bit with the block, it was filed with a file.

Grinding the mating plane.

I checked the input-output channels for coincidence with the spider, sawed off.

Not a scratch remained on the valves from the purchased lapping, although the belt on the saddle was already packed almost 2 mm, I repeated it with a homemade one made of abrasive, it went a little.

But on the rest, I did not achieve the same effect, I spilled it with a solvent, it didn’t seem to flow and was dry.

In the set of gaskets there were gaskets for everything, I had to do it myself around the back plug of the cylinder head. It is convenient to hit holes with a sleeve 7.62,

For stuffing the caps, a brush came up clearly.

The passage diameter of the angle 15 is approximately 14.5 mm, the tank is 9.5 mm, i.e. the passage in the corner is more than 2 times.

I drove the holes for the engine studs with a 13 mm drill, cleaned out a lot of dirt and removed the aluminum flattened to the thread.

Ideally, the guides would be changed (clearance 0.5 with a max tolerance of 0.25 mm), but it is expensive, and there is no suitable set of tools. On sale, the scans are bad.

The engine is assembled and dries up. The head is screwed on, the valves are adjusted. I drilled a hole in the pump for a half-inch brush so that the coolant outflow from the stove was equal to the inflow.

I drove a sleeve from the shock absorber into the tee to reduce the flow of fluid in a small circle, so that the pump sucks more from the stove.

I screwed all the nuts, pins and bolts onto the thread lock, where it is red, where it is blue, something I like it very much lately.

Disassembly, assembly and troubleshooting of ZMZ-402 completed.

No other domestic engine has generated such a number of dense prejudices, persistently passed on from generation to generation, as the good old ZMZ 402 engine. Everything would be fine, but blind faith in all these fabrications blocks the road to a number of simple but effective improvements that can turn the old man into a unit that is quite suitable for modern dynamic driving. Whether it is worth doing this or not is a separate question, but I think there should be at least an opportunity. Therefore, let's start looking for the truth.

1. ZMZ-402 is older than mammoth excrement, has a pedigree from the Dodge of the 30s!

5. The only real way to cheer up the 402 is to introduce a 100mm piston into it, turning it into a 410.

6. A good way to increase the power of the 402nd is to remove the steps at the junction of the cylinder head with the manifold and polish the channels to the mirror.

7. ZMZ-402 is too gluttonous.

8. If oil does not flow from the 402, then it is over.

9. Synthetics cannot be poured into 402, the packing does not hold it.

10. After the capital, the 402nd lives no more than 50 thousand km.

11. If the head is milled to a height of less than 94mm, it will be possible to drive only on 98 gasoline.

12. To transfer 4021 2401 to AI-92, it is imperative to mill the head, otherwise the valves will burn out.

13. The best way to improve fuel efficiency is to supply a Zhiguli carburetor.

14. The engine with the "modern" k-151s is more powerful and more economical than with the outdated k-126gm.

15. After replacing the oil filter cup with an adapter, you cannot use Zhiguli filters, you can install only from ZMZ-406.

16. Most foreign-made radiators are not suitable for ZMZ-402 due to the smaller diameter of the leads: there will not be enough throughput.

17. Oil cooler 402 is not needed. Or is it needed?

In this video of the repair 402 engine, the author tells in detail how to disassemble and repair it.

Shows how to remove the valve cover correctly. It also draws the attention of viewers to the condition of the barbells as one of the frequent breakdowns and explains why they need to be changed.

Step by step disassembling the engine, the author draws his attention to the fact that all mounting parts must be in car oil. When disassembling, all channels must be cleaned, and if there are potholes, they must be sharpened. You also need to pay attention to the valves, they must be clean and not burnt out.

As it turns out on a video campaign, the whole reason for the breakdown is a malfunction of the camshaft drive gear.

The author does not forget to tell how the oil pump is removed, how the flywheel and pulley are removed correctly.

Draws attention to the piston, apparently, it has recently changed, although one of the rings is already broken. This suggests that the previous master overdid it a little.

The author carefully demonstrates the disassembly of the 402 engine down to the smallest details and elements. Shows how and how the parts are removed correctly, tells how they work, why they serve and what can cause them to break down. This video can serve as a good lesson and example in order to deal with the engine yourself at home.