Proper installation of ignition on the engine ZMZ-402

Engine. ZMZ-402The GAZ-24 and GAZ-31029, as well as the Gazelle trucks, are classic gasoline units with a lower camshaft, and despite their reliability and simplicity, they are highly sensitive to the quality of spark system tuning. Contact ignition systemThe stains that are most commonly found on these models require regular maintenance and precise adjustment of the gaps.

Incorrectly setting the moment of ignition of the mixture leads to a whole bunch of problems: from increased fuel consumption and loss of traction to burnout of valves and pistons due to detonation. Owners of old Volga and Gazelles need to clearly understand the physics of the process so that the engine works smoothly and gives the declared power. Oz. (The ignition angle) is unacceptable.

In this article, we will take a closer look at the tuning process, from checking the gaps in the interrupter to the final adjustment by strobe or by ear. 1-2-4-3 dictates a certain sequence of actions and how to avoid common errors in the maintenance of the trambler.

Preparation and clearance verification

Before you start setting the angle of advance, you need to make sure that the mechanical part of the ignition distributor is in good working order. interrupterThe junctions wear out over time and become covered with soak, and if the gap between the contacts is too large or small, the spark will become weak or disappear altogether, making it impossible for the engine to function properly.

To check, you will need to remove the trambler lid and visually assess the condition. contact groupThe nagar is easily removed with a topfill or special grinding paper, but deep sinks require replacement of contacts. After cleaning, be sure to blow the insides of the case with compressed air to remove dust and wear products.

⚠️ Warning: Never try to clean the contacts with sandpaper with a coarse abrasive or a file with a large notch - this will violate the flatness of the surface, the spark will be unstable, and the contacts will start to burn even faster.

The key is the gap between the contacts in the open state. ZMZ-402 It must be strictly 0.35-0.45 mmAdjustment is made by turning the screw of the fixing of the strut of fixed contact and moving this strut with a screwdriver. Once the correct gap is installed, the screw tightens reliably.

• 🔧 Remove the lid of the distributor and the runner, check the absence of a backlash shaft.
• 🔧 Clean the contacts of the interrupter from oxides and soda, check the elasticity of the spring.
• 🔧 Set a gap. 0.4 mm (average) and turn the crankshaft by two turns to control the stability of the gap.
• 🔧 Lubricate the lubrication filler of the trambler roller with a couple of drops of engine oil, but do not pour it.

Remember, the condition of the capacitor also affects the system, and if it's broken, the contacts will always spark and burn, and you can check it by connecting a capacitor that is in good condition, and if the motor is working better, then the old element needs to be replaced.

Cylinder operating order and numbering

The foundation for the correct installation of ignition is an understanding of the order of operation of the engine cylinders. ZMZ-402This four-stroke unit has a specific circuit, different from many modern engines. The cylinders are numbered from front to back (from radiator to cabin), and the ignition of the mixture occurs in a sequence. 1-2-4-3.

It's important not to confuse the order of the cylinders, and it's this sequence that dictates which direction the distributor rotor rotates and which sequence to put high-voltage wires on the trambler lid, and if you make a mistake in connecting the wires at least one stroke, you'll sneeze into the carburetor or silencer, and you won't be able to start.

When we set the spark moment, we focus on the first cylinder. VMT (Upper Dead Point) at the end of the compression stroke, there should be a spark, and for this purpose, special marks are applied on the pulley of the crankshaft and on the front cover of the engine.

cylinder	tact	Action.	Position of piston
1st	Compression	Sparkling	BMT (end of bar)
2nd	Inlet	Intake of mixture	NMT → VMT
3rd	Release	Emission of gases	BMT → NMT
4th	Work course	Combustion (after 1st)	BMT (after 1st)

To find the compression stroke in the first cylinder manually, turn the spark plug and close the hole with your finger or cork. Slowly turn the crankshaft behind the ratchet or key. When you feel the pressure of air coming out from under your finger, the piston went up in compression, at which point the pulley tag should approach the mark on the lid.

Why is compression stroke important?

If you set the ignition on the exhaust stroke (when the piston also goes up), the spark will pass when the valves are open. The engine will not start, and if you try to scroll the starter, you can clap into the intake manifold.

Basic timing setting

The initial ignition angle (IE) setting process requires care and care. The engine must be silenced and the ignition key removed from the lock. Your task is to match the tag on the crankshaft pulley with the tag on the front cover of the engine corresponding to the required advance angle.

For engines ZMZ-402, running on gasoline AI-92 (formerly AI-93), the factory label usually corresponds to 5 degrees. If you use AI-76 (A-76) gasoline, the label should be combined with the risk denoting the risk. 12 degrees.The use of low-octane fuel with early ignition will cause a strong detonation.

When you combine the tags, loosen the octane corrector (the plate of the trambler body mount) so that you can freely rotate the distribution body. Turn the body counterclockwise (when viewed from above) until the runner comes into contact with the first cylinder on the lid. Then, without turning the shaft, carefully turn the body clockwise until the interrupter contacts click.

• 🎯 Combine risk on the pulley with risk 5° on the lid (for AI-92).
• 🎯 Weaken the screw of the octane correction plate attachment.
• 🎯 Set the runner opposite the contact of the 1st cylinder.
• 🎯 Turn the trambler body until the contacts are opened (checked by the control lamp).

Lock the tramblor body in this position with a screw, but don't tighten it to the end so that there's still a possibility (thin tuning). Now you can put the lid on, connect the center wire and try to start the engine. Initial start can be difficult, because it's just a rough setup.

Adjustment by hearing and dynamics

After the initial start, fine adjustments must be made. Oz. This method, often referred to as “audible adjustment”, is classic for carburetor engines and allows you to tailor the ignition to a specific engine instance and fuel quality.

Accelerate the car on a flat stretch of road to speed 40-50 km/h In a direct transmission (usually 4th), press the accelerator pedal to the full stop, at which point you should hear a short-term, ringing detonation ("fingers knock"), which stops after 2-3 seconds or as acceleration occurs.

⚠️ Warning: If the knock lasts more than 3 seconds or is heard constantly during acceleration, the ignition is too early. This is dangerous for the piston group! Immediately turn the trambler body clockwise (late ignition).

If you push the gas hard, you don't detonate at all, and the car accelerates sluggishly, then the angle of advance is too late, in which case the mixture burns out already with the exhaust valves open, which leads to overheating of the engine and a drop in power. You need to turn the trambler body counterclockwise (early ignition).

The ideal condition is when a sharp throttling can be heard a light, fast-decaying metal ringing, which indicates that the front of the flame is spreading at an optimal speed, using the energy of the fuel as efficiently as possible. Once you find the "golden mean", securely fix the trampler.

Using a strobescope to fine-tune

For owners seeking perfect accuracy, it is recommended to use strobeThis device allows you to visualize the position of the tags on the engine running and eliminate the human factor in determining the moment of spark, connects the strobe to the first cylinder (clamp on the high-voltage wire) and to the on-board network.

Start the engine and let it warm up to operating temperature. Idle must be stable. Direct the strobe flash to the pulley of the crankshaft. If the ignition is set correctly, the tag on the pulley should "freeze" against the risks. 5° or 12° depending on the fuel) on the stationary part of the engine with the engine running at idle speeds.

The advantage of the strobescope is that it shows the work centrifugalWhen you increase the engine speed (click carefully on the gas), the tag should shift to the front (right), which means that the automatic trambler is working and adds an angle of advance as the speed of the crankshaft increases.

The order of connection of the strobe:
1. Red wire (+) → Plus battery or generator.
2. Black wire (-) → Engine mass (bolt on the block).
3. Inductor clip → It is superimposed on the high-voltage wire of the 1st cylinder.
4. Turn on the device, direct the light to the pulley.

If the mark does not shift or shifts chaotically when the speed increases, this indicates a malfunction of the centrifugal regulator (jammed loads) or vacuum regulator (broken aperture). In this case, mechanical adjustment of the angle will not give full effect, the tramblor itself will need repair.

Typical errors and troubleshooting

Even experienced masters can make mistakes when setting up the ignition system ZMZ-402One of the most common problems is the ignition angle escape after fixation, which often happens if the octane correction plate mount screw is not tightened enough or the thread in the body is ripped off.

Another common problem is that the vacuum regulator is not connected correctly, and the hose from the vacuum advance regulator must connect to the lower hole of the carburetor (on the throttle side), where the only thing that gets diluted is when the throttle is opened, and if you mix up the hoses or connect it to the idle channel, the engine will become unstable.

• 🚫 Overheating of the engine: check whether the ignition is too early and the thermostat is correct.
• 🚫 Failures during acceleration: check the integrity of the vacuum regulator diaphragm and the purity of the jelly.
• 🚫 Difficult start: Perhaps the spark slips too early or too late, or a runner is pierced.
• 🚫 Contact burnout: check the condenser and the quality of the connection of the engine mass to the body.

And the quality of high-voltage wires is also important, because older cars often lose their properties and the spark goes away, especially in wet weather. Visually inspect the wires in the dark with the engine running, and if you see light music (sparkling on the surface of the wire), you need to replace them.

⚠️ Warning: When replacing the trambler with a new one, be sure to check the length of the shaft. The ZMZ-402 and ZMZ-406/405/409 engines use tramblers with different drive shaft lengths. Installing a short shaft on a long engine will result in the drive not catching on the oil pump, and the engine will not start.

Regular checks and proper ignition installation will extend the life of your ZMZ-402 engine for many years to come. Remember that this system does not require complex electronic equipment for maintenance, but instead requires the owner to understand the principles of operation and accuracy in execution.

What do you do if there's no spark?

1. Check for voltage on the coil. 2. Check the switch (if worth it) or the contacts of the interrupter. 3. Make sure the runner is intact and not pierced on the body. 4. Check the central wire by placing it on the mass (5-7 mm) and spinning the starter.

Frequently Asked Questions (FAQ)

What is the best spark plug gap for ZMZ-402?

For the contact ignition system on the engine ZMZ-402 recommended gap candle is 0.8-0.95 mmIf the gap is larger, the breakdown can be unstable, especially under load, and if it is smaller, the spark will be weak, leading to nagaroprostivo.

Can I use an electronic ignition instead of a contact ignition?

Yes, it's a popular development, and you can install a contactless system (BSZ) from VAZ-2108 or specialized kits for GAZ, which eliminates the need to adjust the gap of contacts and improve spark formation at high revs, but requires replacing the coil and adding a switch.

Why is the ignition coil warming?

The coil warms up if the ignition lock is left on when the engine is not working (current goes through the primary constantly). Also, the cause may be too much current in the circuit (breaker malfunction or lack of additional resistance, if it is provided by the circuit).

How does the octane number affect the angle of advance?

The lower the octane number of the fuel, the higher its tendency to detonate. Therefore, when switching from AI-92 to AI-80, the angle of advance should be reduced (shift the mark to later ignition) to avoid destructive detonation.

Do I need to lubricate the interrupter's fist?

Yes, but moderately. There's a felt fuse on the cam of the distributor, and it needs to be lubricated with 1-2 drops of engine oil every 5,000 to 10,000 kilometers. Excess oil will lead to splashing and contamination of the contacts, and the lack of it will lead to rapid wear and tear of the textolite insert.