ZIL 131 contact ignition system

The engine is equipped with a shielded, sealed battery ignition system, consisting of a B 102-B ignition coil, an R102 ignition distributor, CH307 spark plugs and high-voltage wires in shielding hoses and manifolds, as well as an ignition switch

ZIL-131 contact ignition system

The additional resistance SE102 is connected in series with the coil, which is automatically short-circuited at start-up to compensate for the battery voltage drop associated with the starter being turned on.

The additional resistance is not sealed, and therefore it is attached above the level of the ford.

R102 distributor of ZIL-131

The P102 distributor is sealed, shielded, eight-spark, with a centrifugal ignition timing controller.

For smooth adjustment of the ignition timing depending on the type of fuel used, an octane corrector is used, consisting of two plates, one of which is bolted to the distributor housing, and the second is bolted to the drive housing (on the cylinder block).

By turning the adjusting nuts of the octane corrector, the mutual movement of the plates and, accordingly, the rotation of the distributor body are achieved.

In order to provide access to the high voltage sockets on the cover of the distributor, the cover of the shielding cap is made removable and fastened with three bolts.

To access the breaker, the entire shielding cap is removed, which, in turn, is also fastened with three bolts to the distributor housing.

When disassembling the screen, pay special attention to the safety of the gaskets.

The inputs of the low and high voltage wires from the ignition coil are sealed with rubber rings to seal the fitting shank of the distributor housing, a groove is made on it into which the sealing rubber ring is laid.

The distributor is sealed as it is designed to work underwater (when overcoming a ford).

In order to avoid accelerated burning of the breaker contacts, damage to high-voltage plastic parts and corrosion of internal metal parts under the influence of ozone generated as a result of sparking during the operation of the distributor, its internal cavity is forcibly ventilated; for this, two holes with a conical thread are provided in the distributor housing for connecting fittings of flexible ventilation hoses.

The distributor is ventilated with filtered air.

Distributor operation with muffled ventilation is not allowed.

The centrifugal ignition timing controller has the following characteristic:

Roller revolutions per minute





Advance angle along the distributor shaft in degrees





- At a speed of rotation of the distributor roller below 400 rpm, the characteristic of the regulator is not regulated.

To reduce the level of radio interference from the ignition system, a combined contact carbon with an ohmic resistance from 8000 to 13,000 Ohm is installed in the distributor cap.

The capacitance of the distributor capacitor should be in the range of 0.27-0.35 microfarads.

The ignition coil B102-B is sealed, shielded, attached to the cab shield above the distributor.

The coil has two low voltage terminals, one of which VK is connected through the additional resistance SE102 to the short-circuit terminal of the ignition switch, the second R is used to connect the coil to the distributor.

Spark plugs SNZ07 shielded, sealed, have M14 X 1.25 thread on the screwed part of the body and thread in the upper part of the shield M18X 1 (under the union nut of the hose). Candle set includes:

ZIL-131 Spark Plug

sealing rubber bushing 1, sealing the wire entry into the spark plug, ceramic insulating bushing 2 of the screen and ceramic insert 3 with damping resistance from 1000 to 7000 Ohm built into it.

This resistor is designed to reduce the level of radio interference from the ignition system and reduce burnout of the spark plug electrodes.

The contact of the wire with the electrode of the insert is carried out using the contact device KU-20A or KU-20E.

As shown in the figure, a rubber sealing plug plug is put on the end of the high voltage wire coming out of the shielding hose and then the wire is inserted into the contact device.

The core of the wire, bare at a length of 8 mm, is inserted into the hole of the sleeve, flared in the bottom of the ceramic cup of the contact device, and fluffed so that the contact device is clamped on the wire.

The gap between the electrodes of the candle should be within 0.5-0.6 mm.

The candle is one of the most critical components of the ignition system, since the reliability of the entire system largely depends on its condition.

When carbon deposits form on the plug, current leakage is created, which leads to a decrease in the secondary voltage. The burning of the electrodes causes an increase in the breakdown voltage of the spark gap of the candle.

The breakdown voltage in some cases can even exceed the maximum voltage developed by the ignition system, resulting in misfiring.

If there are interruptions in the ignition, first of all, you need to check the gap between the electrodes and, if necessary, adjust it.

High voltage wires of the PVS-7 brand have two-layer insulation and a core of seven stainless steel wires.

The wires are enclosed in shielding sealed hoses of the RG type with an inner diameter of 8 mm in the area from the candles to the prefabricated manifolds and with an inner diameter of 25 mm from the manifolds to the distributor.

To reduce the length of the high voltage wire from the coil to the distributor, a shielding angle is installed on the distributor screen.

All individual hose connections are sealed with rubber sleeves, and large diameter hose joints are sealed with tapered aluminum rings.

The contact of high voltage wires with the central electrodes of the candles is carried out using contact devices.

The combined ignition and starter switch VK21-E is designed to turn the ignition and starter circuits on and off. It is installed on the front shield of the cab.

The switch has three positions, two of which are fixed. In position 0, everything is off, the key is freely inserted into the lock and removed from it.

Position I - terminal K3 (ignition) is on by turning the key clockwise (see diagram).

Position II enabled terminals K3 (ignition) and CT (starter) by turning the key clockwise. Position II is not fixed, return to position I is carried out by a spring after removing the force from the key.

Care of the ignition system

Care for the ignition coil, distributor and wires.

Low-voltage terminal connectors are designed for wires of the PGVAE brand 1.5 mm² (GOST 9751-61) with a shielding braid.

When assembling the plug connector, the core of the PGVAE wire must be stripped to a length of 17 mm, assembled with the connector parts in such a way that all wires of the core enter the bushing, pull the core to the stop of the wire insulation into the contact bushing, separate the ends of the core and solder them with POS solder -30 or POS-40 to the contact sleeve without the use of acid and without strong heating in order to avoid damage to the insulating sleeve and wire insulation.

The soldering should protrude above the end of the contact sleeve by no more than 0.5 mm and must ensure the tightness of the soldered hole of the contact sleeve.

Plug connector sketch

When filling the ends of the screen, it must not be overstretched; to secure it, the shielding braid of the wire must be placed between the washers of the connector, and the tabs on one of the washers should be bent onto the other washer, then the screen should be fixed to the sleeve of the plug connector with a clamp.

After completing the installation of all wires and the ventilation system, check and ensure that all nuts of the low-voltage terminals and ventilation fittings, as well as the bolted connections of the distributor, are tightened to the stop.

When tightening the tie bolts that secure the screen cover and the screen, do not overtighten them, since the sealing of the joints of the cover with the screen and the screen with the body is structurally reliably ensured by rubber sealing rings when the end metal surfaces come into contact at the sealing points;

Further tightening of the bolts does not improve the tightness, but will only inevitably lead to thread stripping or tearing off of the bolt head; also, when wrapping the low-voltage contacts of the connectors of the high-voltage terminals, they should not be overtightened; sealing in the terminals and connectors is ensured by rubber sealing rings when the nuts are screwed up to the stop.

When filling the plug connectors, it is necessary to monitor the correct connection of the ignition coil leads in accordance with the marking of the terminals (VK and P).

If the installation is carried out with the ignition on, then you need to connect the wires to the VK connector last.

When tightening the nuts of the low-voltage connectors, hold the shield braid by the clamp, preventing it from twisting.

During operation, it is necessary to maintain the breaker contacts in good condition (i.e., keep them clean and adjusted).

It is necessary to monitor the lubrication of rubbing parts; excessive lubrication of the distributor is harmful, as it can lead to rapid wear of the breaker contacts if oil gets on them and to the failure of the distributor.

It is necessary to monitor the cleanliness of the distributor and its parts, especially insulating parts (lid, slider, terminals, etc.).

After each, even partial disassembly of the distributor, it is necessary to ensure its tightness by correctly laying the rubber sealing rings and tightening the fasteners of the shield-to-body connections, the shield-to-screen cover, the nuts of the high-voltage fittings and the low-voltage plug connector to the stop, monitoring the timely replacement of worn rubber sealing rings with new ones (attached to the distributor), as well as tightening the fittings of the ventilation pipes of the air inlet and outlet to the stop, while avoiding tightening the nuts and bolted connections.

It is necessary to monitor the reliability of the connection of high-voltage wires with the terminals of the distributor cover and coil, as well as wires with connector contacts.

It is necessary to monitor the reliability of all connections of the shielding parts on the engine. It is necessary to protect plastic parts from breakage (lids slider and coal in the distributor cap).

You need to make sure that fuel and oil from the engine do not get into the distributor.

It is necessary to maintain the tightness of the entire ignition system, watching the tightening of the union nuts of the high voltage wire hoses, connectors and screen parts.

The ignition coil must be protected from mechanical damage.

For TO-2 you need:

  • 1. Tighten the lubricator cap one turn to supply lubricant to the distributor roller.
  • 2. Wipe the plastic distributor cap with a clean, dry or gasoline-soaked cloth.
  • 3. Inspect the cam and, if dirty, wipe it with a cloth soaked in gasoline.
  • 4. Lubricate the chopper lever axis with one drop of the oil used to lubricate the engine, two or three drops of the same lubricant with the cam bushing (having previously removed the slider and the oil seal under it), the cam filter is impregnated with a special lubricant, and it is not required to add it.
  • 5. After lubrication, check that the lever on the axle is not stuck; to do this, press the lever with your fingers and release it. The released lever should quickly return (under the action of a spring) and the contacts should close with a click.

If the contacts do not close or the lever moves slowly, it is necessary to eliminate the jam in the conditions of the repair shop and adjust the tension of the breaker spring within 500-650 g by removing the lever and carefully bending the spring in one direction or another.

  • 6. Check the cleanliness of the breaker contacts: if necessary, remove dirt and oil from the contacts by wiping the contacts with suede soaked in clean gasoline, then pulling the lever, let the gasoline evaporate and wipe the contacts with clean, dry suede.

Instead of suede, you can use any material that does not leave fibers on the contacts, and instead of gasoline, you can use alcohol to wipe the contacts.

  • 7. Check the condition of the working surface of the contacts, and only in case of a large transfer of metal from one contact to another, and if the formed tubercle on the contact makes it impossible to measure the gap between the contacts, clean them.

Clean the contacts with a thin (about 1 mm) abrasive plate or fine glass sandpaper. It is forbidden to use sandpaper, a needle file and other means other than those indicated above to clean the contacts.

If any interruptions occur in the operation of the engine, in no case should the contacts of the breaker be stripped unless it has been previously established that the interruptions are caused by the breaker.

When stripping the contacts, remove the bump on one of them. Contacts should not be cleaned until completely eliminated (deepening) crater on another contact. After stripping, rinse the contacts, dry them as described above, and adjust the gap between them.

When cleaning contacts, it is necessary to cut their planes, maintaining the necessary parallelism so that during operation the contacts touch each other with the entire plane (without a gap between them)

Each time the distributor is removed from the vehicle, the ignition setting must be checked.

  • 8. Check and in; if necessary, adjust the gap between the contacts. The gap between the contacts should be within 0.3-0.4 mm.

You need to adjust the gap in the following order:

  • a) turn the distributor roller until the cam protrusion presses the lever pad so that the largest gap is established between the contacts; loosen the screw securing the fixed contact post and turn the eccentric (located at the fork of the post) with a screwdriver so that a feeler gauge 0.4 mm thick fits tightly into the gap between the contacts c) tighten the screw fixing the fixed contact post and check the gap again with a feeler gauge; the dipstick must be clean; it should be wiped with gasoline before use.
  • 9. If necessary (in case of complete wear of the contacts), it is allowed to replace the breaker lever and the contact stand once during the entire warranty period of the distributor, the set of which is included in the spare parts.

When replacing the lever, use the key supplied with the distributor.

10. Check the condition of the rubber sealing rings, replace them if necessary.

For the entire warranty period, it is allowed to replace the sealing rings twice, two sets of which are applied to the car.

Installing the high voltage wire into the socket of the ignition coil cover. Proper installation of the high voltage wire in the socket of the ignition coil cover is essential for the operation of the ignition system.

In the case of prolonged operation of the engine with the wire not fully installed in the coil socket, sparking occurs between the tip of the wire and the high-voltage terminal embedded in the plastic cover.

As a result, the plastic in the socket may burn out, the electrical strength of the plastic may decrease, and even the ignition coil may not work.

The following is the procedure for checking the installation of the high voltage wire in the socket of the ignition coil cover:

  • 1. Measure the length of the wire from the end of the lug to the end of the hose union nut, pressed towards the wire lug. This length should be 70-75 mm.
  • 2. Inspect the end of the wire with a ferrule. Remove any solder build-up on the tip that prevents the tip from being inserted into the socket.
  • 3. Check the presence of two sealing rubber rings on the wire, insert the wire all the way into the socket of the ignition coil cover, tighten the fitting and the union nut of the shielding hose.

If the length of the wire from the end of the lug to the end of the hose union nut, pressed towards the wire lug, is less than 70 mm, the wire must be reinstalled. for this you need:

1. Remove the cover of the distributor screen, remove the wire from the central socket of the distributor cover and, having unscrewed the fitting and the union nut of the hose, pull the wire out of the distributor screen.

O-ring position on wire before installation

  • 2. Move the sealing rubber rings on the wire, carefully pull the wire in the shielding hose towards the outlet to the ignition coil and install the first rubber ring 2 from the wire end at a distance of 50 mm.
  • 3. Insert wire 1 into the socket of the ignition coil. The wire must go into the socket until it stops: the wire end must snap into the groove of the high-voltage coil terminal.

While holding the wire with your hand, insert fitting 3 and tighten. Then move the second sealing ring 4 to the fitting, tighten the union nut 5.

  • 4. Connect the other end of the shielding hose 6 to the high-voltage output of the distributor shield and insert the wire into the central socket of the distributor cap until it stops.
  • 5. Install the shield cover, tighten the bolts and union nuts of the shield hose.

Caring for spark plugs. When repeating TO-1, the candles must be turned out and their condition checked.

1. Check the gap between the electrodes with a wire probe. The use of flat probes is unacceptable, since with a flat probe, the measurement gives an incorrect result (the measured gap is less than the actual one).

If the spark gap is greater than 0.6 mm, it must be adjusted by bending the ground electrode only.

When bending the central electrode, the skirt of the spark plug insulator is destroyed.

It is advisable to slightly file the electrodes before adjusting the gap needle file to obtain edges, since in the presence of blunt edges, the voltage required to breakdown the spark gap increases significantly.

The gap must be adjusted within 0.5-0.6 mm. When operating in winter, it is advisable to set a gap of 0.5 mm.

  • 2. If the candle insulator is covered with soot and soot, then the candle must be cleaned on a special candle cleaner.
  • 3. Removable parts of the candle (ceramic insulating sleeve of the screen and insert) must be wiped with a clean rag soaked in gasoline.
  • 4. If the rubber sealing sleeve is severely deformed or has lost elasticity, a new sleeve should be installed, which is included in the spare parts (it is allowed to replace the sleeve once during the warranty period of the spark plug).
  • 5. When screwing in and out of the candle, use only the candle wrench.

If, when unscrewing the union nut of the hose from the candle, when the engine is warm, the candle itself is turned out of the head, then you should not try to hold it with pliers against the screen.

It is better to unscrew the candle and then, holding it by the hexagon of the body with a candle wrench, unscrew the nut.

The tightening torque of the union nut of the hose should be no more than 2.5 kgm, the tightening torque of the candle should be no more than 3.5 kgm.

  • 6. When installing a spark plug on the engine, it is necessary to check the presence and condition of the sealing ring.

During normal operation of the spark plugs on the engine, the insulator skirt should be brown. The light yellow (almost white) color of the insulator indicates a significant overheating of the candle.

The thermal characteristics of the spark plug SNZ07 fully correspond to the conditions of operation of this spark plug on the engine in all modes of Normal operation of the latter.

In particular, the spark plug does not create glow ignition when the engine is running for a long time at wide open throttle.

The phenomenon of the so-called "run-out" of the engine, that is, the operation of the engine after the ignition is turned off, often taken for glow ignition, usually has nothing to do with abnormal overheating of the spark plugs and is completely eliminated if the heated engine is allowed to run for a short time before the ignition is turned off. idling.

Significant "run-out" indicates the presence of a large amount of carbon in the head of the block.

Prolonged idling with a low crankshaft speed and prolonged vehicle movement at low speed in fifth gear should not be allowed, since in this case the skirt of the spark plug insulator becomes covered with soot, interruptions in the operation of the spark plug occur (during subsequent starts of a cold engine ) and the contaminated surface of the insulator is moistened with fuel.

With smoked candles (when the soot is dry on the skirts of the insulator), starting a cold engine is difficult; when the surface of the insulator is moistened with fuel, it is impossible to start the engine.

Proper operation of the spark plugs is highly dependent on the thermal state of the engine. At low air temperatures, the engine must be insulated (use an insulating hood, close the radiator blinds).

After starting a cold engine, you should not immediately move the car from a place, as if the candles are not heated enough, interruptions in their operation may occur.

When driving after a long stop, long accelerations should be used before shifting to higher gears.

Spark plugs can also work intermittently in cases where the rules for starting the engine are not observed or when, while driving, they allow the working mixture to be enriched with fuel by covering the carburetor air damper.