Setting the ignition timing (VAZ-2121)

To check the ignition timing, there are three marks 1, 2 and 3 (Fig. 7-19) on the timing mechanism drive cover and mark 4 on the crankshaft pulley, corresponding to the TDC of the piston in the first and fourth cylinders when aligned with mark 3 on the cover.



You can check and set the ignition timing using a stroboscope in the following order:

• set the octane corrector eccentric of the ignition distributor to the zero position (if the engine is equipped with a P-125 V ignition distributor),
• connect the "+" clamp of the strobe switch to the "+B" terminal of the ignition coil, and the "ground" clamp to the "-" terminal of the battery;
• insert an adapter for connecting a strobe lamp between the spark plug wire of the first cylinder and the spark plug and mark mark 4 on the crankshaft pulley with chalk for greater visibility;
• start the engine, directing the flashing beam of the strobe light to the mark on the pulley; if the ignition timing is set correctly, when the engine is idling, the visible mark 4 on the pulley should be opposite mark 2 on the timing mechanism cover.

To adjust the ignition timing, stop the engine, loosen the distributor mounting nut and turn it to the required angle. To increase the ignition timing, turn the distributor housing counterclockwise, and to decrease it, turn it clockwise. Then check the ignition timing again.



If you have a diagnostic stand with an oscilloscope, you can also easily check the ignition timing using it, following the instructions for the stand.

Install the ignition distributor removed from the engine in place in the following order:

• remove the distributor cap, check and, if necessary, adjust the gap between the breaker contacts;
• turn the crankshaft until the compression stroke in the first cylinder begins, and then, continuing to turn the crankshaft, align mark 4 with mark 2;
• turn the rotor to a position where its outer contact is directed towards the contact of the first cylinder on the distributor cap;
• holding the distributor shaft from turning, insert it into the socket on the cylinder block so that the centerline passing through the spring clips is approximately parallel to the centerline of the engine;
• fasten the distributor to the cylinder block, install the cover, connect the wires, check and adjust the ignition timing.

The text is on the website: VAZbook.ru