To check the ignition timing, there are three marks 1,2 and 3 (pic. 7-18) on the cover of the gas distribution mechanism and mark 4 on the crankshaft pulley, corresponding to V.M.T. piston in the first and fourth cylinders when it coincides with mark 1 on the cover.
Pic. 7-18. Tags for setting the ignition timing:
1 - ignition advance mark by 10°; 2 - ignition advance mark by 5°; 3 - ignition advance mark by 0°; 4 - mark w.m.t. on the crankshaft pulley.
You can check and set the ignition timing using a stroboscope, proceeding in the following order:
- connect clamp «plus» stroboscope with output «plus» battery clamp «masses» - with conclusion «minus» battery, and connect the stroboscope sensor clamp to the high voltage wire of the 1st cylinder. Mark with chalk mark 4 on the crankshaft pulley for better visibility;
- start the engine and point the flashing strobe light at the mark on the pulley; if the ignition timing is set correctly, then with the engine idling, the position of mark 4 on the pulley must correspond to the data in Appendix 3.
To adjust the ignition timing, stop the engine, loosen the nut of the ignition distribution sensor and turn it to the required angle. To increase the ignition timing, the distributor sensor housing should be turned counterclockwise, and to decrease it, clockwise. Then check the ignition timing again.
For the convenience of adjusting the ignition timing, there are divisions and signs on the flange of the ignition distributor «+» and «-». One division on the flange corresponds to eight degrees of rotation of the crankshaft.
If there is a diagnostic stand with an oscilloscope, then it can also be used to easily check the ignition timing setting, guided by the stand's operating instructions.
Install the ignition distributor removed from the engine in the following order:
- turn the crankshaft to the beginning of the compression stroke in the first cylinder, and then, continuing to turn the crankshaft, align mark 4 with mark 3;
- remove the cover from the ignition distributor sensor and turn the rotor in such a position that its outer contact will be directed towards the contact of the first cylinder on the distributor sensor cover;
- while holding the distributor shaft from turning, insert it into the socket on the cylinder block so that the center line passing through the spring latches is approximately parallel to the engine center line;
- fix the distributor sensor on the cylinder block, install the cover, connect the wires, check and adjust the ignition timing.