If installation of the moment of ignition was broken, we check and if necessary we regulate the ignition moment (see Check of installation of the moment of ignition).

For fine tuning of a corner of an advancing of ignition under specific composition of fuel on the case of the distributor of ignition the scale an octane proofreader is put.

We mark with a chisel on inflow of the block the middle of a scale – zero situation an octane proofreader.

At the engine which is warmed up up to the working temperature, moving on the IV transfer with a constant speed of 50 km/h, sharply we press a pedal of "gas". If at the same time the detonation (on a sound it is similar to a ring of valves) appears for a short time, 1–3 with – a moment of ignition is chosen correctly. At a long detonation a corner of an advancing of ignition we reduce an octane proofreader by 1/2 divisions of a scale, and at its absence – we increase. We carry out a repeated inspection in the movement and if necessary we continue adjustment.