Stihl 180 What Ignition Gap

Despite the simplicity of the structure of the spark plugs, they need to work and handle correctly. They need to be cleaned correctly, correctly selected and changed. However, even new options can sometimes cause problems. the machine can run unevenly, sometimes there are jerks (jerks) when picking up speed, as well as light knocking. Many immediately begin to look for a cause in the ignition system. of course, after all, the candles are new! However, the reason may be the gap between the electrodes, it is enough to correct it and the engine will simply "sing"

Stihl 180 What Ignition Gap


To get started, a small definition.

Spark plug clearance. this is the distance between the upper and lower electrodes, it is necessary for optimal operation and ignition of the fuel mixture. If this distance differs from the recommended norms, the engine will not work smoothly, either twitching or detonation similar to the “tripling” of your unit are possible.

In simple words, if the gap is different from the norm, set so from the factory or the seller, then you can shovel at least half of the motor, but you can not find the reason. It is especially pronounced on carburetor systems. BUT to start, I propose to start with the device and the principle of operation.

How cylinder ignition works

If we talk about candles, then this is like the last link in the ignition system, which is directly in contact with the air-fuel mixture. It is this element that sets it on fire, and does it either. efficiently and as laid down in the technical regulations, or ineffective for a number of reasons (by the way, wear is often the fault).

After the fuel mixture (gasoline and air) was fed into the cylinders, the piston starts to go up and compress it, thereby pumping pressure.

At peak or as it is commonly called at the “upper point”, the ECU gives an order and this structure ignites. over, his spark plug ignites. a spark runs between the electrodes, which is the catalyst.

However, ignition may not occur, I am not taking options with a malfunction of the ignition system now, I just set it to the wrong clearance. Thus, “transmission” may occur (that is, not ignition of the fuel mixture), which will cause your engine to work with low efficiency, and sometimes it will not start at all (for example, in the morning in winter). But why is this happening.

The effect of proper clearance on motor performance

Clearance is a really important parameter. It can be either large or too small.

Small clearance

If small values ​​are set between the electrodes, they will exhibit gaps in the ignition system. The thing is that the spark that forms between the electrodes that are as close as possible to each other is not enough to ignite the fuel mixture. The spark, although strong, is insufficient. That is why many cars when moving will actually twitch and not develop sufficient speed. On carburetors it can fill candles, which only gives problems. it will generally be troit. The clearance needs to be increased!

Video: Stihl 180 What Ignition Gap

Small clearance is how much? If we talk about the size, then this is from about 0.1 to 0.4 mm. Be sure to check the candles after the purchase, I will give sensible recommendations a little lower, but for now we’ll talk about a long distance.

Large clearance

You know, yet many manufacturers set the normal distance between the electrodes in advance. But over time, it itself can increase.

It’s all about the wear of the candle, which manifests itself with a high mileage. this is natural. After all, the electrodes are made of metal, which, under the influence of temperature and constant electric discharges, begins to slowly burn out. Suffers as the top similar to the letter "G", and the bottom. The upper one becomes thin, instead of a rectangular shape, it begins to round out, because the sides burn. The bottom just sags down.

Due to this distance, the spark that passes between the contacts weakens. And significantly! It may also not be enough to ignite the fuel.

Often, because of this, the lower contact insulator breaks through, the whole thing is that the spark tries to find the shortest path between the electrodes.

In winter, there is a high probability that the car simply does not start.

Another important aspect, deposits can often appear on remote electrodes in the form of soot, a spark so “suffers” from a long distance, so does a plaque! She may not pass at all. Therefore, it is important after a certain mileage, with our fuel it can already be 15,000 km, unscrew the candles if necessary, change them, or clean.

Large distance. from 1.3 mm and above.

Normal clearance to focus on

We have very specific limits. Lower from 0.4 mm (and everything below), upper from 1.3 mm (and everything above). So what is considered the normal size for your car.

You know, and there are differences, they are primarily associated with the ignition system of the car, you can conditionally divide it into three types:

1) For carburetor type, with distributor. normal clearance from 0.5 to 0.6 mm

2) For carburetor type, with electronic ignition. 0.7. 0.8 mm

3) Injector. 1. 1.3 mm

Why such difference? you ask. The answer is simple. the matter is in the ignition system and the electrical circuit. The carburetor has the lowest voltage, so the spark will be weaker, and therefore the clearance should be less. But the injector has the strongest energy system, so here the gap is increased, the normal is considered to be from 1 mm, and on many foreign cars it is 1.1 mm.

How to check and how to set it

The process is not as complicated as it seems at first glance. To get started, simply unscrew the spark plugs, then look at the damage, if there are none, then you can clean it first, then check the clearance.

The probes are similar to the metal curved letters “G”, with different sizes, we simply substitute them between the electrodes and determine the gap with an accuracy of 97%. If it is larger, for example, on the injector than 1.1 mm, then the contacts are brought closer to each other, you can simply tap the handle of a screwdriver. If it is too close, then we move it apart, again it checks with a probe.

Check out my clearance video.

Modern technologies

What I want to say in conclusion, many will think “come on,” why should I bother with any distance between the electrodes! The guys are very wrong thoughts.

At first, you can save on fuel, studies show up to 5. 7%

Secondly, smooth engine operation is the key to driving safety.

Third, the correct gap between the candles increases their life; there is no likelihood that the insulator will break through (with an increased distance).

I would like to note that some companies, on the contrary, increase the number of contacts (electrodes), strengthen coils and the ignition system, all in order to make the mixture ignite better.

Also now there are more modern technologies that I think will soon come to replace. such as plasma candles.

They don’t have any electrodes at all, and the fuel ignites a plasma beam, which is formed from electricity. As they say, they have already tested and they are making tests and they say that the efficiency of the fuel mixture is increasing, which is a little more power, a little more economy and environmental friendliness of the engine.

And that’s it for me, read our AUTOBlog, it will be interesting.

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