Spark Plug Clearance

Despite the simplicity of the structure of the spark plugs, they need to work and handle appropriately. They need to be correctly cleaned, adequately selected and changed. However, even new options can sometimes cause problems. the car can work unevenly, sometimes there are jerks (jolts) when it picks up speed, as well as light detonation. Many immediately begin to look for the cause in the ignition system. of course, because the candles are new! However, the gap between the electrodes may be to blame, it is enough to fix it, and the engine will “sing.”

Spark plug clearance

This is the distance between the upper and lower electrodes, which is necessary for optimal operation and ignition of the fuel mixture. If this distance is different from the recommended standards, the engine will not work smoothly, either twitching is possible, or detonation is similar to the “build-up” of your unit.
In simple words, if the gap differs from the norm, it is set so from the factory or by the seller, then you can shovel at least half of the motor, and the reason is not found. Especially strongly manifested on carburetor systems. BUT for a start, I propose to start with the device and the principle of operation.

How does the ignition in the cylinder

If we talk about candles, then this is the last link in the ignition system, which is in direct contact with the air-fuel mixture. It is this element that ignites it, and does it either. effectively and as laid down in the technical regulations, or inefficiently for several reasons (by the way, wear is often the cause).
After the fuel mixture (gasoline and air) have been fed into the cylinders, the piston starts to go up and compress it, thereby increasing pressure.
In the peak or as it is called in the “top point”, the computer gives the order and ignition of this composition occur. And the spark plug ignites it. a spark runs between the electrodes, which is the catalyst.
However, the ignition may not occur; I do not take options now with a malfunction of the ignition system, just put up. not the right gap. Thus, there can appear “transmissions” (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 winter morning). But why is this happening?

The effect of proper clearance on motor performance

Clearance is a significant parameter. It can be either big or too small.

Small clearance

If small values ​​are set between the electrodes, they will show gaps in the ignition system. The thing is that the spark that forms between the electrodes as close as possible to each other is not enough to ignite the fuel mixture. A spark though strong, but not enough. That is why many cars while driving will twitch and do not develop sufficient speed. On the carburetors can fill candles that will only give problems. The gap must be increased!
A small gap is how much? If we talk about the size, it is approximately from 0.1 to 0.4 mm. Be sure to check the candles after purchase, practical recommendations will give a little lower, but for now, let’s talk about a long distance.

Large clearance

You know, yet many manufacturers pre-expose the standard distance between the electrodes. But over time, it can increase.
It’s all about the wear of the candle, which manifests itself with a tremendous run. this is natural. After all, the electrodes are made of metal, which under the influence of temperature and constant electrical discharges begins to fade slowly. Suffer as the top similar to the letter “G”, and the bottom. Upper becomes thin, instead of a rectangular shape, it begins to round out because the sides are burned. The bottom sags down.
Because of this distance, the spark that passes between the pins weakens. And significantly! It may also not be enough to ignite the fuel.
Often, because of this, an insulator of the lower contact is pierced, the whole point is that the spark tries to find the shortest path between the electrodes.
In winter, there is a high probability that the machine does not start.
One more important aspect, on the removed electrodes more often a deposit in the form of a deposit can appear, a spark so “suffers” from a long distance, so also a raid! She generally can not pass. Therefore, it is important after a certain mileage, with our fuel it may already be 15,000 km, unscrew the candles if necessary to change them, or clean them.
Long distance. from 1.3 mm and above.

Normal clearance, what you need to focus on

We have definite limits. Lower from 0.4 mm (and all that is lower), upper from 1.3 mm (and all that is higher). So what is considered the normal size for your car?
You know, and there are differences here, they are connected primarily with the car ignition system, it can be divided into three types:

  1.  With the carburetor type, with the distributor. an average clearance of from 0.5 to 0.6 mm
  2.  With the 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. it’s about the ignition system and the electrical circuit. The lowest voltage at the carburetor, respectively, the spark will be weaker, and therefore the gap should be smaller. But the most powerful energy system of the injector, so here the gap increases, 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 begin with, just unscrew the spark plugs, then look at the damage, if not, then you can clean it up first, then check the clearance.
Probes look like metal curved letters “G”, with different sizes, just 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 draw closer to each other, you can just tap the screwdriver. If it is too close. then push it apart, again checks with a probe.

Modern technologies

What I want to say in conclusion, many will think “yes, throw it out”, why should I bother with some distance between the electrodes! The guys are very wrong thoughts.
First of all, 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 resource, there is no likelihood that the insulator will penetrate (with an increased distance).
It should be noted that some companies, on the contrary, increase the number of contacts (electrodes), amplify the coils and the ignition system, all for the mixture to be ignited better.
Also now there are more modern technologies that I think will soon be replaced. such as plasma candles.

They have no electrodes at all, and the fuel ignites a plasma beam that is generated from electricity. As they say, they were already undergoing tests, and they say that the efficiency of combustion of the fuel mixture increases, and this is a little more power, a little more economy and environmental friendliness.
And on this I have everything, read our AUTOBLOG, it will be interesting.