หัวเทียนมาตรฐาน JR8C 5139

Webike has all NGK plugs in stock! .
* The item may be temporarily out of stock due to manufacturer shortages, etc
Stable ignition performance and combustion efficiency at a reasonable price.It brings out the true performance of the engine.

[Features of Register plug]
A ceramic resistor is built in to suppress the ignition noise generated at the time of spark.
・The built-in ceramic resistor suppresses the ignition noise generated by the spark.
・Prevents radio noise in car radios, mobile hams, and car telephones.It also prevents the engine control computer from malfunctioning due to noise.



[What is a multi-pole plug?]
A multi-polar plug is a plug in which the outer electrode (grounding electrode) has a multi-polar specification (multiple electrodes).
The purpose of using a multi-pole outer electrode is to ensure durability by dispersing the electrode wear.The multi-pole plugs also have the effect of improving the discharge characteristics (lowering the required voltage).
*Many of the plugs of this type have a structure in which the spark flies along the surface of the insulator in the ignition area, and include intermittent discharge plugs, plugs with an auxiliary spark gap, and semi-creepage plugs.

■How to select a plug


*The effect varies depending on the vehicle.

[About the shape of the plug terminal]
●Select a terminal shape that matches the engine and plug cord installation side.
There are three types of plug terminals: integrated type, separate type, screw type, and punch-and-caulk type.
Mainly, "integral type" and "punch caulking type" are used for four-wheeled vehicles and "screw type" for two-wheeled vehicles, and "separate type" is available for plugs used for both four-wheeled and two-wheeled vehicles.
In addition, the terminal part of the "separate type" can be removed, but the terminal part of the "integrated type" and "punch-and-caulk type" cannot be removed.If you try to remove it forcibly, the terminal part may be broken.
In case of using the "separate type" as the "screw type", remove the terminal nut.
When using the product with the terminal nut attached, make sure that it is not loose, and if it is loose, tighten it lightly with pliers or the like.

[Features of NGK plug]

- This is a super "wide range" plug -

The center electrode , The center electrode is a "copper cored" construction with copper sealed to near the tip to allow a large amount of heat to escape quickly. The result is an ultra "wide range" plug that is resistant to burning and smoldering.

Comparing the thermal characteristics of plugs with copper cores and plugs without copper cores, the plugs with copper cores have superior thermal characteristics and fouling resistance, and a wider thermal range.

■ Heat value of the plug

- High alumina porcelain from New Ceramics is used as the insulator -

- Excellent insulation at high temperature and reliable sparking. ・Excellent heat conductivity and prevents seizure. ・High thermal shock resistance (rapid heating and cooling) and excellent mechanical strength.

- Strong and airtight in construction -

Because the insulator and the main metal fittings are joined by special powder, it is excellent in airtightness and strong in structure.

Special Nickel alloy electrodes are used for superior durability.

- Corrugations in the insulator ensure good insulation and prevent flashover -

During sparking, a high voltage is constantly applied between the terminal and the main unit bracket. High voltages try to leak along the surface of the insulator and flashover is more likely to occur if the required voltage between the spark gaps is high. In order to prevent flashover, insulator corrugations (folds) are provided to increase the insulator surface distance between the terminal and the main fittings to ensure insulation and prevent flashover.

What is a flashover...

It is a spark between the terminal and the main unit fitting as shown in the image.

■ Flashover

■The advantages of the plug