1.What is the heat rating of a spark plug?

Spark plug heat rating is a index represent an ability of balance heat absorption and heat radiation, usually a number instead of, and within the type of spark plug. Spark plug heat rating has no meaning in fact, only a relative value.

Hot type

Heat radiation is slow.

There is a greater surface area exposed to the hot combustion gases. Heat transfer to the engine head is slower.

Cold type

Heat radiation is quick..

Less surface area exposed to the hot combustion gases. Heat transfer to the engine head is quicker.


2.How can you do spark plug heat rating matching?

The spark plug heat rating should match the engine.If we can’t do it well,when the spark plug is overheating,the electrode will melt,when the spark plug is supercooling,the carbon deposit will appear.


3.The conditions of inproper installation

Torque too big, thread cracked, thread broken, ceramic cracks, wrench cracked, torque is too small, the gasket out of shape, electrode overheat, rupture.


4.Specially designed spark plug

(1)V-groove center electrode spark plug

Center electrode tip make a v incision ,can more accurately produce SparksThe flame core is generated near the perimeter of the electrodes and grows.Ignitability is improved because the electrodes are interfering less with the growth of the flame core.

(2)Iridium spark plug

Iridium is used at the tip of the center electrode.It can produce spark easily and has excellent ignitability. Better performance is achieved with improved starting,acceleration,and idling stability,as well as fuel-efficiency.

(3)Multi ground electrode spark plug

The design of multi-electrode can be dispersed electrode consumption, ensuring durability. Multiple electrode has a good effect on discharge characteristics, extending the life of spark plugs.


5.Spark Plug Frequently Asked Questions

1.Carbon fouling

Appearance:The insulator foot section and electrode section are covered by dried,soft black carbon.

Result:Poor starting,misfiring,acceleration defect.

Cause:1incorrect choking(overly rich air-fuel mixture)

          (2 Repeated short-distance driving(driving with the engine cool)

          (3Bad quality fuel,combustion is not normal

          (4 Spark plug heat range too high.


Appearance:The center electrode or ground electrode is melted or scorched.There are spots on the insulator nose section and deposits of aluminum or other metal powder.

Result:Power loss due to engine damage.

Cause:Due to overheating,pre-ignition is a phenomenon in which combustion occurs before ignition.The plug heat range is too low,the injection timing is too advanced,etc.


3.Appearance:Insulator cracked.

Result: Insulation defect,causes poor idling and misfiring during acceleration.

Cause:Spark plug removed/installed incorrectly(spark plug turned too far with spark plug wrench,excess tightening torque,or other inappropriate work).