seattlesetr.blogg.se - Ngk heat range chart

Reduced compression and oil usage due to worn piston rings/cylinder wallsĬarbon fouling occurs when the spark plug firing end does not reach the self-cleaning temperature of approximately 450☌ (842☏).

Continuous low-speed driving and/or short trips.

The heat range must be carefully selected for proper spark plug thermal performance. If the heat range is not optimal, then serious trouble can be the result. The optimal firing end temperature is approximately 500☌ (932☏) to 800☌ (1472☏). The two most common causes of spark plug problems are carbon fouling ( 800☌). A colder spark plug functions in an opposite manner. The insulator nose of a hotter spark plug also has a greater surface area that is exposed to more of the ignited gases and is easily heated to higher temperatures. Therefore, the path for the dissipation of heat from the insulator nose to the cylinder head is longer and the firing end stays hotter. The insulator nose of a hotter spark plug has a longer distance between the firing tip of the insulator and the point where insulator meets the metal shell. A hot-type spark plug has a longer insulator nose. The major structural difference affecting the heat rating is the length of the insulator nose.

Relative position of the insulator tip to the end of the shell (projection).

Structure of the center electrode such as a copper core, etc.

Thermal conductivity of the insulator, center electrode, etc.

Surface area and/or length of the insulator nose.Some basic structural factors affecting the heat range of a spark plug are: Heat rating and heat flow path of NGK Spark Plugs The heat rating of each NGK spark plug is indicated by a number lower numbers indicate a hotter type, higher numbers indicate a colder type. The heat range of a spark plug is the range in which the plug works well thermally. The spark plug heat range has no relationship to the electrical energy transferred through the spark plug. This is called “thermal performance,” and is determined by the heat range selected. The spark plug firing end temperature must be kept low enough to prevent pre-ignition, but high enough to prevent fouling. A sufficient amount of voltage must be supplied by the ignition system to spark across the spark plug gap. Spark plugs must provide a path and a location for electrical energy from the ignition coil to create a spark used to ignite the air-fuel mixture. The primary function of the spark plug is to ignite the air-fuel mixture within the combustion chamber under any operating condition. The experienced tuner can use spark plugs to find the root cause of problems, determine air-fuel ratios and increase vehicle performance. The spark plug displays the condition inside the combustion chambers of the engine. Spark plugs are a “window” into the engine and can be a valuable diagnostic tool. This basic guide is designed to assist the technician, hobbyist or race technician in understanding, using and troubleshooting spark plugs. Spark plugs have been around as long as internal combustion engines have and are often a misunderstood component.