Which spark plug is better hotter or colder?

When making spark plug heat range changes, it is better to err on the side of too cold a plug. Running too cold a plug can only cause it to foul out, whereas running too hot a plug can cause severe engine damage.

Do hotter spark plugs make a difference?

A “hot” spark plug has a longer insulator that prevents heat transfer into the water jackets. It keeps more heat in the tip of the spark plug, which helps burn off combustion chamber deposits. But if there’s too much retained heat, the engine will experience preignition.

What do the numbers mean on a NGK spark plug?

heat rating
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.

Does a hotter spark plug burn more fuel?

short answer NO, As i have come to understand it a heat range on a spark plug is its ability to TRANSFER heat away from the plug and to the head so a hotter plug will transfer more heat a colder plug will transfer less heat it has nothing to do with you A/F ratio.

Why does spark plug gap increase?

Registered. the gap change is due to abrasion and metal fatigue. the arcing spark constantly wears on the gap, dirt and contaminants also speed this up.

How do I choose a hotter spark plug?

The higher the number, the hotter the plug. The lower the number, the colder the plug. Starting with part # 24 (heat range 4), if you want a colder plug you would use part # 23 (heat range 3), for a hotter plug you would use part # 25 (heat range 5).

Will a hotter spark plug help with running rich?

Yup, running a hotter plug would not lean out the motor, or change the air/fuel mixture at all. Introduction: The spark plug’s location exposes it to extreme temperature variations, chemicals, fuels and oils.

How to find a colder or hotter NGK plug?

For NGK Racing Plugs, the heat range is located AFTER the hyphen. Example: R5671A-10 has a heat range of 10. A colder plug would be # R5671A-11 (heat range 11), a hotter plug would be # R5671A-9 (heat range 9). Some NGK Racing Plugs are also available in half heat ranges.

What does NGK stand for in spark plugs?

NGK indicates the heat range in the middle of the plug number. For example, BCPR6ES-11 has a heat range of 6. (The number after the “-“ is the gap.) NGK plugs are colder the higher the number, hotter the lower the number.

Which is hotter a NGK br9es or a br8es?

On NGK spark plugs, the lower the number the hotter the plug (higher numbers are colder). Thus, your NGK BR9ES is colder than a BR8ES. There are spark plug brands where the numbering system is reversed and the lower numbers are cold and higher numbers are hot, but not that many motocross racers use these plug brands (Champion, Autolite and Bosch).