How to read NGK spark plug codes

[Blaner]

I have noticed a number of questions lately regarding spark plugs, different codes on the plugs mean different things.

Here is a nice chart which decodes the codes !

So if we take the standard blaster plug which is B8ES, we can interpret it as : B = Thread Diameter : 14mm; 8 = Heat Range: Medium; E= Thread Reach: 19mm; S= Firing End Construction: Standard super copper core center electrode.

If you have a BR8ES, the R = Construction features: Resistor type, and unless you have a radio that you dont want to cause interference with, the R is not necessary on a bike

Some guys use the B8EG, and G = Firing End Construction: Fine wire nickel center electrode.

 

[sicivicdude]

Good post man!

It should be noted if you're trying to find a particular plug (cross referencing) to a different brand, NGK uses a reverse heat range number than most any other brand (autolite, ND, bosch, AC delco, champion)

NGK heat ranges drop as the plug gets "hotter". Most every other manufacturer's part number's work with common sense and the higher numbers are hotter and the lower numbers are colder.... If you are straight cross referencing, number for number you'll be OK as most manufacturers have a straight number to number cross.... If you're trying to get a hotter or colder plug... you'll need to know this!

 

[Blaner]

that is correct Sic, NGK work backwards for some reason!

 

[Prime]

Sweet post! I can see it being very helpful. Sticky?

 

[Braaaptor]

Sticky!

Great find. I've been looking for one of these to keep around the shop to explain to people how NGK plugs are set up. Now we've got it!

 

[slickerthanyou]

Nice post there Blaner! I'll contribute what I have too, same info but comparing the two plugs. EG and ES! If you notice the length of the center electrode is .55in longer, even though they are the same "heat range"(8)!

 

[Blaner]

there we go, thanks Slick, i hope this helps clear up some confusion!