Ngk Spark Plug Code Breakdown

[psi]

Please note, This is not my work! I have no control over its accuarcy. But i thinks its good.

Some new plugs may not be on here.. but it should get you pointed in the right direction..

*some fields are optional & others have multiple characters:

Lets do a breakdown of what the codes on an NGK sparkplug mean:

This is a typical spark-plug code: BCPR6ES-11

Now we can break it down..

The feild breakdown is like this.

Feild 1 - 'B'

Feild 2 - 'CPR'

Feild 3 - '6'

Feild 4 - 'E'

Feild 5 - 'S'

Feild 6 - '11'

Feild 1: Thread diameter;

A=18mm

B=14mm

C=10mm

D=12mm

Feild 2: Construction;

C=hex size 5/8

K=hex size 5/8 with projected tip (ISO)

M=compact size

P=protected insulator

R=resistor

SD=surfacedischarge for rotary engines

U=semi-surface discharge

Z=inductive suppressor

Feild 3: Heat Range;

2=Hot ~ 10=cold

Feild 4: Thread reach;

E=19mm

F=tapered

H=12.7mm(1.5")

L=11.2mm(7/16")

Feild 5: Firing end;

A,B=Special design

C=Special ground electode

G=racing

GV=racing use V type

H=half thread

K=2 ground electrodes

L=half heat range

LM=lawn mower

M=2 ground electodes for rotary

N= Special ground electrode

P=platinum tip

Q=4 ground electrodes

R=delta ground electode

S=standard 2.6mm ceter electrode

T=3 ground electrode

V=fine wire centre electrode gold palladium

VX=platinum tip (high performance)

w=tungsten electrode

X=booster gap

Y=V-groove center electrode

Feild 6 Numbers after the dash;

8=0.8mm plug gap

9=0.9mm gap

10=1.0mm gap

11=1.1mm gap

THERE IS NO 12..

13=1.3mm gap

14=1.4mm gap

15=1.5mm gap

20=2.0mm gap

Simple ehh?

If you have more info.. or new info.. let somebody know!

[psi]

I thought i found a new letter.. but Dohh. its already on there!

[BLACK34]

Great post, but I think this needs to be updated.

Just went on the NGK website and the recommended plug for my R34 GTT is PFR6G-11

Your post doesnt show what the P or F mean.

Also, after a search of the forum I found that most people are using BKR7E or BCPR6ES. Howcome nobody seems to be using the PFRxG-11?? Is it because these are a new model?

[QWK32]

for the PF, P means its a platinum plug and F is the thred type. The BC and BK plugs are coppers.

this chart is easier to understand

Edited July 27, 2008 by QWK32

[vinnie32GTS4]

how do you know what heat range to get???

[QWK32]

how do you know what heat range to get???

in the NGK books i think they recommend 5's for the RB engines, but they can be too hot and cause issues. most people run 6's, some people run 7's, depending on the setup.

[The Dan]

in the NGK books i think they recommend 5's for the RB engines, but they can be too hot and cause issues. most people run 6's, some people run 7's, depending on the setup.

1 heat range colder for every 100-150hp more than stock as a general rule. What happens when you are making more than 600rwhp? Good question...change the plug to a group 9 or something similar. PS. This does not mean heat range 9

[rnbguy]

i bought these from repco bkr5eix 1139 , apparantly their supposed to be 0.8mm =/ i didnt measure them because i cant find my tool