Spark Plug Info!

Everything you ever wanted to know about ND & NGK plugs!

Be sure and thank Vice President Ellis Holman eholman@comcast.net for providing this info.

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NGK Spark Plug Chart

 

Example (note that not all 6 fields will always be used, such as in BKR6EY):

B CPR 6 E S -11

 

First box from example (B):
Letter Thread Diameter
A 18mm
B 14mm
C 10mm
D 12mm
J 12mm

 

Second box from example (C, P, R):
Letter Construction
C Hex size 5/8"
K 5/8" projected tip (ISO)
M Compact type
P Projected insulator type
R Resistor type
U Surface or semi-surface discharge type
Z Inductive resistor

 

Third box from example (6):
Heat Range
2 (Hot)  <ÉÉÉ>  12 (Cold)

 

Fourth box from example (E):
Letter Thread Reach
E 19mm (3/4")
F Tapered seat
H 12.7mm (1/2")
L 11.2mm (7/16")
No symbol:
  18mmè = 12mm reach
  14mmè = 9.5mm (3/8") reach

 

Fifth box from example (S):
Letter Firing End Construction
A Special design
B Special design for Honda CVCC
C Low angle ground electrode
G Fine wire nickel alloy center electrode
GV Gold-palladium center electrode
Special construction of V-type
Racing use
H Partial thread
K 2 ground electrodes for Toyota / BMW
L Half heat range
LM Compact type for lawn mower
M 2 ground electrodes for Mazda rotary engine
N Special side electrode
P Premium platinum
Q 4 ground electrodes
R Special ground electrode
S Standard 2.6mmè center electrode
T 3 ground electrode
U Semi-surface discharge
V Fine wire gold-palladium center electrode
VX High performance platinum
W Tungsten electrode
X Booster gap
Y V-grooved center electrode
Z Thick 2.9mmè center electrode

 

Sixth box from example (-11):
Number Gap
-8 0.8mm (0.032")
-9 0.9mm (0.036")
-10 1.0mm (0.040")
-11 1.1mm (0.044")
-13 1.3mm (0.050")
-14 1.4mm (0.055")
-15 1.5mm (0.060")
-20 2.1mm (0.080")

 

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