NipponDenso Spark Plug Chart

 

Example (note that not all 7 fields will always be used, such as in K20R-U):

W 16 E X R -U 11

 

First box from example (W):
THREAD and HEX SIZE
Letter Thread Hex Size Description
M
L
MA
J*
P*
S
SF
W
 
PQ*
Q*
QJ*
PK* +
K* +
KJ* +
T
WA
X
U
U		 18mm
18mm
18mm
14mm
14mm
14mm
14mm
14mm
 
14mm
14mm
14mm
14mm
14mm
14mm
14mm
14mm
12mm
10mm
10mm		 1"
7/8"
13/16"
13/16"
13/16"
13/16"
13/16"
13/16"
3/4"
5/8"
5/8"
5/8"
5/8"
5/8"
5/8"
5/8"
5/8"
18.0mm
5/8"
14.0mm		  
 
Taper Seat
Extended Electrode
Platinum Tipped Electrodes
Special Surface Gap
Surface Gap
 
For Compact Type
Platinum Tipped Electrodes
 
Extended Electrode
Platinum Tipped Electrodes
 
Extended Electrode
Taper Seat
Taper Seat (Compact Type)
 
 
For Compact Type (U20M-U)
* Reach 3/4"     + ISO Std.

 

Second box from example (16):
HEAT RANGE NUMBER

HOT   <————————————————>   COLD
9  14  16  20  21*  22  24  25*  27  29*  31  32*  34  37
* Special heat rating number

 

Third box from example (E):
THREAD REACH
Letter Reach
A
 
B
C
E (Flat Seat)
 
E (Taper Seat)
F
FE
G
H
L
M
N (Taper Seat)
None
 
 
None (Taper Seat)
  		3/4" and 0.28" Proj Length
0.787"
3/4" and 0.37" Proj Length
3/4" and 0.20" Proj Length
3/4"
0.787"
0.708"
1/2"
3/4" Half Thread
0.858"
3/4" and 0.33" Proj Length
7/16"
0.339"
0.708" Half Thread
15/32"
3/8"
3/4"
0.460"
0.325"

 

Fourth box from example (X):
SPECIAL DESIGN
Letter Description
A
B
D
K
LM
M
N
P
S
T
X		 2 ground electrodes for Mazda rotary
3 ground electrodes for Mazda rotary
4 ground electrodes for Mazda rotary
Special type for Honda CVCC eng.
Compact type (Hex. 13/16")
Compact type (Hex. 3/4")
Racing type (Retracted insulator and Nickel ground electrodes)
Projected tip
Non-projected tip
2 ground electrodes
Extra projected tip

 

Fifth box from example (R):
INTERNAL CONSTRUCTION
Letter Description
R
None		 Resistor
Standard

 

Sixth box from example (-U):
SPECIAL DESIGN
Letter Description
-U
-Z
-GL
-V
-S
-L
 
-P
-US
-N		 With U-Grooved ground electrode
Platinum center electrode with taper shaped ground electrode
Platinum center electrode
Fine wire center electrode
Semi-surface gap type
Special type for Honda CVCC eng.
Extra project type for mopeds
A double coating of platinum on the ground electrode
Star center electrode with U-Groove ground electrode
Special type for Yamaha, Kawasaki

 

Seventh box from example (11):
GAP

Number

 Gap

8
9
10
11
13
14
15
20

 0.8mm (0.032")
0.9mm (0.035")
1.0mm (0.040")
1.1mm (0.044")
1.3mm (0.050")
1.4mm (0.055")
1.5mm (0.060")
2.0mm (0.080")