Chapter 10 Ignition Systems
193
Goodheart-Willcox Publisher
Figure 10-5.
This chart explains how to identify spark plugs.
Spark Plug Code Interpretation
10: 1.0mm (.040″)
11: 1.1mm (.044″)
13: 1.3mm (.050″)
14: 1.4mm (.055″)
15: 1.5mm (.060″)
20: 2.0mm (.080″)
Thread
diameter
A:
18mm
B:
14mm
C:
10mm
D:
12mm
E:
8mm
J:
12mm x 19mm
Reach
Construction
M:
Compact type
P:
Projected
insulator type
R:
Resistor type
U:
Surface discharge
Z:
Inductive
supressor type
Heat rating
numbers
Reach Firing and
construction
2 Hot
4
5
6
7
8
9
10 Cold
E:
19mm
(3/4″)
F:
Taper
seat
H:
12.7mm
(1/2″)
L:
11.2mm
(7/16″)
Z:
21mm
(53/54″)
Blank
18mm
Ø
12mm
(31/64″)
14mm
Ø
9.5mm
(3/8″)
A:
Special design
B:
Single ground
special alloy
C:
Dual ground
special alloy
G:
Racing type
GV:
Racing version
of V-type
L:
Half heat range
S:
Standard center
electrode
V:
Fine wire center
electrode
X:
Booster gap
Y:
V-grooved center
electrode
PREFIX SUFFIX
Standard type Projected insulator type Taper seat type V-type Surface discharge type
Crosscuts and gaps styles of spark plugs
WIDE GAP
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