Page 9 - NGK-sytytystulpat-klassikkoautoihin

Symbols used on spark plugs

The standard symbols are shown here. In addition, several special designations are used.

Plug Type Thread dimensions /
Hex. size
D High ignitability plug :
Double fine electrodes KA Ø12.0 19.0mm Dichtring 14,0

I Iridium spark plug KB Ø12.0 19.0 mm Gasket Bi-Hex 14.0
L Long thread reach plug MA Ø10.0 19.0 mm Gasket 14,0
P Platinum spark plug NA Ø12.0 17.5 mm Tapered-seat 14,0
S High ignitability plug :
F Ø14.0 19.0 mm Gasket 16,0
Square tip type
Z Extended Gap G Ø14.0 19.0 mm Gasket 20,8
Above alphabets are occasionally 18,0
used in combination. J Ø12.0 19.0 mm Gasket 16,0
Ex. ILFR…, PLZFR… 16,0
"L", long thread reach, is prior to other K Ø12.0 19.0 mm Gasket 16,0
letters which stand for 16,0
thread reach. L Ø10.0 12.7 mm Gasket 16,0
Ex. 20,8
• Gasket type M Ø10.0 19.0 mm Gasket 20,8
16,0
FR5AP-11;reach 19.0mm T Ø14.0 17.5 mm Tapered-seat
LFR5AP-11;reach 26.5mm
• Tapered-seat type U Ø14.0 11.2 mm Tapered-seat
PTR5C-13;reach 17.5mm
PLTR6A-10G;reach 25.0mm W Ø18.0 10.9 mm Tapered-seat

X Ø14.0 9.5 mm Gasket

Y Ø14.0 11.2 mm Tapered-seat

P F R 5 A - 11

Resistor Heat Rating Design Spark gap
R Resistor
2 Hot type A,B,C… None motorcycle:0.7-0.8mm
Suffix code car:0.8-0.9mm
4 -7 0.7mm
5 I One-side Iridium spark plug -9 0.9mm
6 P One-side Platinum spark plug -10 1.0mm
7 -11 1.1mm
8 -13 1.3mm
9 -14 1.4mm
10 Cold type -15 1.5mm

-A Non gasket
-D Metal shell plating spec change
-E Special resistance
-G Copper core ground electrode
-H Special thread type
-J 2-ground-electrode
-K Vibration-resistant ground electrode
-N Special ground electrode
-Q 4-ground-electrode
-S Special gasket
-T 3-ground-electrode

GB VII