Identifying Spark Plugs
Identifying DENSO Spark Plugs
Thread and Hexagon size: W 16EXRU11
Letter | Thread Size | Hex. Size | Description | |
I | 8mm | 13.0mm | 0.4mm Iridium centre electrode | |
L | 18mm | 22.0mm | ||
M | 18mm | 25.4mm | ||
MA | 18mm | 20.6mm | Taper seat | |
# | J | 14mm | 20.6mm | Extended electrode |
# | P | 14mm | 20.6mm | Platinum-tipped electrodes |
# | PQ | 14mm | 16.0mm | Platinum-tipped electrodes |
# | Q | 14mm | 16.0mm | |
# | QJ | 14mm | 16.0mm | Extended electrode |
# | K | 14mm | 16.0mm | ISO |
# | KJ | 14mm | 16.0mm | ISO Extended electrode |
# | PK | 14mm | 16.0mm | Platinum-tipped electrodes |
# | PT | 14mm | 16.0mm | Platinum-tipped electrodes |
S | 14mm | 20.6mm | Special surface gap for Mazda. Thread reach 21.5mm | |
SF | 14mm | 20.6mm | Surface gap | |
SK/SVK | 14mm | 16.0mm | Iridium-tipped centre electrode & Platinum-tipped ground electrode | |
T | 14mm | 16.0mm | Taper seat | |
W | 14mm | 20.6mm | ||
TR | 14mm | 20.6mm | Thread reach 12.7mm | |
X | 12mm | 18.0mm | ||
XU | 12mm | 16.0mm | ||
U | 10mm | 16.0mm | ||
Y | 8mm | 13.0mm | ||
# = 19.0mm thread reach |
Heat Range: W 16 EXRU11
Hot | Cold | ||||||||
9 | 14 | 16 | 20 | 22 | 24 | 27 | 31 | 34 | 37 |
Thread Reach: W16 E XRU11
Letter | Reach | Example |
D | 19.0mm + 1.5 | KJ20DRM11 |
E (Flat seat) | 19.0mm (3/4") or 20.0mm | W16EXRU / W25EBR |
E (Taper seat) | .708" | T16EPRU |
F | 12.7mm (1/2") | W20FPU |
FE / UH | 19.0mm (3/4") Half thread | U24FER9 |
G | 21.8mm | X27GPRU |
H | 26.5mm | K16HPRU11 |
L | 11.2mm (7/16") | W14L |
N | 17.5mm Half thread | T16NRU11 |
V (Taper seat) | 25.0mm | PT16VR13 |
No Letter:- | ||
18mm thread (Flat seat) | 12.0mm | M24S, L14U |
14mm thread (Flat seat) | 9.5mm (3/8") | W20SU, W9PRU |
18mm thread (Taper seat) | .480" | MA16PRU |
14mm thread (Taper seat) | .460" or .325" | T16PRU, T20MU |
Electrode Design: W16E X RU11
Letter | Description | Example | |
A | Dual ground electrodes for Mazda RE | W22EA | |
# | A | Electrode projection (7.0mm) | QJ16ARU |
B | Triple ground electrodes | W20EPB | |
# | B | Electrode projection (9.5mm) | J16BRU |
# | C | Electrode projection (5.0mm) | QJ20CR11 |
D | 4-ground electrodes for Mazda RE | W27EDR14 | |
# | H | Electrode projection (8.5mm) | QJ16HRU |
K | Special type for Honda CVCC | W16EKRS11 | |
LM | Special type for lawn mowers | W14LMU | |
M | Compact type | W20MU | |
MP | Compact Type and projected insulator nose | W22MPRU | |
PT | Racing type (platinum ground electrode) | W27EPT | |
P | Projected insulator nose | W16EPU | |
S | Regular type | W24ESU | |
T | Dual ground electrodes for Toyota T.G.P | W20ETS | |
V | Semi-surface | W20EVRZU | |
X | Extra projected insulator nose | W16EXU | |
AZ | Thin platinum centre electrode and ground electrode | K27AZ | |
# = When suffix is J, KJ or QJ |
Internal Construction: W16EX R U11
Letter | Description |
No Letter | Non resistor |
R | Resistor |
Gap Configuration: W16EXR U 11
Letter | Description | Example |
C | Cut-back ground electrode | W27EMRC |
L | Special type for Honda and extra project type for moped | KJ20CRL11, W14FPUL |
M | Special ground electrode | KJ20DRM11 |
N | Special internal construction | U27ESRN |
P | Platinum-tipped plug for DIS Double Layer | PQ20RP8 |
S | Semi-surface gap | W20EPRS11 |
U | U-groove ground electrode | W16EXU |
US | Star centre electrode with U-groove | W14US |
V | Thin centre electrode | W24ESV |
Z | Tapered ground electrode | VK20PRZ11 |
ZU | Thin platinum centre electrode with tappered ground electrode | W24ESZU |
Spark Gap: W16EXRU 11
Number | Gap (mm) | Gap (inch) |
9 | 0.9mm | .035" |
10 | 1.0mm | .040" |
11 | 1.1mm | .044" |
13 | 1.3mm | .050" |
14 | 1.4mm | .055" |
15 | 1.5mm | .060" |
20 | 2.0mm | .080" |
Identifying NGK Spark Plugs
Thread, Hexagon and Pitch size: BC PR6ES11
Letter | Thread | Pitch | Hex |
A | 18mm | 1.50mm | 25.4mm |
B | 14mm | 1.25mm | 20.8mm |
C | 10mm | 1.00mm | 16.0mm |
D | 12mm | 1.25mm | 18.0mm |
E | 8mm | 1.00mm | 13.0mm |
G | PF 1/2" pipe | 23.8mm | |
AB | 18mm | 1.50mm | 20.8mm |
BC | 14mm | 1.25mm | 16.0mm |
BK | 14mm | 1.25mm | 16.0mm |
DC | 12mm | 1.25mm | 16.0mm |
Part numbers:- BM_A and BPM_A | |||
14mm | 1.25mm | 19.0mm | |
Part number:- CM-6: | |||
10mm | 1.00mm | 14.0mm | |
Taper Seat Types | |||
Hex | |||
A_F type | 20.8mm | ||
B_F type | 16.0mm |
Construction Shape and Features: BC PR 6ES11
Letter | Construction shape/feature |
M | Compact (Bantam) |
L | Short type |
P | Projected centre electrode insulator |
R | Resisitor type |
U | Surface or semi surface discharge |
Z | Inductive suppressor |
Letters may be combined |
Spark Plug Heat Rating: BCPR 6 ES11
Number | Heat Rating (Hot -> Cold) |
2 | Hotter Plug Temp. |
4 | |
5 | |
6 | |
7 | |
8 | |
85 | (8.5) |
9 | |
95 | (9.5) |
10 | |
105 | (10.5) |
11 | |
12 | Colder Plug Temp. |
Thread Reach: BCPR6 E S11
Letter | Detail | Size(mm) |
E | 19.0mm | |
H | 12.7mm | |
L | 11.2mm | |
EH | Total reach | 19.0mm |
EH | Thread | 12.7mm |
BM_A, B_LM types | 9.5mm | |
CMR_A types | 9.5mm | |
No Letter: | ||
A_ type | 12.0mm | |
B_BM_ type | 9.5mm | |
CM_ type | 8.5mm | |
G_ type | 22.5mm | |
Taper seat types: | ||
F | A_F type | 10.9mm |
B_EF type | 17.5mm | |
B_F type | 11.2mm | |
BM_F type | 7.8mm | |
BPM_F type | 7.8mm |
Firing End Construction: BCPR6E S 11
Description | |
CS | Short, angled ground electrode |
CM | Short, angled ground electrode, compact type |
F | Taper seat (no gasket), 'V' - Grooved centre electrode |
FS | Taper seat (no gasket) |
G | Fine wire nickel centre electrode |
K | 2-ground electrodes, intermittent gap |
KC | 2-ground electrodes |
KUB | 2-ground electrodes semi-surface discharge |
T | 3-ground electrodes |
Q | 4-ground electrodes |
P | Platinum tip |
S | Standard super copper core centre electrode |
U | Semi-surface discharge |
V | Fine wire Gold Palladium centre electrode. 0.8mm dia. |
-VG | 'V'-Grooved centre electrode |
VX | Fine wire Platinum centre electrode. 0.8mm dia. |
I | Iridium tip |
IX | Fine wire Iridium centre electrode. 0.6mm dia. |
W | Tungsten electrode |
X | Booster gap (not applicable to 'VX' or 'IX' types) |
Y | 'V'-Grooved centre electrode with extra protection |
Z | 2.9mm dia. centre electrode (not applicable to DPR_Z or G_2Z |
-L | Half heat range |
-LM | Compact design. Insulator top: 14.5mm high |
-N | Strong ground electrode design |
No Letter: 'V'-Grooved centre electrode (14mm thread dia. 19mm reach plugs only, eg: BKR6E |
|
Others: A,B,D etc, - special design |
Spark Plug Gap: BCPR6ES 11
Spark Gap(mm) | |
8 | 0.8mm |
9 | 0.9mm |
10 | 1.0mm |
11 | 1.1mm |
13 | 1.3mm |
14 | 1.4mm |
15 | 1.5mm |
No Number = standard gap |
Identifying BOSCH Spark Plugs
Hex and Thread Size: W R6DC+
Letter | Hex Size | Thread Size |
D | 20.8mm | 18mm x 1.5mm |
F | 16mm | 14mm x 1.25mm |
H | 16mm | 14mm x 1.25mm |
K | 14mm | 14mm x 1.25mm |
M | 26mm | 18mm x 1.5mm |
T | 16mm | 10mm x 1mm |
U | 16mm | 10mm x 1mm |
V | 14mm | 14mm x 1.25mm |
W | 20.8mm | 14mm x 1.25mm |
X | 17.5mm | 12mm x 1.25mm |
Y | 16mm | 12mm x 1.25mm |
Z | 14mm | 12mm x 1.25mm |
Design Type: W R 6DC+
Letter | Description |
B | Water-tight, for shielded ignition cable 7mm dia. |
C | Water-tight, for shielded ignition cable 5mm dia. |
E | Surface gap spark plug without ground electrode |
G | Surface gap spark plug with ground electrode |
H | Half thread |
L | Surface air gap spark plug |
M | For motor sport |
Q | Quickheat |
R | With interference suppression resistor |
Heat Range: WR 6 DC+
Number | Heat Range (Hot -> Cold) |
12 | Hottest |
11 | |
10 | |
9 | |
8 | |
7 | |
6 | |
5 | |
4 | |
3 | |
2 | |
09 | |
08 | |
07 | Coldest |
Thread Length: WR6 D C+
Letter | Total Thread Length | Thread Length | Insulator and Tip Projection |
A | 12.7mm | 11.2mm | 1mm |
B | 12.7mm | 11.2mm | 3mm |
C | 19mm | 17.5mm | 1mm |
D | 19mm | 17.5mm | 3mm |
E | 9.5mm | 1mm | |
F | 9.5mm | 3mm | |
G | 12.7mm | 4mm | |
H | 19mm | 17.5mm | 7mm |
K | 19mm | 17.5mm | 4mm |
L | 19mm | 17.5mm | |
M | 26.5mm | 25mm | 3mm |
N | 26.5mm | 4mm | |
S | 26.5mm | 5mm | |
T | 26.5mm | 7mm |
Electrode Material: WR6D C +
Letter | Description |
C | Copper |
E | Nickel-Yttrium |
P | Platinum |
S | Silver |
I | Platinum-Iridium |
Version: WR6DC +
Letter | Type |
R | Burn-off resistor |
S | 0.7mm gap |
T | 0.8mm gap |
U | 1.0mm gap |
V | 1.3mm gap |
W | 0.9mm gap |
X | 1.1mm gap |
Y | 1.5mm gap |
Z | 2.0mm gap |
+ | Super Plus Technology |
Extra Prefix Letters: | |
D | 2-Ground electrodes |
T | 3-Ground electrodes |
Q | 4-Ground electrodes |
Information quoted and displayed on the this page is strictly copyright Nippon Denso(UK) Ltd, NGKNTL (UK) Ltd, Robert Bosch(UK) Ltd and Champion Automotive(UK) Ltd. All rights reserved. Layout and design copyright RoadRunner Autoparts Ltd.