NGK R7420-9 Spark Plug

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Rating
Brand	Code
4.5 / 5 Overall
NGK	R7420-9
4.5 / 5 Materials
Platinum	Iridium
Ground electrode	Center electrode
4.5 / 5 Design
Slant	Fine Wire
Ground type	Center type

Specifications
Gap	Heat range
0.7mm (.028")	9
⌀14mm	1.25mm
Thread diameter	Thread pitch
21mm (.827")	21mm (13/16")
Reach	Hex size
Gasket	Solid
Seat	Terminal
1	Non-Projected
Ground count	Projection

Cross-reference and alternatives

How we find alternative spark plugs How we rate spark plugs

Cross-reference (1)

Alternative spark plugs found in cross-reference docs provided by manufacturers

IRE01-27

Iridium-Platinum

4.3/ 5

.028"21.5mm, ⌀14x1.25HR 27

Deep reference (9)

A second level of cross-reference: if A=B and B=C, then A=C

R6725-9

Platinum

4.0/ 5

.028"21.5mm, ⌀14x1.25HR 9

BR8EQ

Copper

3.3/ 5

.049"19mm, ⌀14x1.25HR 8

BR8ET

Copper

3.3/ 5

.041"19mm, ⌀14x1.25HR 8

2526

Copper

2.9/ 5

.055"19mm, ⌀14x1.25HR 5

BUR7EQ

Copper

0.0/ 5

.055"19mm, ⌀14x1.25HR 7

BUR7EQP

Copper-Platinum

0.0/ 5

.055"19mm, ⌀14x1.25HR 7

BUR8EQP

Copper-Platinum

0.0/ 5

.055"19mm, ⌀14x1.25HR 8

BUR9EQ

Copper

0.0/ 5

.055"19mm, ⌀14x1.25HR 9

BUR9EQP

Copper-Platinum

0.0/ 5

.055"19mm, ⌀14x1.25HR 9

One step colder (1)

Colder spark plugs with same characteristics for moderately tuned engines (75–100 hp increase)

R7420-10

Iridium-Platinum

4.5/ 5

.028"21mm, ⌀14x1.25HR 10

Two steps colder (1)

Two steps colder spark plugs with same characteristics for heavily modified engines (150-200 hp increase)

R7420-11

Iridium-Platinum

4.5/ 5

.028"21mm, ⌀14x1.25HR 11