Typical Spark Plug Number with Symbol Explanation

R H B 37 E

Electrode Design

None - Conventional Single

E - Two Electrode Massive

N - Four Electrode Massive

S - Single Electrode (Iridium)

B - Twin Electrodes(Nickel)

R - Push-wire - 90° to Center

Y - Projected Core Nose

P - Two Electrode (Platinum)

W - Two Electrode (Iridium)

Resistor

None - No Resistor

R - Mil-Spec. Resistor

Erosion Protection

Barrel Style

None - Unshielded

E - Shielded 5/8” - 24 Thread

H - Shielded 3/4” - 20 Thread

(All-Weather Plug)

V - M18X1 - Metric

All Champion Aerospace spark plugs are identiﬁed by type designations as indicated on the following spark plug number

and symbol chart. The symbol is composed of a rating position number, together with preﬁx and sufﬁx numbers to indicate

major plug design characteristics.

Shielded Aviation Outside Gaskets

Spark Plug Champion Military

Shielded Aviation Spark Plugs Part No. Size Speciﬁcation

are manufactured under military M-674 18 mm Solid Copper AN4027-1

speciﬁcation MIL-S-7886B. N-673 14 mm Solid Copper AN4027-2

Mounting Thread Reach Hex Size

B - 18 mm 13/16” (2.06 cm) 7/8” (2.22 cm)

M - 18 mm 1/2” (1.27 cm) 7/8” (2.22 cm)

J - 14 mm 3/8” (.095 cm) 13/16” (2.06 cm)

L - 14 mm 1/2” (1.27 cm) 13/16” (2.06 cm)

U - 18 mm 1-1/8” (2.85 cm) 7/8” (2.22 cm)

N - 14 mm 3/4” (1.90 cm) 13/16” (2.06 cm)

Heat Rating Position

High Number - Hot (50)

Low Number - Cold (26)

Spark Plugs

Spark Plug Type Designation System