NGK5 Matches
BKR6E
Thread14 mm x 1.25
Gasket OD19.0 mm Reach
HeightHex 16.0 mm (5/8")
Bypass ReliefGap 0.8 mm (0.032")
Spark Plug Cross-Reference Matrix
Automotive and small engine spark plug thread, reach, heat range and gap interchange.
Verified Spark Plug Part References (1)
Technical Reference Standard
Spark Plug Cross-Reference & Heat Range Guide
Understanding heat range scales, thread reach, electrode metallurgy, and gap specifications.
1
Heat Range Numbering Inversion
Different brands use inverse heat range scales. NGK uses higher numbers for colder plugs (e.g. 7 is colder than 5), while Champion and Bosch use higher numbers for hotter plugs (e.g. 12 is hotter than 8). Never cross-match numbers blindly without conversion matrices.
2
Thread Reach & Hex Size
Thread reach (e.g. 19 mm / 0.75 in vs 12.7 mm / 0.5 in) must match combustion chamber specifications exactly. Installing an excessive reach plug can collide with piston crowns.
3
Electrode Metallurgy Grades
Copper core plugs offer superior electrical conductivity with 20k-30k mile lifespans. Platinum and Iridium fine-wire electrodes deliver 80k-100k mile durability and lower voltage requirements under high boost.
4
Pre-Gap Tolerances
Standard plug gaps range from 0.028 in (0.7 mm) to 0.044 in (1.1 mm). Forced induction and high-compression engines require tighter gaps to prevent spark blowout.
Frequently Asked Questions
Spark Plug Interchange FAQ
How do heat ranges convert between NGK, Champion, and Bosch?
NGK heat scale is inverse to Champion and Bosch. An NGK heat range 6 corresponds roughly to Champion 9-10 and Bosch 7-8. Consult the FilterEquiv cross-table for exact part-level calibrations.
Can I replace a copper spark plug with an Iridium equivalent?
Yes. Iridium equivalents share identical thread pitch, reach, and heat dissipating properties while providing greater resistance to spark erosion and fouling.
Should I apply anti-seize lubricant to spark plug threads?
Most modern plugs (NGK, Champion) feature trivalent chrome or zinc plating designed for dry installation. If anti-seize is used, reduce tightening torque by 20% to avoid over-torquing the cylinder head.
What happens if I install a spark plug with an incorrect heat range?
A plug that is too hot can cause pre-ignition, detonation, and melted electrode tips. A plug that is too cold will fail to burn off carbon deposits, resulting in misfires and carbon fouling.
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