What Is a Spark Plug Cross Reference?
A spark plug cross reference chart maps one brand's plug part number to the equivalent plug from another brand. If your vehicle specifies a Champion RA8HC or a Denso IK20, an NGK cross reference chart tells you the NGK part number with equivalent specifications — heat range, thread size, reach, gap, and electrode type.
Cross references are useful when your preferred brand isn't in stock, when you're comparing prices, or when you want to upgrade from a standard copper plug to NGK's iridium equivalent.
Where to Find NGK Cross Reference Charts
NGK publishes their cross-reference database on their official website at ngksparkplugs.com. You can search by competitor part number or by vehicle year/make/model/engine. The database covers hundreds of thousands of cross-references from brands including:
- Champion
- ACDelco
- Autolite
- Denso
- Bosch
- Motorcraft
- Splitfire
How to Use the Cross Reference
Step 1: Find Your Current Part Number
Check your owner's manual, existing plug box, or vehicle lookup tool to identify the OEM part number (e.g., Champion RC12YC or ACDelco 41-110).
Step 2: Enter the Competitor Part Number
In the NGK cross-reference search, enter the competitor's part number. NGK will return the equivalent NGK plug — usually more than one option (standard, platinum, iridium tiers).
Step 3: Verify Specifications
Cross references are generally equivalent, but always verify these specs match your vehicle's OEM requirement:
- Heat range — Different brands use different heat range numbering scales. Verify the temperature characteristics match.
- Gap — Cross-reference plugs may have a different factory pre-set gap. Always gap your plugs to the vehicle manufacturer's specification.
- Reach — Thread reach must match your engine (typically 12mm, 19mm, or 26mm for automotive plugs).
- Thread diameter — Usually 10mm, 12mm, or 14mm.
Step 4: Choose Your Tier
NGK typically offers 2–3 options when you cross-reference a competitor's copper plug:
- NGK copper equivalent (same spec, possibly lower cost)
- NGK G-Power Platinum (upgrade to platinum, ~60K life)
- NGK Iridium IX or Laser Iridium (premium upgrade, longest life)
If your vehicle originally came with copper plugs, upgrading to NGK Iridium IX is a popular and well-regarded choice that reduces future replacement frequency.
Popular Cross References
| Champion | NGK Equivalent | Application |
|---|---|---|
| RC12YC | BPR5EY | Small engines, some GM |
| RA8HC | B8ES | Older performance engines |
| RS14YC | BR5ES | Various small engines |
Important Note on Cross References
Cross-references are equivalent, not identical. Minor differences in insulator design, electrode material, and heat range tolerance may exist. For most daily-driving applications, the cross-reference is a perfectly safe substitution. For high-performance, racing, or critical applications, verify specifications against the engine builder's specs.
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