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NGK 4421 Spark Plug
| Brand | NGK 4421 |
|---|---|
| Resistance | 5000 |
| Ground Electrode Tip Design | Standard |
| Ground Configuration | Standard |
| Ground Electrode Core Material | Nickel |
| Electrical Terminal Type | Non-removable nut |
| Center Electrode Core Material | Copper |
| Center Electrode Tip Material | Nickel |
| Pre-Gap Size | .036 |
| Ground Electrode Quantity | 1 |
| Hex Size | 5/8 |
| Insulator Height | 50.50 |
| Manufacturer Heat Range | 4 |
| Seat Type | Flat |
| Reach | .75 |
| Thread Diameter | 14.00 |
| Part Number | Bkr4e |
| Stock Number | 4421 |
| Fits | — |
OE supplier heritage. Built by NGK, a long-time original equipment spark plug manufacturer.
Copper core design. Helps promote consistent ignition performance and heat transfer.
Standard replacement fit. Flat seat spark plug with a non-removable nut terminal.
Cross-references AMS Automotive 4421, Carlson 7816 and Champion Spark Plug 431 for the same application. See all 14.
NGK BKR4E V-Power Spark Plug
The NGK V-Power Spark Plug 4421 is a copper-core, nickel-tipped spark plug built for stable ignition performance and consistent combustion. With a 0.036 pre-gap, 14 mm thread diameter, 0.75 reach, and flat seat design, it is a direct-service ignition component for a wide range of import and domestic applications.
Key Features
- NGK V-Power Spark Plug, part number 4421
- Part number BKR4E / stock number 4421
- Copper center electrode core for dependable heat transfer
- Nickel center and ground electrode tip materials
- Standard ground electrode design with one ground electrode
- 5,000 ohm resistance for ignition system compatibility
- 0.036 pre-gap, 14 mm thread diameter, 0.75 reach
- Flat seat with 5/8 hex size and non-removable nut terminal
V-Power Spark Plug Line
NGK’s V-Power line is built around a standard-service spark plug design that supports reliable ignition in everyday driving conditions. The BKR4E configuration uses a copper core and nickel electrode materials to promote steady spark delivery and consistent operation in engines that call for this plug specification.
Detailed Description
NGK 4421 is a BKR4E spark plug engineered to meet original-equipment-style requirements for many vehicles, including select Honda Civic and Toyota Corolla applications where this plug specification is called for. As part of NGK’s long-running ignition product range, it reflects the company’s experience as a major OE supplier for North American and global vehicle platforms. This spark plug is also cross-referenced to Champion 431 and 431S for the same application.
What It Helps Address
- Hard starting caused by worn or fouled spark plugs
- Rough idle from inconsistent spark delivery
- Misfire conditions related to plug wear or incorrect gap
- Reduced throttle response from weak ignition performance
- Fuel economy loss tied to degraded combustion efficiency
Installation Notes and Tips
Verify the engine calls for BKR4E / 4421 before installation. Confirm thread diameter, reach, seat type, and pre-gap against the service specification, and inspect the ignition system for carbon tracking, oil fouling, or coil issues before fitting new plugs. Use the correct torque procedure for the cylinder head material and recheck gap only if the application requires it.
Quality Assurance
NGK manufactures spark plugs to OE standards and supports a broad range of automotive, motorcycle, marine, and small-engine applications. The 4421 spark plug is built with the brand’s established manufacturing and distribution network behind it, supporting consistent product quality and application coverage.
| Year | Make | Model | Position | Notes |
|---|---|---|---|---|
| No rows match your filter. | ||||