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NGK 6817 Spark Plug
| Brand | NGK 6817 |
|---|---|
| Resistance | 5000 |
| Ground Electrode Tip Design | Standard |
| Ground Configuration | Standard |
| Ground Electrode Core Material | Nickel |
| Electrical Terminal Type | Stud |
| Center Electrode Core Material | Copper |
| Center Electrode Tip Material | Nickel |
| Pre-Gap Size | .036 |
| Ground Electrode Quantity | 1 |
| Hex Size | 14 |
| Insulator Height | 50.00 |
| Manufacturer Heat Range | 8 |
| Seat Type | Flat |
| Reach | 26.5 |
| Thread Diameter | 10.00 |
| Part Number | Lmar8a-9s |
| Stock Number | 6817 |
| Fits | — |
OE legacy. Built to original equipment standards for dependable performance.
Copper core. Helps promote consistent ignition and efficient spark delivery.
Standard design. A straightforward spark plug for broad automotive, marine, and small-engine use.
Cross-references AMS Automotive 6817 and 31908-MGC-003 for the same application. See all 2.
NGK LMAR8A-9S Spark Plug Overview
The NGK 6817 spark plug is a standard replacement ignition component built around NGK’s long-running OE manufacturing experience. It uses a copper center electrode core, nickel center and ground electrode tips, and a 5,000 ohm resistor to support stable ignition performance in the correct application.
For drivers searching for an NGK spark plug for Honda Civic or Acura applications, this part number 6817 is a direct-reference option where specified by the vehicle catalog. It is also identified as LMAR8A-9S.
Key Features
- NGK Standard Spark Plug line for OE-style ignition service
- Part number 6817, also listed as LMAR8A-9S
- 5,000 ohm resistor for ignition noise suppression
- Copper center electrode core for dependable heat transfer
- Nickel center and ground electrode tip materials
- Standard ground electrode design with one ground electrode
- Pre-gapped at .036 inch
- 10.00 mm thread diameter, 26.5 mm reach, flat seat
- 14 mm hex size and stud terminal type
- Manufacturer heat range 8
Product Details
NGK’s Standard Spark Plug line focuses on original-equipment-style construction and consistent fitment standards for domestic and import vehicles. The 6817 spark plug is built with a nickel-tipped center electrode, nickel ground electrode tip, and standard ground configuration to match the requirements of the specified engine application. Its 5,000 ohm resistance helps control electrical interference, while the .036 pre-gap supports straightforward service replacement when the engine calls for this specification.
This part cross-references AMS Automotive 6817 for the same application. If you are replacing a worn spark plug in a Honda Civic or Acura engine that calls for LMAR8A-9S, NGK 6817 provides the correct OE-style specification match.
Common Issues This Part Can Address
- Hard starting caused by worn or fouled spark plugs
- Rough idle from inconsistent spark delivery
- Misfire conditions related to degraded plug electrodes
- Reduced fuel efficiency from weak ignition performance
- Loss of throttle response in the specified engine application
Installation Notes and Tips
Verify the engine calls for LMAR8A-9S / NGK 6817 before installation. Check the plug gap against the vehicle service specification, inspect the ignition coil and plug boot condition, and install to the manufacturer’s torque specification for the cylinder head material. For Honda Civic and Acura service work, confirm thread reach, seat type, and terminal style match the original plug before final assembly.
Quality Assurance
NGK is a major OE spark plug supplier with more than 80 years of automotive manufacturing experience. The brand’s North American and global production and distribution network supports consistent product availability and OE-level manufacturing standards for ignition service parts.
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