NGK PKR7A Spark Plug – Stock No. 3641
The NGK PKR7A is a reliable, heat range 7 spark plug designed for strong ignition under high load. It helps maintain clean, stable combustion in tuned or hard-driven petrol engines. The resistor design reduces electrical noise that can affect the ECU and other electronics.
A colder heat range 7 plug removes heat from the tip faster than a hotter plug. This helps resist knock and pre-ignition on engines that run higher boost, higher compression, or track-day temperatures. Expect smoother starts, consistent spark at high RPM, and dependable performance over time when correctly gapped and installed.
Use our vehicle lookup to confirm fitment, or check the Vehicle Fitment tab for full details.
| Part Number | PKR7A |
|---|---|
| NGK Stock Number | 3641 |
| GTIN | 087295136416 |
| Category | 686 – Spark Plug |
| Heat Range (NGK) | 7 (colder than 6) |
| Resistor | Yes |
| Thread Diameter | 14 mm |
| Thread Reach | 19 mm |
| Hex Size | 16 mm |
| Seat Type | Gasket |
| Insulator Projection | Projected tip |
| Centre Electrode | Copper core, nickel alloy |
| Ground Electrode | Standard cut |
| Pre-set Gap | Typically 0.8 mm (check and adjust to your spec) |
| Terminal Type | Solid |
- Best choice when the engine builder or ECU tuner specifies a colder plug for knock control.
- Helps maintain a clean firing tip during long high-temperature runs.
Note: Always confirm gap and torque to the vehicle manufacturer or tuner’s spec. Mis-gapping or over-tightening can damage the plug or cylinder head.
The price displayed is for a single plug, please add the desired amount to your basket.


