Description
NGK B4ES Spark Plug – Stock No. 4129
A reliable, hot heat-range, non-resistor spark plug for classic and small-capacity engines that specify a 14 mm long-reach gasket-seat plug. Designed for steady ignition performance and easy starting.
- Nickel alloy centre electrode with copper core for consistent spark
- Non-resistor design for a strong spark signal
- Long 19 mm reach with gasket seat for common classic fitments
- Built to NGK standards for durability and fouling resistance
Important: This is a non-resistor plug. If you experience radio interference or your vehicle uses sensitive electronics, choose an NGK R-type equivalent if specified by the manufacturer.
Fitment guidance
Commonly used in classic cars, motorcycles, marine and small engines that require a 14 mm, 19 mm reach, non-projected, non-resistor plug in a hot heat range. Always confirm with our vehicle lookup or the Vehicle Fitment tab and your owner’s manual.
Technical specifications
| Part number | NGK B4ES |
| Stock number | 4129 |
| GTIN | 087295141298 |
| Category | 686 – Spark Plug |
| Thread diameter | 14 mm |
| Thread reach | 19 mm |
| Hex size | 20.8 mm |
| Seat type | Flat seat with gasket |
| Heat range | 4 (hot) |
| Resistor | No |
| Projection | Non-projected tip |
| Centre electrode | Nickel alloy with copper core |
| Ground electrode | Standard single ground |
| Factory gap | Approx. 0.7 mm (check and set to OE spec) |
| Tightening | Install to manufacturer torque spec. For new gasket plugs, typically 1/2 turn after finger-tight if torque data unavailable. |
Why it matters
A correct heat range and reach help prevent fouling and pre-ignition. The B4ES delivers a clean, reliable spark for smoother idle and dependable starts when specified for your engine.
The price displayed is for a single plug, please add the desired amount to your basket.
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