NGK Spark Plug - B4ES

NGK B4ES (4129) - Standard Spark Plug / Sparkplug - Nickel Ground Electrode. This spark plug is re...

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Product Information

Full details

The NGK B4ES (4129) is a high-quality standard spark plug designed for owners of petrol engines who require reliable ignition performance for daily operation. It is an ideal choice for maintenance enthusiasts seeking an OEM-standard replacement featuring a durable nickel ground electrode. Note that this specific model does not include internal interference suppression, meaning it may not be suitable for modern electronic ignition systems sensitive to electromagnetic interference.

All features

Model Part Number	B4ES
Brand	NGK

Extended Product Information

FAQs

What is the hex size for the B4ES?

The hex nut size is 20.8mm.

Does this spark plug have interference suppression?

No, this model does not include internal interference suppression.

What is the thread length of this plug?

The B4ES has a thread length of 19mm.

What material is the center electrode made of?

The center electrode is made of nickel.

Can I use this in any engine?

No, you must verify that the 14mm thread and 19mm reach are compatible with your specific engine's cylinder head.

What is the spark projection?

The spark projection is 1mm.

Troubleshooting

Engine fails to start or runs rough

Check the plug gap and inspect for heavy carbon deposits or a cracked porcelain insulator.

Visible electrical arcing on wires

Ensure the SAE connector is fully seated and the spark plug wire is in good condition.

Plug appears wet with fuel

Check the carburetor or fuel injection settings, as the engine may be running too rich.

Pros and Cons

Pros

High-quality construction from a trusted industry manufacturer
Reliable ignition performance in standard petrol engines
Durable nickel center electrode for extended service life
Precise gasket seat design for a secure, airtight seal

Cons

No internal interference suppression (not for sensitive electronics)
Limited to specific thread and reach specifications
Not suitable for high-performance forced-induction engines

Setup, Compatibility & Care

To ensure peak performance, verify that your engine's service manual specifies the B4ES (or the 4129 cross-reference).

Preparation: Ensure the engine is cool to the touch before attempting removal.
Installation: Clean the area around the plug to prevent debris from falling into the combustion chamber. Thread the plug by hand to avoid cross-threading, then use a 20.8mm hex socket to tighten to the manufacturer's specified torque.
Care: Inspect the electrodes periodically for signs of carbon buildup, oil fouling, or electrode erosion. Replace the plugs according to the service interval defined by your engine manufacturer.