What is the gap on a Motorcraft spark plug?
There is no single universal gap for Motorcraft spark plugs. The correct gap depends on your engine and the specific plug type; most Ford/Motorcraft applications use a narrow working range, typically around 0.028 to 0.060 inches (0.7 to 1.5 mm).
In this article, we explain how the gap is determined, how to find the exact specification for your Motorcraft plug, and how to measure and set the gap correctly when servicing Ford, Lincoln, or Mercury vehicles. We'll also cover what to do if you replace with a different plug type.
What determines the spark plug gap?
The gap is chosen to ensure efficient ignition, proper flame kernel development, and reliable cold starting. It depends on engine compression, ignition timing and system, and the plug's electrode design. The vehicle manufacturer specifies the preferred gap in the owner's manual or service information. Motorcraft plugs are designed to meet those specs, and some are shipped pre-gapped, but you should verify the exact value for your engine.
Motorcraft plug types and pre-gap status
Motorcraft offers copper-core, platinum, and iridium plugs. The gap tolerance and recommended gap can vary between these types and by engine. Some plugs ship pre-gapped to a standard value, but for Ford engines with unique compression or ignition demands, the spec may differ; always check the exact spec for your model.
Typical gap ranges you might see with Motorcraft plugs
Before listing the ranges, note that exact specs vary by engine. The following ranges are common starting points for many Ford/Motorcraft installations:
- General range for most Motorcraft plugs: 0.028–0.060 inches (0.7–1.5 mm).
- Typical Ford/Motorcraft target gaps for many engines: about 0.040–0.052 inches (1.0–1.3 mm).
- Higher-compression or performance engines may require closer gaps, around 0.030–0.040 inches (0.76–1.0 mm).
- Pre-gapped vs. non pre-gapped: Many plugs ship pre-gapped; verify the specified gap and adjust only if required by the engine spec.
In practice, the exact gap you should use is engine-specific. The ranges above are guidance rather than universal values.
How to measure and set the gap safely
Before starting, have the exact gap specification from your vehicle’s manual or Motorcraft packaging. If you’re replacing plugs, verify whether the new plugs are pre-gapped to that spec. If adjustment is needed, follow these steps carefully:
- Confirm the exact gap value for your engine from the owner's manual or Motorcraft packaging.
- Inspect the new plug to determine whether it is already pre-gapped to the specified value.
- Using a proper spark plug gauge, measure the gap between the center electrode and the ground strap. If adjustment is required, gently bend the ground strap to increase or decrease the gap by small amounts. Do not bend the center electrode.
- Re-measure to ensure the gap is within tolerance.
- Reinstall the plug and torque to the engine’s specification. Do not over-tighten.
Note: If you’re unsure or dealing with a high-performance or direct-injection engine, consult a professional. Some engines require precise gaps that are difficult to achieve without the right tools.
Summary
There isn't a single universal gap for Motorcraft spark plugs. The gap depends on the engine and the specific plug type. Typical ranges span roughly 0.028 to 0.060 inches (0.7–1.5 mm), with many Ford/Motorcraft applications landing around 0.040–0.052 inches (1.0–1.3 mm). Always refer to the vehicle's owner manual or the spark plug packaging for the exact specification, and use a proper gap tool to verify or set the gap before installation. Adhering to the correct gap ensures reliable ignition, optimal performance, and proper emissions control.
What is the spark plug gap on a Ford f150 Powerboost?
Engine Specifications
| Engine | 2.7L EcoBoost | 3.5L V6 Ecoboost |
|---|---|---|
| Firing order | 1-4-2-5-3-6 | 1-4-2-5-3-6 |
| Ignition system | Coil on plug | Coil on plug |
| Spark plug gap | .028-.031 (0.7 - 0.8 mm) | .030-.033 in. (0.75 - 0.85 mm) |
| Compression ratio | 10.0:1 | 10.0:1 |
What gap should a RC12YC spark plug be?
The correct spark plug gap for the Champion RC12YC is 0.0300.0300.030 inches (0.760.760.76 mm), though it may also be specified as a range of 0.0320.0320.032 to 0.0380.0380.038 inches. It is recommended to check and adjust the gap to the correct specification using a spark plug gapping tool, as new plugs may not be perfectly gapped.
This video demonstrates how to gap a spark plug: 42sThe Lawnmower LadyYouTube · Jan 25, 2021
Standard gap
- 0.0300.0300.030 inches: (0.760.760.76 mm)
Alternative range
0.032 to 0.038 inches.
How to gap
- Always check the gap on a new or cleaned spark plug before installing it.
- Use a spark plug gapping tool or feeler gauge to measure the gap.
- Adjust the gap by carefully bending the ground electrode. To open the gap, use the tool to pry it open; to close it, gently tap the ground electrode against a hard surface or use the gapping tool.
- Ensure you have the correct gap specification for your specific engine application.
You can watch this video to learn how to gap a spark plug: 1mJB ReviewsYouTube · Jul 31, 2023
Do motorcraft spark plugs come gapped?
Yes, Motorcraft spark plugs are typically pre-gapped from the factory, but it is highly recommended to always check the gap before installing them, especially for platinum and iridium plugs. While many are correct, the gap can be altered during shipping, and it's essential to ensure the gap is set to the correct specification for your specific engine.
This video demonstrates how to check the gap on a spark plug: 57sMACTFORDEDGEYouTube · Dec 24, 2016
Why you should always check
- Protection during shipping: The gap can be easily knocked out of specification during transport, even with the protective packaging.
- Variations for different engines: Some spark plugs are designed to fit multiple engines, so the factory gap may not be correct for your specific vehicle.
- Preventing damage: For platinum and iridium plugs, using the wrong gapping tool can damage the delicate electrode tip. Using a flat steel or plastic feeler gauge is recommended for checking and making minor adjustments.
How to check and adjust the gap
- Carefully remove the spark plug from its protective packaging.
- Use a proper spark plug gap tool to check the gap against the manufacturer's specification for your vehicle.
- If the gap is incorrect, use a gapping tool to gently open or close it to the correct setting. Be very careful to avoid damaging the electrode.
- If the spark plug is an iridium or platinum type, and you need to make an adjustment, be extremely careful and only use a tool that will not damage the tip, as this can prevent the plug from performing correctly, say Reddit users.
What is the correct spark plug gap for?
The gap setting is different for each vehicle but most are somewhere between 0.028" and . 060". Consult the owner's manual or Champion ® catalog to find the recommended setting for the vehicle you're working on.
