2017 Ford F-350 Super Duty: Spark Plug Type, Gap & Torque

Quick reference

Why the right plug matters

The spark plug is a small but critical component in your truck's ignition system. It creates the spark that ignites the air-fuel mixture, and its design has a significant impact on engine performance, fuel economy, and emissions. The two most important factors to consider when choosing a spark plug are its heat range and electrode material.

Heat range refers to the spark plug's ability to dissipate heat. A "cold" plug transfers heat quickly, while a "hot" plug retains more heat. Using the wrong heat range can lead to pre-ignition (if the plug is too hot) or fouling (if the plug is too cold). For the 2017 F-350's 6.2L V8, the OEM-specified heat range is critical for optimal performance.

Electrode material also plays a key role. The center electrode, where the spark originates, can be made of several different materials:

• Iridium: The OEM plug for the 6.2L V8 is an iridium plug. Iridium is an extremely hard and durable precious metal, allowing for a very fine-wire center electrode. This creates a more focused spark, improving ignitability and extending the plug's life to 100,000 miles or more.
• Platinum: Platinum plugs offer a good balance of performance and longevity, typically lasting 60,000 to 100,000 miles. They are a popular aftermarket choice.
• Copper: Copper plugs have the largest-diameter electrode and the shortest lifespan (20,000 to 30,000 miles). However, they are also the least expensive and are a good choice for older vehicles with less-demanding ignition systems.

How to gap a spark plug

All spark plugs come pre-gapped from the factory, but it's always a good idea to check the gap before installation. The gap is the distance between the center and ground electrodes, and it must be set to the manufacturer's specification to ensure a strong, consistent spark. For the 2017 F-350's 6.2L V8, the gap should be between 0.041 and 0.047 inches (1.0 to 1.2 mm).

To check and adjust the gap, you'll need a spark plug gauge. This tool has a series of wires or feeler gauges of different thicknesses. Simply insert the appropriate gauge into the gap. If it fits snugly, the gap is correct. If it's too loose or too tight, you'll need to adjust the gap by gently bending the ground electrode with the tool on the gapper. Be very careful when doing this, as too much force can break the electrode.

Replacement procedure tips

The 2017 F-350's 6.2L V8 uses a coil-on-plug (COP) ignition system. This means that each spark plug has its own ignition coil mounted directly on top of it. This design provides a hotter, more efficient spark, but it also requires a few extra steps during plug replacement.

1. Coil-on-plug removal: Before you can access the spark plugs, you'll need to remove the ignition coils. Each coil is held in place by a single bolt. Once the bolt is removed, the coil can be gently twisted and pulled straight up to remove it from the spark plug.
2. The anti-seize debate: There is some debate among technicians about whether to use anti-seize compound on spark plug threads. The concern is that anti-seize can act as a lubricant, causing you to over-torque the plugs. However, many technicians still recommend using a small amount of anti-seize to prevent the plugs from seizing in the cylinder head, especially in aluminum heads like those on the 6.2L V8. If you do use anti-seize, be sure to reduce the torque by about 10% to compensate.
3. Dielectric grease: It's always a good idea to apply a small amount of dielectric grease to the inside of the spark plug boot before reinstalling the ignition coil. This will help to seal out moisture and prevent corrosion, ensuring a good electrical connection.

Known issues

While Ford has had issues with two-piece spark plugs breaking off in the cylinder head on some of its earlier 3-valve Triton engines, this is not a concern for the 2017 F-350's 6.2L V8. This engine uses a traditional one-piece spark plug design, which is much less prone to breakage.

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