If you are comparing a heat range 6 and a heat range 7 spark plug for the same engine, the direct answer is that the 6 is one step hotter and the 7 is one step colder. The 7 keeps the electrode tip roughly 70-100°C cool...

A spark plug gap that is too small produces a short, weak spark that cannot ignite the air-fuel mixture reliably. In ordinary driving this shows up as a rough idle, hesitation when you press the throttle, a measurable d...

Selecting the heat range of a spark plug is not a performance upgrade. It is a combustion tuning decision that affects engine reliability. The heat range controls how quickly the firing tip sheds heat into the cylinder ...

Picture a 2020 sedan with 65,000 miles. The engine still runs, but you notice a slight drop in fuel economy and the cold start takes two cranks instead of one. That is usually the first subtle sign that the spark plugs ...

A spark plug does one essential job: it generates a high-voltage arc that ignites the air-fuel mixture inside the combustion chamber. That explosion creates the pressure that pushes the piston downward and turns the cra...

Spark Plug Indexing: The Short Answer Spark plug indexing is the deliberate rotation of a spark plug so that the open side of its ground electrode points in a chosen direction inside the combustion chamber. You do not n...

Spark Plug Number Meaning: The Code on the Shell Is a Full Specification The letters and digits stamped on the side of a spark plug are not a serial number and not a random sales code. They form a compact engineering sp...

Laser Iridium vs Iridium IX: The Short Answer Standing in the auto parts aisle, two NGK iridium spark plugs look nearly identical. Both carry a fine iridium tip, both are designed for modern engines, and both are often ...

The Short Answer: What a Conventional Spark Plug Is and When It Is the Right Choice A conventional spark plug — also called a nickel-copper or copper-core plug — is the standard parts-catalog ignition component for engi...

The Main Spark Plug Families Modern engines generally run on five spark plug families: nickel-copper, single platinum, double platinum, single iridium, and double iridium. If you need a direct conclusion, iridium and do...

A spark plug wear chart tells you exactly one thing that matters most to an engine's health: how much of the electrode has eroded away and whether the gap has widened past the point where combustion stays reliable. As a...

Spark Plug Condition: The Direct Answer First A healthy spark plug condition shows a light tan or grayish-brown deposit on the insulator tip, a clean electrode with no excessive erosion, and a gap that matches the engin...