Sparesbox Blog

Why One Size of Spark Plug Does NOT Fit All!

By Brad Nash

Fri Feb 26 2016

Many spark plug suppliers will tell you that one spark plug will fit a number of vehicles. What they don’t tell you is that this “one size fits all” approach compromises the performance of the vehicle. This old-school type of thinking disregards advancements in modern engine evolution and can compromise precision engine output, reliability, and fuel efficiency.


But Why?

Engine manufacturers spend many years researching and developing a new engine blueprint. During this complex process, every engine component, including the spark plug, is engineered and tailored to perfectly match the make and model to ensure optimum performance and durability.

When Spark Plugs are commonised, important attributes are ignored that can have a big effect on performance and longevity. Some key side effects include:

Heat Range

Spark Plug Heat Range


  • Too cold – Spark Plug is prone to carbon fouling
  • Too hot – Spark Plug is prone to detonation/pinging – that can escalate to overheating damage of the engine


Centre Electrode Projection

Spark Plug Center Electrode Projection

  • Too long – High risk of mechanical interference with pistons or valves
  • Too short – Reduces ignitability, performance and fuel efficiency


Number of ground electrodes

NGK Spark Plugs

  • Replacing the multi-ground OE spark plug design with a single ground electrode Spark Plug, can cause unstable idle for wasted spark ignition systems


Ground electrode design
  • Adverse effect to ignitability, performance and fuel efficiency


Double Fine Electrode (DFE) design
  • By replacing a non-DFE OE spark plug design with a DFE Spark Plug, can create issues stemming from excessive ground electrode projection and inefficient heat dissipation.


NGK Spark Plug Australia are engine ignition specialists, partnering with OE engine manufacturers to ensure all NGK Spark Plugs meet exacting engine specific requirements. As a result, every vehicle is perfectly matched to its make and model for optimum performance.

In addition to our expansive lines of NGK Spark Plugs, we also offer a selection of Champion Spark Plugs, Bosch Spark Plugs, and many more!