Best Spark Plugs in the UK

The Bosch FGR7DQP+ delivers deliver smooth acceleration, excellent fuel economy, as well as improved engine performance. Furthermore, the plug takes less time reaching self-cleaning temperatures, making its performance more responsive.

Made from platinum, the centre electrode tip comes outfitted with 4 yttrium-enhanced ground electrode tips. Creating a powerful spark, these enhanced tips enable efficient combustion, not just smoothing out the start but also making the engine's run more consistent. Because the plug is re-gapped, installation requires almost no time at all. Plus, the gap's indicated on the package, meaning that you won't be wasting time figuring out the required adjustment.

But the gasket that the plug comes with is not always tight initially, so we would not advise against tightening the plug up before installation. Circling back towards the platinum construction though, aside from protecting the plug against rust and corrosion, the material also makes sure the unit does not get brittle with time. The engineers at Bosch are so certain that the plug will remain unaffected that they have extended the warranty 7 years, so you won't be replacing this spark plug anytime soon.

Champion RCJ6Y Spark Plug champions an improved spark and reduced travel time from the spark to the combustion chamber. Not unlike the company's previous models, this plug is made from heavy-gauge, high-impact nickel alloy сentre electrode tip with a copper centre core, making sure that both the housing and the tip do not start displaying corrosion signs or forming rust patches eventually. Apart from that, the plug also resists fouling, but the biggest change that this construction makes is increasing the plug's conductivity and heat control, preventing the engine from wearing out before its time.

With its 9.5-millimetre thread reach, the model will be able to accommodate vintage cars, motorcycles, and garden equipment. That said, there are ATVs and boats that the plug will fit as well.

Setting machines aside, some chainsaws are also compatible with this plug but that's beside the point. The point is that, first and foremost, this plug gives you consistent cold starts and quick acceleration, making sure that even the least reliable engines behave well. Provided you don't mind the somewhat expensive price, there's almost no chance that the Champion RCJ6Y Spark Plug will leave you disappointed.

Despite its value-oriented disposition, the Briggs and Stratton 992304 can trade blows with the most expensive spark plugs. Having said that, we're not crazy about the centre electrode. From what we can tell, it is a little fragile. Nevertheless, again, this model can throw down with the best. 

Resisting carbon buildups as well as pre-ignition, the plug treats the engine with the care and respect that the car's heart deserves. Besides accelerating and smoothing out cold starting, the model makes sure that the overall run also remains smooth. Considering the 19-millimetre thread reach and its 19-millimetre hex size, this plug will prove compatible with most overhead valve engines (maybe even all). 

But the biggest standout feature has to be the NGK's patented triple-gasket sealing process anyway. In addition to eliminating combustion leakage, this sealing process also improves emissions and reduces exhaust fumes, making the engine a little more forgiving towards the environment. 

All things considered, the people whose commute involves countless stops and frequent speed shifting will appreciate the Briggs and Stratton 992304 the most. Also, the model will work with most garden equipment, including string trimmers, blowers, and lawn mowers.

As you would expect, the Champion RJ19LM Engine Spark Plug is not that different from its RCJ6Y stablemate. Primarily, the plug replaces the NGK BR2LM model that most lawn mowers, jet skis, and chainsaws come with from the factory. The similarities include the J-type gap that makes the model compatible with 9/10 petrol engines.

Of course, rubbing shoulders with the aforementioned plug, this unit has a 9.5-millimetre thread reach and a 19-millimetre hex size. With these specs, the model fits most pieces of garden equipment. The majority of motorcycles and ATVs work with these specs as well. The plug will not be able to suit modern cars but there are some vintage cars that can make it work.

Construction-wise, making the centre electrode tip from nickel alloy, this unit gives you a consistent spark without hiccups, so you should have no problems cold-starting the engine. In the meantime, the copper centre core will make sure that the plug does not overheat. Looking at the package, plug sometimes comes without a cardboard box, making things a little uncomfortable initially. Barring this little mishap, the Champion RJ19LM Engine Spark Plug will not inconvenience you short-term as well as long-term.

The NGK 4626 BPMR7A is the original piece that most petrol engines come from the factory. To start with, the plug adopts trivalent metal plating, not just protecting the unit from corrosion but also providing excellent anti-seizing properties. What's more, featuring corrugated ribs, the model prevents flashovers. But, before that, the plug introduces pure alumina silicate ceramic insulation, improving heat transferring and increasing its strength.

When this part is done, the copper centre core takes centre stage, aiding heat removal. Then, the plug unleashes its triple seal, preventing leaks. Leaving prevented leaks behind, the same seal also ensures reliable combustion, increasing the engine's lifespan.

The issue here is that, while the plug is working towards this increase, its own lifespan is pretty short, which's unfortunate and, truth be told, a little surprising considering that everything else about this product is first-class.

Nevertheless, taking into account everything that we have outlined above, as well as the plug reducing carbon deposits, the NGK 4626 BPMR7A is a force to be reckoned with, a force that very few engines will mind having by their side. Also, the nickel alloy centre will prevent the electrode tip from overheating.