Major Spark Plug Brands Ranked Worst To Best
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Most manufacturers suggest spark plugs (and wires, if you're being thorough) be replaced between 30,000 and 100,000 miles depending on the vehicle and use case. Pulling a single plug is usually a straightforward process, as is inspecting the plug for things like corrosion, fouling, or oil. When replacing the plugs, manufacturers and technicians agree that the best practice is to do all of them at once, and check the gap on every plug.
Spark plugs, like oil changes or tire replacements, are one of those maintenance items that are easy to overlook, but can cost a driver in a number of ways, including reduced gas mileage, hard starting, and reduced overall engine performance. As for what brand to use, it's usually advised to stick with what the manufacturer suggests, or what originally was installed in the engine. However, if one isn't sure what that is, if the engine or plugs have been replaced, or if it's an older model, it can be better to use a reliable and well-known spark plug brand. What follows is a ranked list of the top major spark plug manufacturers.
Autowxjq
When searching for anything on Amazon, oftentimes a sponsored product will make its way to the top of one's search results. While it's often a similar item, there are some telltale signs that it's a knockoff or cheaper item than what one wanted in the first place. In this regard, spark plugs are no different from thousands of other products on Amazon. While there is no straightforward path to sorting search results by lowest customer review, one advertised spark plug brand repeatedly pops up during Amazon searches – Autowxjq. The unpronounceable brand of spark plugs only has one to three reviews per plug size, and the few reviews that aren't generic positives complain of premature plug fouling.
The listing itself has some red flags, as well. While a 4-pack of iridium plugs only costs $17, the ad copy is riddled with the kind of spelling errors and grammatical imperfections one expects from a poorly-translated website or product flier. And while replacing plugs can occasionally clear a check engine light resulting from a misfire, it's not a great look to claim "Perfecting Eliminating Engine Lights" without offering any information to back that claim up. Look, spark plugs aren't that expensive overall — move past the Autowxjq plugs.
Accel
Part of the larger Holley lineup of aftermarket brands, Accel is primarily marketed for racing applications or folks looking to upgrade classic vehicles. It promotes the benefits of copper spark plugs over longer-lasting iridium plugs, which makes sense when trying to wring every last advantage out of an engine by increasing power regardless of cost.
Accel's plugs feature design considerations that make its copper plugs some of the best available. A unique grounding design for the electrode allows for a more efficient and complete burn of the air-fuel mixture. When combined with a hotter spark and a larger flame on combustion, Accel's plugs make a good choice for drivers of older vehicles designed for use with copper plugs, or for drivers who don't mind replacing plugs often.
Amazon reviewers make a point of mentioning that the copper-core plugs that Accel specializes in will only last about half as long as one would expect from their platinum or iridium counterparts. Even so, several Accel plugs maintain an Amazon star rating over 4.5, and a lot of reviews mention the so-called "shorty" plugs as a godsend for older vehicles that need as much extra clearance between plug boots and manifold or headers. The little bit of extra room provided by a plug that's ⅜" shorter than a standard replacement can reduce the risk of burnt spark plug boots or dented headers, and for anyone who's gotten bloody knuckles during a tuneup, that's a great benefit that might have otherwise gone unnoticed.
Motorcraft
In 1961 Ford purchased the Electric Autolite Company, a manufacturer of Ford replacement parts. The company rebranded Autolite as Ford Motor Company's parts manufacturing arm, Motorcraft, in 1972. Motorcraft has been supplying the automaker, as well as its dealerships and mechanics around the world, with genuine Ford parts ever since.
As previously stated, the best replacement for a vehicle's spark plugs is typically the brand of plug that was in the engine to begin with. For Ford's vehicles, that would be Motorcraft. It's a similar situation to the replacement battery issue in vehicles — when a car is engineered with the specs of a certain part in mind, it only makes sense to maintain those specs.
Motorcraft backs its plugs with a two-year warranty that includes labor costs and unlimited mileage. Most of its offerings are platinum, iridium, or nickel plated, covering the full spectrum of requirements for its vehicles. Motorcraft also maintains a 4.7 Amazon star rating on their most popular offering on the site, and over 2,500 reviews make a strong case for the brand. They're great quality parts, are updated to evolving specs, and rarely fail prematurely.
AC Delco
Another manufacturer-backed parts company, AC Delco's spark plugs are well-regarded for the same reasons as Motorcraft — General Motors' engines are designed with AC Delco plug specs in mind.
AC Delco is a company born from United Motors Corporation (GM would change the name to United Delco around 1960) and AC Spark Plug, both parts companies that GM acquired over the years. Interestingly, the founder of AC Spark Plug was Albert Champion, a bicycle racer unable to use his own name on his company after leaving his first company, Champion.
As the genuine parts provider for General Motors, AC Delco manufactures OEM plugs for a vast number of makes and models, from the Cadillac Escalade to the GMC Sierra. And while Amazon lists a number of plug sizes, the fact that GM has its own online store does throttle the number of ratings. Even so, most of the plugs listed maintain over 4.5 stars, no small task in the world of Amazon ratings.
Autolite
The first Autolite spark plug was made in Ohio in 1936, the result of a year of development involving an eager ceramic engineer, a group of draftsmen and staff, and the backing of the Electric Autolite Company. Since then, over 10 billion spark plugs have been produced by Autolite, which is now a part of the larger FRAM Group. In the past, Autolite supplied OEM plugs to Chrysler, Willys, Studebaker, and Packard.
These days, Autolite is primarily known as an aftermarket spark plug company, manufacturing plugs for everything from race cars to riding mowers. Its products are carried in nearly every large auto parts chain in the country, including NAPA, AutoZone, and O'Reilly. Autolite also sponsors a number of professional racing and motorsports teams.
Online, Autolite plugs are some of the best-rated and reviewed around, with the Autolite Amazon store carrying convenient and low-cost four packs of many plug sizes and types including the popular Iridium XP, which boasts 4.6 stars among over 1,700 reviews. Those plugs feature an iridium center wire and a platinum-protected ground wire and claim a service life of up to 100,000 miles.
E3 Spark Plugs
E3 spark plugs are a relative newcomer to the scene, with the company having been founded in 1997 – but one with a completely different approach to plug design. When other plug makers looked to specialized metals like platinum and iridium, E3 decided to redesign the spark plug itself, specifically the "J-wire" electrode, to improve the ignition of raw fuel inside the engine, minimizing greenhouse gas emissions. The result of that research is the patented DiamondFire ground electrode, a three-legged, almost spade-shaped ground that E3 claims improves spark energy and heat transfer.
While many of its products are designed with high-performance applications like motorsports in mind, E3 has also taken what it's learned from those intense uses and applied that to its automotive and motorcycle spark plugs.
A focus on online sales has driven the young company to fast success. E3 plugs are carried on nearly every automotive parts and supply store on the internet, and reviews are high on both their own testimonials page and on Amazon, where its best-selling automotive spark plugs maintain a 4.5-star rating among over 1,500 reviewers.
DENSO
Another OEM supplier is DENSO, which is the parts manufacturer for Toyota. DENSO has been around since 1949, when it branched off from Toyota itself, and the company has an interesting relationship to another spark plug brand. Back in 1953, DENSO entered a "technical assistance agreement" with Robert Bosch, the founder of the now-global aftermarket parts (and spark plug) company. That partnership ended after two years, and by 1957, DENSO had taken what it learned from Bosch and started its own spark plug lab.
Since then, the company has become one of the best-known spark plug brands, and one of the most innovative. Some of its inspired (and quickly patented) ideas include a "wide U" grooved plug and the introduction of platinum and iridium elements to its spark plugs.
DENSO plugs today continues that trend of innovation in both its OEM and aftermarket offerings, using a combination of materials that it has introduced in past designs. The TT plug, for example, utilizes a platinum center, a titanium-enhanced ground, an alumina power insulator, and a copper/glass seal bonding the electrode to the insulator. That dedication to improving its product has led to great reviews online, with DENSO's best-reviewed spark plug boasting a 4.7-star average on Amazon among over 1,100 ratings.
Champion
Albert Champion was a French bicycle racer who also ran motorcycles and the occasional automobile. After a crash in 1903 left him hospitalized, Champion spent his recovery learning about automotive mechanics. That new knowledge sparked the establishment of the Champion Ignition Company, and Champion is widely credited with bringing the spark plug to the masses (although not inventing it outright — that's a whole other debate). His plugs used a ceramic insulator to keep the electrode protected from outside elements and from grounding.
When Champion was lured to General Motors in 1908, legal issues led him to use his initials for his new venture — thus, AC Spark Plugs was born. That left Champion Ignition to continue marketing its product under its founder's name.
Champion went on to become a leader in the industry, with its plugs being used in the Ford Model T in 1908 and the Le Mans winning team in 1978. Its current product line includes iridium, platinum, double platinum, and copper options — all reliable, reasonably priced, and branded with one of the best-known logos in automotive parts. Champion's presence on Amazon features spark plugs with a 4.7-star rating and an impressive 8,800-plus reviews, with 81% of those 5 stars. The company's history and reputation truly make it one of the best in the industry.
Bosch
Bosch is a German company founded in 1886 by Robert Bosch, a man with a dream and a better design for automotive ignition. He got his start in a workshop that employed himself, a journeyman, and an errand boy; over 130 years later, Bosch is now a multinational manufacturer that makes everything from power tools to security cameras to automotive parts.
Those auto parts include some of the best spark plugs in the aftermarket, with special designs that focus on improving upon OEM plug design. Double iridium plugs provide four times the service life of copper plugs, while EVO spark plugs were created with turbocharged gasoline direct injection engines in mind. There's even a unique four-ground platinum option, which is said to improve fuel economy and engine performance.
Bosch's reputation as a manufacturer of quality spark plugs — a business the company has been in since 1902 — is evident in its Amazon ratings. Its Double Platinum plugs maintain a 4.5-star rating with over 3,200 reviews. High review scores on many of its other plugs and, indeed, on many of their other aftermarket parts, in general, make Bosch a great option for a replacement plug if the OEM part isn't readily accessible or just hasn't served the driver well in the past.
NGK
The original equipment standard for nearly every Japanese automaker, NGK produces simply the best spark plug brand for both OEM applications as well as general plug replacement and racing use. This claim is supported by a shocking list of over 1,000 different types of spark plugs for virtually any engine.
NGK (now technically Niterra, but keeping the NGK brand to avoid confusion) is a brand with a reputation so stellar it has been accused of overengineering its product. In reality, it has simply put an incredible amount of focus on developing and improving its spark plugs. Those plugs are used in both the everyday applications NGK is known for as well as in the motorsports vehicles it sponsors.
On Amazon, several of the manufacturers feature one or two spark plugs with a large number of ratings and reviews. NGK blows these others out of the water with multiple plugs with over 1,000 ratings, including this variety of the G-Power spark plug with over 7,200 reviews. In short, given its widespread support from both technicians, engineers, and manufacturers, NGK spark plugs are likely what you'll be removing from an engine — regardless of the application or manufacturer — and definitely the top choice for what to put back in.