Spark Plugs at Easy Life Markets
Easy Life Markets sells spark plugs for petrol engines, listed with the thread size, reach, hex size, gap and electrode material you need to match the plug to your engine. A spark plug is the small part that lights the fuel and air in each cylinder, thousands of times a minute. Worn plugs cause misfires, hard starting, poor fuel economy and a rough idle.
To buy the right plug, check four things: thread diameter, thread reach, hex size and the gap your engine needs. Then choose the electrode material your engine was designed for. Our current range is small and starts with an iridium plug for Honda and Acura engines, and we will add more as the section grows. It sits within our electrical parts section of the main auto parts store.
What a Spark Plug Does
A petrol engine needs three things to run: fuel, air and a spark at the right moment. The ignition system supplies the spark. The ignition coil takes the 12 volts from the battery and steps it up to many thousands of volts. That high voltage travels to the plug, jumps the small gap between the centre electrode and the ground electrode, and lights the compressed mixture in the cylinder.
The plug also has a second job that is easy to forget. It carries heat away from the combustion chamber into the cylinder head. If it runs too hot, it can cause pre-ignition. If it runs too cold, it fouls with carbon. That balance is called the heat range, and it is one reason you should use the plug specified for your engine. The spark plug article on Wikipedia explains the construction and heat range in more depth.
Parts of a Spark Plug
- Terminal: the top connection where the coil boot or plug lead attaches.
- Insulator: the white ceramic body that keeps the high voltage from leaking to the engine.
- Hex: the six-sided metal section your plug socket grips.
- Thread: screws into the cylinder head. Its diameter and length must match the head.
- Seat: either a flat seat with a crush washer or a tapered seat with no washer.
- Centre electrode: the tip that carries the spark. Its material decides much of the plug's life.
- Ground electrode: the small arm the spark jumps to.
- Resistor: built into many modern plugs to cut radio and electronic interference.
Types of Spark Plugs by Electrode Material
The biggest difference between spark plugs is the metal used on the electrodes. Harder, rarer metals wear more slowly, so the plug lasts longer between changes.
Copper core plugs
Copper core plugs use a nickel alloy tip over a copper core. They conduct heat well and cost the least, but the tip wears faster, so they need changing more often. Many older engines were designed for them.
Platinum plugs
Platinum plugs have a platinum disc on the centre electrode, and double platinum plugs have one on the ground electrode as well. They last longer than copper plugs and suit many engines from the last few decades, especially those with wasted-spark ignition.
Iridium plugs
Iridium is very hard and has a high melting point, so iridium plugs can use a very fine centre electrode. A fine tip needs less voltage to spark and wears slowly. Many modern engines are designed for iridium plugs from the factory. The CR-V iridium spark plug in our range is an example, listed by the supplier as an iridium platinum resistor plug.
Which material should you choose?
For spark plugs, use the material your engine maker specifies, or a longer-life material in the same size and heat range where that is an accepted upgrade. Fitting copper plugs in an engine designed for iridium means more frequent changes and may affect running. Fitting iridium in an older engine designed for copper usually works, but it will not make the engine more powerful.
Spark Plug Comparison Table
| Type | Centre electrode | Typical life | Cost | Best for |
|---|---|---|---|---|
| Copper core | Nickel alloy over copper | Shortest | Lowest | Older engines designed for copper |
| Single platinum | Platinum disc | Longer | Medium | Many engines from the 1990s onward |
| Double platinum | Platinum on both electrodes | Longer | Medium | Wasted-spark ignition systems |
| Iridium | Fine iridium tip | Longest | Higher | Most modern petrol engines |
Service intervals vary a great deal between engines and plug types. Your vehicle handbook or service schedule gives the interval for your car, and that is the figure to follow.
Specifications to Check Before You Buy
Thread diameter
The most common sizes on car engines are 14 mm, 12 mm and 10 mm. A plug with the wrong thread will not fit, and forcing it damages the cylinder head. The CR-V plug in our range has a 14 mm thread.
Thread reach
Reach is the length of the threaded section. Too short and the spark sits back in the head and the engine runs poorly. Too long and the plug can hit the piston or valves. Our CR-V plug is listed with a 19 mm thread length.
Hex size
The hex decides which plug socket you need. Common sizes include 16 mm and 5/8 inch, and 14 mm on some newer engines. Our CR-V plug has a 16 mm hex.
Seat type
A flat seat uses a crush washer to seal. A tapered seat seals on its own cone. They are not interchangeable.
Gap
The gap is the distance between the electrodes. Engines are designed for a specific gap, and the plug should be set to it. Our CR-V plug is listed with a 1.1 mm gap. Fine-tip iridium and platinum plugs are usually supplied pre-gapped, and bending the ground electrode can damage the fine tip, so check the gap with care and avoid pressing on the centre electrode.
Heat range
Each plug maker uses its own heat range numbers. Use the heat range listed for your engine. Running a hotter or colder plug is only sensible for modified engines and is best left to specialists.
Resistor or non-resistor
Most modern cars need resistor plugs to protect their electronics from interference. Our CR-V plug is a resistor type.
Signs Your Plugs Need Changing
- Misfires, often felt as a stumble or shake under load.
- A flashing or steady check engine light with a misfire code.
- Hard starting, especially in cold or damp weather.
- Rough or uneven idle.
- Poor acceleration and hesitation.
- Fuel consumption creeping up.
- The service interval for your spark plugs has passed.
A misfire can also come from a failed coil, a cracked boot, a leaking injector or a vacuum leak. If one cylinder keeps misfiring after new plugs, swap that cylinder's coil with a neighbour and see if the misfire moves. If it does, the coil is at fault. Our ignition coil section covers that side of the system.
Reading an Old Spark Plug
The tip of a used plug tells you how the engine has been running. It is worth a look every time you change them.
| Appearance | What it usually means |
|---|---|
| Light tan or grey deposits | Normal running |
| Dry black soot | Rich mixture, a lot of idling or a weak spark |
| Wet, oily deposits | Oil entering the cylinder through worn rings, valve seals or a leaking seal |
| White, blistered insulator | Running too hot, possibly a lean mixture or wrong heat range |
| Worn, rounded electrode with a large gap | Plug is past its service life |
| Cracked insulator or broken electrode | Damage from detonation or careless fitting |
If one plug looks very different from the others, investigate that cylinder before you fit new parts. Heavy oil fouling is a sign of an engine problem that new plugs alone will not fix.
How to Change Spark Plugs
Changing plugs is one of the more approachable jobs for a home mechanic, as long as you work carefully. Some engines, such as V6 layouts, have rear plugs under the intake and are much harder to reach. If you are not confident, have a workshop do it.
- Work on a cold engine. Aluminium cylinder heads are easy to damage when hot.
- Disconnect the battery if your vehicle information recommends it.
- Remove the engine cover if fitted, then unplug and remove the coil or plug lead from one cylinder.
- Blow away dirt around the plug well so nothing falls into the cylinder.
- Remove the old plug with the correct plug socket and an extension.
- Check the new plug's gap and thread size against the old one.
- Start the new plug by hand for several turns to avoid cross-threading.
- Tighten it to the figure in your service information. Do not over-tighten.
- Refit the coil or lead firmly, then move on to the next cylinder.
Do one cylinder at a time so leads and connectors go back where they came from. Check coil boots for cracks or carbon tracks while they are off. A damaged boot can cause a misfire on a brand new plug.
Common Mistakes When Fitting Spark Plugs
Most problems after a plug change come from a few avoidable errors. Knowing them saves a lot of trouble.
- Cross-threading. Starting a plug with a wrench instead of by hand can strip the thread in the head. Always start by hand.
- Over-tightening. Too much force can stretch the plug shell, crack the insulator or damage the head thread. Use the figure in your service information and a torque wrench if you have one.
- Under-tightening. A loose plug does not seal or shed heat properly, and it can work loose.
- Wrong size or reach. Buying by appearance alone is risky. Compare the specification, not just the shape.
- Dropping the plug. A drop onto a hard floor can crack the insulator or close the gap. Check any dropped plug before fitting.
- Dirt in the plug well. Debris can fall into the cylinder when the old plug comes out. Clean the area first.
- Loose coil or lead. A boot that is not pushed fully home causes an instant misfire.
If you do not have the right plug socket and extension, our tools and equipment section is worth a look.
Spark Plugs on Engines With Leads
Older engines and some current ones use high-tension leads between a coil pack or distributor and each plug. On these engines, spark plugs and leads wear together. A lead with cracked insulation or a loose end can leak spark to the engine block, especially in damp weather. When you change the plugs, check each lead for cracks, burns and a firm fit at both ends. Damaged engine wiring and connectors can sometimes be replaced from our wiring harnesses range.
Storing Spare Plugs
Spare spark plugs keep well if you leave them in their packaging in a dry place. Do not store them loose in a toolbox where the tips can be knocked. Label the box with the vehicle they are for, so the right plugs go into the right engine next time.
Our Current Spark Plug Range
Our current range includes one plug, and we are honest about that. The CR-V iridium spark plug is a resistor-type plug with a 14 mm thread, 19 mm thread length, 16 mm hex and 1.1 mm gap. The supplier lists it for the Honda CR-V and Odyssey and the Acura MDX, RL and TL. It is sold as a single plug, so order one for each cylinder of your engine: four for a four-cylinder engine, six for a V6. Check the full product page for the details before you order.
We plan to add more plugs for other makes and engines. If you need a plug we do not list yet, please ask through our contact page.
Parts to Check at the Same Time
Plugs work as part of the ignition system, so it makes sense to check the parts around them. Coil-on-plug engines use a coil on top of each plug. In our ignition section you will find sets such as the Nissan ignition coil 4 pack, the MINI R56 coil pack of four, the GT-R coil pack of six and the single 07K905715F coil for Volkswagen and Audi. Older engines with a block coil and leads use parts like the UF277 coil pack.
Hard starting is not always ignition. A slow crank points to the battery or starters, and a weak battery can be checked with the BST100 battery tester from our batteries section. Running problems can also come from a faulty part in our engine sensors range.
Who This Section Suits
This section suits drivers due a routine plug change, home mechanics chasing a misfire, and owners who want to keep spare plugs on the shelf. If you own a Honda CR-V, Odyssey or one of the listed Acura models, our iridium plug is the first one to compare with your old plugs.
Buying Spark Plugs From Easy Life Markets
Each listing shows the thread, reach, hex and gap the supplier gives, with clear photos so you can compare with your old plug. The current price and availability are shown on each product page. For delivery information, see our shipping policy. Returns are covered by our return and refund policy, and general store questions are answered in our FAQ.
Frequently Asked Questions
How do I know which spark plug fits my car?
Match the thread diameter, reach, hex size, seat type and gap to your engine's specification or to the old plug. Then choose the electrode type and heat range listed for your engine.
Should I change all the plugs at once?
Yes. Plugs wear at a similar rate, and changing them as a set keeps every cylinder firing evenly.
Are iridium plugs worth the extra cost?
For engines designed for them, yes, because they last much longer. In an older engine designed for copper plugs, they mainly extend the change interval.
Do I need to gap a new plug?
Check it with a proper gap tool. Fine-tip plugs usually come pre-gapped, and forcing the electrode can damage the tip.
Can a bad plug damage my engine?
A misfiring plug wastes fuel and can overheat the catalytic converter over time. A broken plug tip can damage the piston or valves. Replace worn plugs promptly.
Why does my engine still misfire with new plugs?
The cause may be a coil, boot, lead, injector or vacuum leak. Swap coils between cylinders to see if the misfire moves, and read any fault codes.
How many plugs do I need?
One per cylinder on most engines. A few engines use two per cylinder, so check your vehicle information before ordering.