They may not look like much, given their humble size, but spark plugs are the heartbeat of a car’s engine. Without them, there’s no fire, no motion, no drive.

In most cars, there are four in number and are fully responsible for igniting the fuel-air mixture and sparking life into the engine, literally.

“Most motorists spend big on fuel and servicing, but ignore plugs until the car misfires, that’s when they come to us for diagnosis, and most often than not, the plugs are the culprits,” Julius Mwangagi, a Nairobi-based mechanic, told The Standard.

Each engine has a recommended type of plug to fit, and getting the wrong plugs could send you back to the garage sooner than you expect. This week on Motoring, we delve into the different types of plugs, their performance, and why they carry the weight of the whole engine’s performance, despite being tiny.

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Placement

Spark plugs are located on the top of an engine’s cylinder head, where they connect to either spark plug wires or coil packs, which then connect to each cylinder’s ignition system.

“They operate under extreme pressure and heat, and they can fire up to a thousand times in a minute. Their type, condition, and health are critical to the engine’s performance plus fuel economy,” Mwangangi warns.

Know your plugs

The automobile industry has undergone significant evolution, with the introduction of electric cars; hence, the days of a one-size-fits-all spark plug are now long gone. Today’s motorist has a range of options:

Copper

They remain affordable and highly conductive, and most garages recommend them for older or vintage/classic cars.

“They are a perfect fit for the older cars and can serve up to 3,000 kilometres. However, they are short-lived,” James Rubia, a mechanic on Mombasa Road, told the Motoring team.

Platinum

If one is looking for a good balance of price and performance, then the platinum plugs are the best option. They are known to last longer and can serve up to 120,000 kilometers with unmatched consistency.

The different types of plugs for different engines. 

Double platinum

Specifically built for modern waste-spark ignition systems. Durability is their strong suit.

“Waste-spark ignition system is where two spark plugs fire simultaneously through a single coil. During the process, one spark ignites the fuel-air mixture on the compression stroke, while the other fires during the exhaust stroke when no ignition is needed,” Rubia explained.

Iridium

These are the gold standard and are known to last up to 200,000 kilometres. Both mechanics concur that the iridium plugs offer better throttle response and improve the fuel efficiency of the engine.

“If you want to future-proof your car, iridium plugs are the way to go,” notes Peter Odhiambo, an electrical mechanic at Madaraka Auto Clinic in Nairobi.

Silver

A niche choice, used mainly in performance cars, high-revving engines, and motorcycles, thanks to their superior thermal conductivity. The silver plugs are renowned for their excellent thermal conductivity, as they transfer heat away from the firing tip more efficiently than other materials.

“You can find the silver plugs mostly fitted in Porsche Cayennes and Subarus for petrolheads. However, they wear out very fast since silver is a soft metal,” says Odhiambo.

Getting the right plug

Different manufacturers design ignition systems around specific plug types; hence, it is crucial to follow recommendations.

“Downgrading from iridium to copper in a modern engine is asking for trouble. You’ll see misfires, poor acceleration, and even damage to ignition coils,” Mwangagi warned.

On the other hand, upgrading to long-life plugs, such as iridium, in a car that originally used copper can be a smart move for drivers who want reliability with less frequent servicing.

When to change plugs

Spark plugs also have an expiry date, for lack of a better word. Below are some of the signs that your plugs are worn out and need to be replaced.

Misfires are causing the car to jerk while driving. Hesitation or sluggishness when accelerating or overtaking.

Rough idling

If you are visiting the pump stations more frequently than before.

All three mechanics engaged by The Standard agree that a timely change is one of the cheapest ways to avoid expensive engine repairs. “Spark plugs are the heart of combustion in the engine block. Treat them well, and your engine will reward you every time you turn the key,” Rubia summed up.

Without spark plugs, there’s no fire, no motion, no drive. Though tiny, they remain vital for performance and reliability.

Choosing the right type and replacing them on schedule can mean the difference between smooth, efficient motoring and costly garage visits.

Follow The Standard
channel
on WhatsApp

They may not look like much, given their humble size, but spark plugs are the heartbeat of a car’s engine. Without them, there’s no fire, no motion, no drive.

In most cars, there are four in number and are fully responsible for igniting the fuel-air mixture and sparking life into the engine, literally.

“Most motorists spend big on fuel and servicing, but ignore plugs until the car misfires, that’s when they come to us for diagnosis, and most often than not, the plugs are the culprits,” Julius Mwangagi, a Nairobi-based mechanic, told
The Standard.
Each engine has a recommended type of plug to fit, and getting the wrong plugs could send you back to the garage sooner than you expect. This week on Motoring, we delve into the different types of plugs, their performance, and why they carry the weight of the whole engine’s performance, despite being tiny.

Follow The Standard
channel
on WhatsApp

Placement
Spark plugs are located on the top of an engine’s cylinder head, where they connect to either spark plug wires or coil packs, which then connect to each cylinder’s ignition system.

“They operate under extreme pressure and heat, and they can fire up to a thousand times in a minute. Their type, condition, and health are critical to the engine’s performance plus fuel economy,” Mwangangi warns.

Know your plugs
The automobile industry has undergone significant evolution, with the introduction of electric cars; hence, the days of a one-size-fits-all spark plug are now long gone. Today’s motorist has a range of options:

Copper
They remain affordable and highly conductive, and most garages recommend them for older or vintage/classic cars.

“They are a perfect fit for the older cars and can serve up to 3,000 kilometres. However, they are short-lived,” James Rubia, a mechanic on Mombasa Road, told the Motoring team.

Platinum
If one is looking for a good balance of price and performance, then the platinum plugs are the best option. They are known to last longer and can serve up to 120,000 kilometers with unmatched consistency.

The different types of plugs for different engines. 
Double platinum

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Specifically built for modern waste-spark ignition systems. Durability is their strong suit.
“Waste-spark ignition system is where two spark plugs fire simultaneously through a single coil. During the process, one spark ignites the fuel-air mixture on the compression stroke, while the other fires during the exhaust stroke when no ignition is needed,” Rubia explained.

Iridium

These are the gold standard and are known to last up to 200,000 kilometres. Both mechanics concur that the iridium plugs offer better throttle response and improve the fuel efficiency of the engine.

“If you want to future-proof your car, iridium plugs are the way to go,” notes Peter Odhiambo, an electrical mechanic at Madaraka Auto Clinic in Nairobi.

Silver

A niche choice, used mainly in performance cars, high-revving engines, and motorcycles, thanks to their superior thermal conductivity. The silver plugs are renowned for their excellent thermal conductivity, as they transfer heat away from the firing tip more efficiently than other materials.

“You can find the silver plugs mostly fitted in Porsche Cayennes and Subarus for petrolheads. However, they wear out very fast since silver is a soft metal,” says Odhiambo.

Getting the right plug

Different manufacturers design ignition systems around specific plug types; hence, it is crucial to follow recommendations.

“Downgrading from iridium to copper in a modern engine is asking for trouble. You’ll see misfires, poor acceleration, and even damage to ignition coils,” Mwangagi warned.

On the other hand, upgrading to long-life plugs, such as iridium, in a car that originally used copper can be a smart move for drivers who want reliability with less frequent servicing.

When to change plugs

Spark plugs also have an expiry date, for lack of a better word. Below are some of the signs that your plugs are worn out and need to be replaced.

Misfires are causing the car to jerk while driving. Hesitation or sluggishness when accelerating or overtaking.

Rough idling

If you are visiting the pump stations more frequently than before.

All three mechanics engaged by
The Standard
agree that a timely change is one of the cheapest ways to avoid expensive engine repairs. “Spark plugs are the heart of combustion in the engine block. Treat them well, and your engine will reward you every time you turn the key,” Rubia summed up.

Without spark plugs, there’s no fire, no motion, no drive. Though tiny, they remain vital for performance and reliability.

Choosing the right type and replacing them on schedule can mean the difference between smooth, efficient motoring and costly garage visits.

Follow The Standard
channel
on WhatsApp

Published Date: 2025-08-29 11:50:00
Author:
By Mate Tongola
Source: The Standard
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