It’s a challenge which has resulted in bespoke components for a parc which is more niche than ever before.
As such, like many components, the spark and glow plug market is becoming increasingly driven by original equipment suppliers.
As carmakers move towards bespoke fitments for their new vehicles, the pressure grows for spark plug manufacturers to get the standard fit.
There are big benefits for plug manufacturers working with carmakers.
However, the many different fitments can cause stocking issues for workshops, according to Mike Parsons, of Unipart.
“Workshops would once hold spark plugs as a stock item,” he says.
“Given the higher costs associated with new plug technology and the increased range required, they would be wise to consider moving towards an on-demand approach.”
To solve the problem, some spark plug manufacturers are moving towards a shorter range for the aftermarket.
Bosch and Champion both reduced their range to around 50 fitments last year, claiming this would allow garages to stock plugs for around 90% of vehicles.
But others argue that shared fitments will lead to vehicles being fitted with plugs that don’t meet factory specification.
Brian Childs, deputy managing director of NGK, says: “The aftermarket has changed in the last few years due to OEM presence, and many have a shortened range.
We supply the same as OEM specification; we’re offering the end user the same as should be fitted.”
Even those who have taken this route admit that the trend towards bespoke fitments may cause them to rethink.
#AM_ART_SPLIT#Michael Hoade, of Bosch, says the range is aimed at older vehicles, and that the next few years will force it to expand its range.
Environmental pressures have led to more expensive metals, such as iridium, being used.
These are aimed at lengthening the plug’s life and ensuring it maintains its gap and thus efficiency for a longer period.
Spark plugs are now almost fit and forget. In some cases, a car may only have one new set in its lifetime.
But despite a 5% drop in volume, the higher price of raw materials and widespread use of more expensive metals has pushed up prices by 10%.
Increasing diesel popularity has also had a major effect.
In the UK, these represent 18% of the parc, but higher fuel prices and emissions-based road tax is causing this segment to grow.
Frank Toebes, of Denso, claims the European glow plug market will reach 41 million units by 2010, a 75% increase on 2004.
In some European countries Denso is getting more revenue from glow plugs than spark plugs.
These present new issues for workshops.
Sales of glow plugs vary seasonally, peaking during cold months.
And, because glow plugs are often specified to last the lifetime of the vehicle, rising diesel penetration will further reduce sales.
Increased plug life is also affecting engine design.
Less frequent changes makes it less important for vehicle manufacturers to make plugs easily accessible.
As a result, when the plugs are changed, this can involve higher labour charges.
The result is a stable market, with less frequent changes costing more for the consumer.
But with vehicles now potentially only coming into the workshop once or twice for new plugs, it’s essential that workshops can provide the right products at the right price to ensure that they get the work.