Can changing the timing belt improve performance?
Updated 11 Oct 2019
In short, no, but let me explain.
The timing belt is a crucial component in the operation of your engine.
It keeps the camshafts and crankshaft operating in perfect unison, and needs to be changed at certain intervals set by the manufacturer to eliminate the risk of it breaking or wearing out.
It’s not uncommon to hear people say that their vehicle runs much better after having the timing belt replaced, but is there anything behind this theory?
Is it possible that changing the timing belt can increase performance? It’s time to get our detective hats on and find out!
First, a refresher on the timing belt system.
The timing belt is usually made out of a composite rubber material with high tensile fibres built in.
This allows it to run under high stress situations for long durations, keeping the crankshaft and camshaft timing in check.
The timing belt runs on pulleys, known as idler pulleys, and is kept under the correct tension via the timing belt tensioner.
The timing belt can also run the water pump, injection pump and the oil pump on some engines.
Now that we’re all on board with the timing belt system, let’s look at what components could increase the performance of the engine.
The two main components would be the timing belt tensioner and the timing belt itself.
Let’s investigate the tensioner first.
On some vehicles, the timing belt tension is controlled automatically via a hydraulic tensioner, while other vehicles rely on a manual tensioner set by the mechanic when the new belt is installed.
Both these components have a service life and if left too long without being replaced they can cause a decrease in engine performance as the engine moves slightly out of time.
This is more common with the manual tensioner as it cannot make adjustments for wear in the belt, as the hydraulic tensioner can.
Secondly, the timing belt itself may slowly wear away, mainly on the ‘teeth’ of the belt that grip onto the camshaft and crankshaft pulleys.
Over time, these points can wear away on the timing belt, leading to slight changes in the engine timing.
The only way to rectify this situation is to replace the timing belt.
So, as you can see, there are a number of components that can cause a REDUCTION in performance, which is actually the opposite to the original question - but they are both linked!
Over time, the performance may slowly drop off as these components operate through their service life and the engine falls more and more out of correct timing.
Replacing them with new components can give the false feeling of increased performance when the truth is the engine has just been returned to the correct state of operation.
No timing belt will give an increase in performance - it’s just not possible.
Its main job is to keep the timing in check.
Having your timing belt replaced and noticing an increase in performance is just a mix of the engine operating at peak efficiency and a good hit of placebo effect thrown in for good measure!
While you may be disappointed that, having changed the belt, you are not now able to leave your neighbours in a cloud of tyre smoke as you leave every set of traffic lights, it should be some comfort to know that a belt upgrade will have prevented an irritating, and potentially expensive-to-repair engine failure.
Finding a passion for cars from a young age, Joel carried out work experience as a mechanic whilst at school before starting an apprenticeship after finishing year 12.
After almost 10 years on the tools and in customer service, he moved into the IT realm as a Data Analyst and In-House mechanic at AutoGuru.