Timing Belt Replacement and Routine Service


Timing Belt

Timing belts (Cambelts) & Timing Chains control the engine valve cycle sequence to ensure correct fuel combustion timing and compression.


Interference engine design allows pistons and valves to interfere or make contact if the timing sequence is not set correctly or if the timing belt snaps resulting in piston and valve damage requiring an engine rebuild with new pistons and valves.


Timing belts and chains should be replaced at the correct service intervals; especially on interference (most diesel) engines as belt wear causing incorrect timing may result in a very expensive repair bill.


Timing belt replacement involves synchronising valve and piston positions and setting the adjustable tensioning roller to ensure the belt is not overtightened putting additional strain on the camshaft bearings and crankshaft bearings correct adjustment of belt tension.


The lubricants, hydraulic fluids and anti-freeze chemicals used within the engine bay can degrade the rubber polymer compounds used in timing belt manufacture. As a consequence the belt life can be greatly reduced, especially if exposed to increased operating temperatures


Timing Belt Kits


The replacement parts needed for a timing belt service are usually supplied in "Kit"


Quality Timing Belt Replacement Kits usually contain:-






•Tensioner pulleys


•Tensioner Springs


•Cam Cover Gaskets



Timing Belt Fitting


Engines come in many variations: single overhead cam (OHC), double Overhead Cam (DOHC), overhead valve (OHV) and the engine timing-cam belt can be used to drive other essential components such as the water pump and fuel injection pump on diesel engines.


The belt can run a series of pullleys from three on a simpler OHC Engine to 8 on a performance V6, V8 Engine layout.


Timing belt fitting is a complex operation that requires a great deal of labour to do properly


It is worth ensuring that other components likely to suffer the same wear and tear as the timing belt and might require a major service or replacement before your next timing belt change are replace at the same time.


Maximise timing belt life and service intervals. Consider replacing the water pump if it's driven off the same belt, also the camshaft and crankshaft oil seals. If the camshaft oil seal or crankshaft oil seal fail then oil will impregnate the cam belt causing failure.


Water Pump Replacement


It's often worth changing the water pump when booking your car in for a replacement timing belt: Water pumps typically last for up to 100,000 miles so it makes sense to pay one labour cost rather than waiting for water pump failure or vehicle breakdown before fitting a new water pump



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