Timing chain tensioner for your car

For adequate valve clearance A timing chain is used for configuring and synchronising valve clearance. It connects the camshaft with the crankshaft and synchronises the piston stroke movement with the valve closure. As an alternative for the timing chain, a timing belt is used in many cars. All other solutions for valve clearance nowadays are obsolete and no longer used; the vertical shaft, basically a torsion bar with two gear wheels, was, due to its torsion inclination never a reliable solution. Neither the technically simple spur gear wheels, connecting crank- and camshaft with a set of gear wheels were suitable for tasks getting more demanding all the time: being too heavy, too slow and too laborious, they did not stand a chance against the technically simple solution of the timing belt and timing chain. Where the light and easy-to-replace timing belt is susceptible to wear, the original idea behind the timing chain was to create a durable solution for valve clearance. This turned out to be an error. Nasty surprise at the premium manufacturer Generally, the timing chain is considered a more lasting alternative to the timing belt. Instead of a rubber belt with glass fibre reinforcement, a timing chain consists of solid steel. For premium manufacturers like Mercedes-Benz this was the preferable solution for a very long time, contributing to long service periods. Until far into the 1990ies mileage millionaires were common for the German flagship brand. Yet in the 2000-ies something extraordinary happened: engines broke down by the dozen after 60.000 km and had to be replaced for reasons of goodwill. A supplier of timing chains was identified as the cause: for the sake of cost management the lifetime periods of the press and stamping tools for the chain links were extended. Burrs in the chain links appeared unnoticed, gradually slicing through the connecting bolts. A chain is only as strong as its weakest link and consequently only one faulty part was enough to cause an entire chain to rupture. The supplier admitted the problem and presently, spare parts able to provide the original durability for a timing chain engine are being supplied again. Maintenance routine for timing chains The valve drive of a timing chain engine consists of both gear wheels on crank- and camshaft, the timing chain itself and the chain tensioner. The unit "chain tensioner / timing chain" serves to keep the chain at its designated tension at all times. If the timing chain is too slack, this might cause the chain to skip which could in the worst case lead to massive engine damage. If the unit exercises too much pressure, the wear occurs more quickly, leading to a shorter life span. For this reason the tensioner and chain unit are equipped with automatic tensioning. When a tensioner has reached the end of his tensioning capabilities, the chain starts to "ring". In that case it needs to be replaced as soon as possible. The life span of a valve clearance with timing chain is nowadays still determined at 150.000 km at minimum. No compromises on quality The quality of a chain tensioner / timing chain unit and all other parts of the valve clearance is not apparent at face value. As said earlier, minor production faults can lead to engine failure. The manufacturing of the tensioner and timing chain unit and all its parts requires profound quality control. This is a costly business, and many foreign manufacturers are tempted to economise for reasons of maximum profit. Premium manufacturers, however, are certified according to ISO 9001 as well as the car manufacturer's specifications. With the certification provided on the packaging or shown on the website you can rely on the quality of the manufactured chain tensioner / timing chain set. Costs for a timing chain replacement A timing chain is not a very expensive car part. For the mentioned premium model an excellent replacement set from a branded manufacturer is available for 300 euro. Price comparison will show that for the same model, products at half that price are on offer. We strongly recommend, however, for this critical car part not to run any risks of a cheap offer. The challenge is not its purchase, but its installation. A garage can't perform this repair including the spare part for less than 1500 euro (£1300). A DIY replacement of a timing chain and tensioner is only recommended on condition of the required skills and experience being available. With DIY tools this task should take approximately 6 hours.