The advantage of the chain drive of the gas distribution mechanism is the lack of need for regular replacement of belt and rollers. The need to replace the chain occurs at a distance of not less than 200,000 km. When this mileage is reached or when the purchase of a new car is not purchased, it is desirable to check the wear of the chain by a special instrument.
If you are replacing a chain, you should also change the asterisks (similar to the belts and rollers). The whole chain needs to be changed only to a new one.
It is possible to independently determine the wear of the chain by removing the side cover and looking at the tenor of the chain. The more he is put forward, the more wear it is. If the burden is almost complete, the chain changes. The details will require the chain itself, the two guides and a chain-of-the-chain.