Chain maintenance and when to change?
The timing chain can be replaced at one of the service centers, but here we will talk about how to carry out this procedure with your own hands. The manufacturer has not outlined the exact regulations for replacing the chain on this car, but from the recommendations of experts we can conclude that it is necessary to inspect the chain after 100,000 km. If you do not do this, you may miss the moment when the chain may come off. And if this happens, the valves will hit the pistons, since the synchronization of their movement will stop. After this, the car will have to undergo serious repairs, so it is better not to let this happen.
Chain wear can be determined by ear - in this case, the switched on motor will make a characteristic grinding noise. Visual signs of wear may include the following:
- chips have formed on the chain;
- if the chain is pulled back by half a tooth;
- the pitch between the links is increased;
- The marks on the crankshaft housing and pulley no longer line up.
Even with normal compression, the engine will not work smoothly if the chain is stretched. It will no longer be possible to correct this condition of hers, and in this case she will have to be changed. Oscillations of a loose drive can lead to damage to the dampers. A stretched chain drive will cause excessive fuel consumption and the engine will vibrate. Already one of these reasons will be enough to replace the worn chain with a new one.
It must be said that some other parts that are consumables will also have to be changed. We are talking about oil seals and gears. The chain puts a lot of stress on the gears, and they wear out quite quickly. Therefore, it is better to install new gears, so as not to have to disassemble the entire mechanism due to the replacement of gears. But it is not always necessary to change them. It is better to visually assess their condition before making a decision. If you don’t have much confidence in yourself, then call a specialist who can diagnose the condition of the gears. This is very important, because if heavily worn gears are not replaced, they will have a negative effect on the new chain, and it will wear out much earlier than expected.
When buying a new chain, do not save money, and buy consumables only from trusted manufacturers and in serious retail outlets. Along with the chain, also buy oil seals, gears (if necessary), gaskets and plastic stabilizers. Prepare the tools necessary for such repairs and you can get to work.
Replacing the chain drive yourself
1. Place the car on a level surface and turn off the power by disconnecting the battery terminal. 2. Now you need to remove the air filter and install the plug on the carburetor neck. 3. Disconnect all wires and hoses from the air damper. To prevent them from interfering with further work, they must be taken to the side. 4. Now we need to remove the generator belt and pump pulley. 5. For free maneuver, remove the crankcase protection. 6. Remove the belt of additional units, having previously dismantled the drive system housing. When removing the drive, it is necessary to mark the direction of its movement. If this is not done, then it will also function, but its teeth will wear down prematurely. 7. Drain the antifreeze. 8. Now you can start removing the timing chain. This can be done manually or using a special device. With a device, of course, it’s easier and faster, but if you don’t have it, you’ll have to make do on your own. 9. Using a locking bolt, fix the crankshaft. 10. There is a plug on the block near the crankshaft pulley. It needs to be unscrewed. A locking bolt is installed in its place. The bolt must be screwed in all the way. If this does not work, turn the crankshaft 90 degrees to the right and try again. This must be repeated until the bolt is screwed in exactly until it stops. Now turn the crankshaft to the right until it is completely blocked. 11. Remove the pan. If there are oil leaks, we draw conclusions about replacing the seals. 12. Drain the engine oil and change the gasket between the catalyst and the pipe. We do not save the oil, as we will be filling in new oil. 13. Using a rubber hammer, remove the pan and clean it of oil leaks and traces of sealant. 14. To make the chain accessible, it is necessary to dismantle the attachments. Remove the housing cover.
15. Remove the tensioner and the oil supply pump. 16. Dismantle the camshaft gear, having first unscrewed the bolt securing it. After this, the chain itself and its guides are removed. 17. Before you start installing a new consumable, you need to check its contents. 18. Now all the parts are installed in the reverse order, after which the tensioner is installed.
19. Do not rush to immediately install the covers in their places. First you need to check their seats; they are thoroughly cleaned of dirt, after which a thin layer of sealant is applied to them. When 5 minutes have passed after applying the sealant, you can install the casing. It is not recommended to do this earlier, as the sealant must harden. Do not apply too much material, as this may cause it to penetrate inside. Its deficiency can lead to leakage. 20. Now you need to check the progress of the work. To do this, start the engine and listen to how it works. If everything is done correctly, the sound will be familiar, producing a pleasant rustling sound. If something is done wrong, a rattling sound will be heard.
Chain tensioner video
Repair and comprehensive maintenance of Mercedes-Benz engines
The four-cylinder Mercedes M271 engine has excellent technical characteristics despite its small volume.
Structurally, the M271 engine comes in two modifications - with injection into the intake manifold (M271 KE) and direct injection into the combustion chamber (M271 DE). In addition, KE engines are equipped with a COMPRESSOR CHARGING system, and engines with the DE index are equipped with TURBO CHARGING.
Both engine modifications KE and DE, having high output with a small engine volume (1.8 liters), are not without operational drawbacks. The main problems with the M271 are the TIMING CHAIN and SPRINGS.
Timing marks 271 Mercedes motor
Mercedes-Benz uses a chain to drive the engine timing mechanism.
Typically, the timing chain resource is at least 100 thousand kilometers of the vehicle. When using high-quality oil, timely replacement of the last engine and careful operation of the engine (gentle mode), the life of the timing chain can be twice as long. Quite often on the 271 engine there is a factory defect in the mechanism for changing the position of the intake camshaft. However, mileage may vary.
The defect manifests itself with the following symptoms: knocking in the front part of the engine when starting, problematic engine starting (does not catch), when the position of the camshafts no longer corresponds to the specified values, the CHECK ENGINE warning light comes on.
Continued operation of the Mercedes with this malfunction will lead to the timing chain “jumping” and a major engine overhaul may be required.
Timely replacement of the chain and camshaft position adjustment mechanisms (when the first symptoms appear) is much cheaper than eliminating the consequences.
When replacing the timing chain - on the 271 engine (in-line 4-cylinder gasoline engines), the chain is replaced using the pulling method. During such work, the engine is not dismantled, but remains in its place in the engine compartment. Only the cylinder head cover (valve cover) is dismantled.
The chain and mechanisms for adjusting the position of the intake and exhaust camshafts are being replaced. The timing chain tensioner, gaskets, and antifreeze must also be replaced as necessary.
Auto service center POSITION 2000 will replace the timing chain and camshaft adjustment mechanisms of the M 271 engine within one working day.
Valve cover removed
Front timing case cover
Old mechanisms and chain, mileage 60 thousand km. on original MB oil
Old mechanisms, tensioner, chain, dampers
Complete set of spare parts for chain replacement
New mechanisms and chain installed on the engine
On the Mercedes M271, a chain is used to drive the timing mechanism. Of course, it has certain advantages over the belt drive used in other brands of cars, but it too must be replaced over time. The advantages of the chain include the fact that, unlike a belt, it does not break, but it may well stretch, which will also bring a lot of inconvenience to the car enthusiast. With a stretched chain, the pitch between the links increases, and it can fly off the sprockets. And this will not be much different from a broken belt drive. Here we can no longer do without replacement. It is about replacing the chain drive on a Mercedes that we will talk here.
M271 Engine Problems
The problems of the M271 have been known for a long time; the long single-row chain, which ensures the rotation of the motor shafts, is subject to stretching under high loads. In addition, the problem area of this engine is the timing star mechanisms. Stars (couplings) are characterized by wear of the working surface (teeth) and destruction of the internal mechanism.
Chain stretching is accompanied by uneven engine operation and a noisy start with a metallic sound. Starting the engine takes much longer than with a working engine. Crackling and knocking noises characteristic of diesel engines may be observed.
- A stretched chain on the M271 can break or jump over the teeth of the timing sprockets, which leads to bent valves and subsequent major repairs.
- Wear on the surface of the timing stars can also lead to the timing chain skipping, breaking and, as a consequence, bending of the valves.
- Malfunction of the internal mechanisms of the timing stars on the M271 engine leads to the appearance of extraneous sounds, incorrect operation of the injection system, fuel injection phases - the engine may run unevenly, coking of the spark plugs is observed, the engine operates noisier with knocking and crackling noises, troits both cold and hot .
- Another problem with the M271 is oil filter leakage. This usually happens during the cold season. A leak can cause a low oil level in the engine, and if this moment is missed, the consequences for the engine can be dire - even leading to major repairs.
- The quality of the oil determines the life of the engine;
- Scheduled oil changes can increase engine life;
- It is advisable to update the engine software;
- When the first symptoms of a malfunction appear, repairs should not be delayed;
- The motor must not overheat, which will have a detrimental effect on the circuit;
- It is recommended to use high-quality motor oil (original with viscosity 5W-40).
Mercedes-Benz C-class “Alabaster” › Logbook › Replacing the m271 timing chain
Most owners of Mercedes from the early and mid-2000s are probably aware of the features of the m271 engine. Namely, that the timing drive has a single-row chain, which tends to stretch. The chain resource according to various sources is from 60 to 80 thousand km. And also, the so-called “stars” of the phase regulator, which, when the chain is stretched, wear out and the chain jumps, the pistons meet the valves, repairs cost 150+ thousand rubles. with stories to everyone I know about how expensive and expensive Mercedes is.
But despite this, there are rare cases when the chain runs for 150-250 thousand km, and the “stars” of the phase shifters are original at about 350 thousand km. But these cases are very rare, and somehow I didn’t want to conduct such “experiments” with my car.
The previous owner assured that he changed the chain 20 or 30 thousand km ago, but you can say anything, they didn’t look at it when buying it, and I’ve driven almost 60 thousand km since I bought the car. Of course, you can understand that it’s time to change the chain by the characteristic sound, but it seems to me that if the noise of the chain is heard, then it’s worth changing not just the chain, but also the “stars”, and they cost if the original is not at all cheap.
Having chosen the time, I went to a friend to replace the chain. He himself drove a w211 with the same engine, was well acquainted with the process of replacing the chain, worked in a Mercedes service center, and had a special tool for fixing the shafts, but despite all this, it took about 4-6 hours.
I changed the chain by pulling, riveted the chain, attached a new one, tied a wire to the other end of the old chain and in this way pulled the chain completely and riveted it. It is advisable to perform this procedure with four hands, because The chain needs to be constantly tensioned.
I only replaced the chain and the guide bar on top (26), there was obvious wear, as well as the deflection roller. I didn’t buy the video, but he happened to have this video in stock, which he gave away for free. I also didn’t replace the chain tensioner and guide bars, I said that the next time I replace them I’ll have to change them, now there’s no point. I trusted his experience.
The old chain, in comparison with the new one, stretched by about a link; the “stars,” as he said, were in good condition.
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