Extraneous knocking sounds appeared in the engine (VAZ-2101)

Valve knocking

If the car undergoes regular maintenance, this defect should not occur, since the clearances are always maintained within the norm. The main source of valve knocking is increased clearances between the levers and camshaft cams. High-quality clearance adjustment depends only on the performer. Such trifles as worn or deformed threads of the adjusting bolt, careless tightening of the lock nut will certainly become sources of clearance violation.

Sometimes there are more serious reasons that lead to valve knocking:

• increased wear of camshaft cams and rockers (levers);
• valve spring failure;
• wear of the bearing surfaces of the camshaft bearing housing.

If we refer to the plant's warranties, the service life of the camshafts is 70 thousand km. It is not uncommon for the shaft to serve 100-150 thousand km.

The camshaft, the cam-lever pair work almost in extreme conditions, since all engines installed on VAZ cars are high-speed. It is clear that any violation of the mode, no matter what it is, sharply affects the durability of the camshaft.

One of the main factors leading to rapid wear of the valve timing mechanism parts is low quality oil. If you fill the engine with low quality oil, you can be sure that it will not withstand the loads that arise in the friction zone. The oil film will be destroyed, and the rubbing pairs will find themselves in the most difficult conditions. Under such conditions, the temperature at the point of contact of two metal surfaces will almost instantly reach 900-950°C and, as a result, scuffing of the ground surfaces of the cam, and then its very intensive wear.



Similar phenomena occur if you forget to change the oil and air filters on time.

Why does the factory recommend changing the oil filter after 10 thousand km? Because its drain valve is designed for only 10 thousand km. It does not hold oil any longer. To fill such a filter with oil, the pump must work for at least 10 seconds, and during this time the engine parts will experience oil starvation. Approximately the same thing happens when the oil is dirty or when there is a suction of unfiltered air, etc.

The use of low-quality oil revealed additional reasons that contribute to the deterioration of the operating conditions of the rubbing surfaces.

Even if you follow all the manufacturer's recommendations, this does not mean that the camshaft of your car's engine will necessarily last a long time. It may happen that after 30-35 thousand km of mileage it will be necessary to change the camshaft and levers. Perplexed by this outcome, the most inquisitive car enthusiasts began to study this problem and determined that those shafts are subject to intensive wear, in which the hardness of the heat-treated layer is lower than required, that those cams are subject to progressive wear, in which the holes of the oil channels are located somewhat further from the tops of the cams than in the others.

In the course of the research, a number of proposals emerged that would allow the cams to operate in a more favorable mode. These included installing oil-deflecting screens in the camshaft housing, moving the oil channels, increasing the power of the oil pumps, etc.


The simplest method, suggested by a car enthusiast, is that the required cam lubrication regime is provided without increasing the oil supply to the camshaft channels. Simply, more oil is directed to the top of the cam.

This is ensured in the following way: from the edge of the hole 2 (Fig. 46) towards the cam, using an abrasive stone, a groove 1 in the form of a drop is selected. The oil flows along an artificially made channel (fading away) and is captured by the lever much more intensely than before and directed towards the top of the cam.



To determine the true condition of the cams and levers, it is enough to run your finger over their surface. Wear is clearly felt. The defect is confirmed by the difficulties you experience when you need to adjust the gaps between the cams and levers. A camshaft with worn cams must either be repaired or replaced with a new one along with the levers.

It is advisable to replace the camshaft, springs or camshaft bearing housing at a service station, since there are certain subtleties during assembly and, in addition, after installing new parts, it will be necessary to perform the already familiar set of operations: replace the oil and oil filter; adjust chain tension; set ignition timing; adjust the clearances between the levers and the camshaft cams.

For those who decide to replace the camshaft with levers or other parts of the gas distribution mechanism on their own, we remind you of the following: the surfaces of the camshaft bearing journals and the surfaces of the cams must be well polished and must not have any damage (traces of jams, scratches, steps, etc.). If, after inspection, you come to the conclusion that the camshaft can still serve, still check its radial runout. To do this, install the camshaft with its support journals (outer ones) on two prisms and measure the radial runout of the middle journals with an indicator. It should not exceed 0.02 mm. The gap between the camshaft journals and the supports in the housing should not be more than 0.2 mm. The internal supports of the housing surface should be the same as the support journals of the shaft, i.e. have no damage, including scratches. The camshaft pulley mounting bolt should be installed with a sealant.

If the wear on the camshaft cam does not exceed 1 mm, then you can leave it in place for some time. To determine the condition of the camshaft cams and levers, you must:

[The text is taken from the online resource VazBook.ru]

• remove the timing cover;
• turn the crankshaft using the starting handle or a special key for turning the engine crankshaft (vAZ-2105 and -2107 cars) until the marks on the gear and the camshaft housing are aligned;
• loosen the chain or belt tension;
• loosen the lock washer under the bolt securing the gear;
• make sure that the gear does not turn when you unscrew the bolt that secures it. The bolt should be unscrewed with a sharp movement;
• lightly tapping the inside of the gear, remove it together with the chain. It is advisable to temporarily fasten the gear and chain together to maintain their relative position. Lower the bundle of these parts down, allowing the gear to take up space between the damper and the shoe of the tensioner;
• loosen the nuts of the camshaft thrust flange, unscrew the nuts securing the bearing housing and carefully lift it together with the shaft;
• it is imperative to check the location of the housing centering bushings, which are often lost when the housing is dismantled;
• inspect the levers. Their working surfaces should be mirror-like. Only those levers that are worn out can be restored (risks, scratches, recesses) does not exceed 0.3 mm. If the wear is greater, such a lever is hopeless.

Removing lever 1 (Fig. 47) is not difficult. Pressing on its end resting on valve stem 7, turn it around adjusting bolt 3 and remove. Remember:

• where each of the removed levers was located, in order to return each of the levers to its place;
• that the surfaces of the levers in contact with the sphere of the adjusting bolt must be mirror-like. Any deviations (risks, chips) — a rejection sign;
• that the recesses on the ends of the valve stems should not exceed 0.5 mm. Such wear can be restored using a diamond file and polishing paste.

To work on the camshaft itself, it must first be removed from the housing. The back side of the cams will tell you about the quality of the clearance adjustment over the past period. If the surface has no marks, scratches or dark color, then the required clearances were provided. A back side polished to a shine is evidence of constant contact, i.e. a small clearance. If traces of friction are visible only at the edge, then the culprit is a lever installed at an angle. This happens when the lever spring is deformed. Remember that the ends of a free-lying spring should be in the same plane, and the distance between them should be 35 mm.

The most important operation is removing the unevenness of the contact surfaces of the cams and levers. The method and tool can be very diverse depending on your capabilities and abilities. Car enthusiasts use everything from grinding machines to needle files, bars and abrasive skins. It is important to grind and polish all the unevenness, removing the minimum possible surface hardened layer. Another condition for the effectiveness of the work done is the thorough cleaning of the repaired camshaft and levers from abrasive particles. To do this, it is enough to wash the parts in kerosene, gasoline and blow them with compressed air.

Installing the camshaft in place is a delicate and responsible operation. The assembly order is as follows:

• the camshaft, generously lubricated with engine oil, is carefully inserted into the housing in such a way that the thrust flange can be easily installed in the annular groove of the front journal;
• secure the thrust flange with two nuts;
• install the camshaft 5 (Fig. 48) so that the centering pin 3 and the hole 4 for the bolt in the end of the shaft are on the same axis with the technological hole 2 in the thrust flange 1;
• loosen the lock nut of the adjusting bolts and tighten the latter by 3-5 mm to avoid deformation of the valve stems when turning the crankshaft;
• clean, generously lubricated with engine oil levers together with springs are installed in their places, using the marks made during dismantling. Remember: the ends of the valves must be securely located in the grooves of the levers, and the springs must be installed without distortions;
• install the bearing housing onto the cylinder head studs and, strictly following the manufacturer's recommendations, tighten the nuts evenly, using a torque wrench without fail. The tightening torque should not exceed 22 N·m.

When installing the camshaft gear, do not apply any force. Place the gear on the shaft, making sure that the locking pin on the end of the camshaft enters its hole. Another hole on the gear is intended for the washer whisker located under the gear mounting bolt. When finally tightening the bolt, ensure that the gear does not turn.

When replacing the camshaft on car engines yourself VAZ-2105 and VAZ-2107 it should be remembered that the seal holder at the front end of the shaft should be installed on sealing mastic to prevent oil from penetrating into the area of the drive toothed belt and oiling it. If the mastic used by the plant is not available, paint that does not dissolve in oil can be used.

Another warning: Be careful when tightening the timing cover nuts. The shelf of this part is very fragile and does not tolerate force being applied to it.

After installing the camshaft with the housing and levers in place, it is necessary to perform such operations as tensioning the chain or timing belt and adjusting the gaps between the cams and levers.

Crankshaft knock

An unexpected knock in the engine causes concern for every car enthusiast, experienced or novice. First of all, it is necessary to figure out which engine mechanism is making the knock. The most convenient way to determine this is with a stethoscope. At the Chernigov Auto Parts Plant (gAZ branch) a special technical stethoscope has been developed that allows you to determine the condition of the engine and its units by ear based on the noise that occurs. To do this, it is enough to apply the acoustic probe to one or another unit. Some car enthusiasts successfully diagnose the engine with stethoscopes of their own making. An old oil can is soldered to a steel rod. To accurately determine the source of the noise, the end of the steel rod is alternately applied to different parts of the running engine, and the oil can is applied to the ear. Due to the fact that the thin bottom of the oil can is an excellent membrane, even the most insignificant sound will not be hidden from the ear.

The crankshaft knock is metallic and dull. Its frequency increases with the crankshaft rotation speed. If the axial clearance of the crankshaft is significantly larger than normal, the knock acquires a sharp tone with uneven intervals, especially noticeable during smooth acceleration and deceleration of the rotation speed.

The main reasons for crankshaft knocking:

• excessively early ignition. If this is the cause, then it is not a big deal. It is necessary to adjust the ignition timing, and the knocking should disappear;
• use of oil of a grade and quality that does not correspond to those recommended by the manufacturer. If the defect is not advanced, i.e. detected immediately after the knocking began, the situation can be corrected by draining the oil, flushing the system with cleaning oil and pouring fresh oil into the engine, as specified in the instructions;
• insufficient oil pressure. This causes malfunctions of the oil pump, pressure relief valve, clogging of the lubrication system channels. Considering that to correct the defects it is necessary to disassemble the engine (albeit partially), you shouldn't take on such work at home.

There are a number of other reasons that can cause crankshaft knocking: increased clearance between the journals and liners of the main bearings, misalignment and ovality of the main journals, increased clearance between the thrust half rings and the crankshaft, loosening of the flywheel-to-crankshaft mounting bolts. In all cases, engine disassembly is necessary, so the listed repairs should be performed at a service station.

Knocking of connecting rod bearings

Usually the knock of connecting rod bearings is sharper than the knock of main bearings. It can be heard at idle and with the gearshift lever in neutral. The knock increases with increasing crankshaft speed. To determine which of the four connecting rods is defective, one of the cylinders must be excluded from operation in turn by removing the high-voltage wire from the spark plug. The reasons that cause the knock of connecting rod bearings are very similar to the previous ones: incorrect ignition timing; low quality oil; large gaps between journals (now connecting rods) crankshaft and liners; ovality or taper of crankpins; non-parallelism of the axes of the upper and lower connecting rod heads. And again you have to go to a service station, since the engine will have to be disassembled.

Knocking of piston pins

The knock of piston pins is metallic and sharp. Many drivers often confuse this knock with detonation knock, but their nature is different. Unlike detonation, piston pin knock is better heard at idle speed. As a result of intensive wear of the pin or connecting rod head, the gaps increase, which causes the knock.

To eliminate the defect, the pins or connecting rods are replaced, but in both cases special equipment, a heating oven and a lot of skill are required.