Diagnostics of the engine on 2101-2107 by improvised means

I would like to say a few words about self-diagnosis and engine check on the VAZ 2101-2107. Since all “classic” motors are the same, there will be no difference. I will show everything using the example of my “Penny”, which I recently bought for disassembly.

So, I got the car not on the move. The previous owner said that one valve had burned out, but in fact it turned out that everything was fine with the valves there, but there was trouble with the camshaft itself, since its body was broken decently and pieces of it were lying under the valve cover, and the rocker also came off ...

After the camshaft was replaced with a new one along with the rockers, the engine began to work more or less normally, there was no knocking, but still far from ideal. Below I will tell you about those methods of self-diagnosis that you can use yourself without outside help:

Checking the exhaust pipe for oil contamination

If you find oil on the exhaust pipe, or a very strong deposit - soot, then this may indicate increased oil consumption, which in turn confirms the fact that the VAZ 2101 piston internal combustion engine is already quite worn out. First of all, you should pay attention to the piston rings.

Checking for smoke from the breather

Breather - a hole in the cylinder block, from where a thick hose exits and goes to the air filter. It is necessary to disconnect the end of the hose from the air housing and, with the engine running hot, see if smoke is coming from there. If such a fact takes place, then you can be sure that piston repair is just around the corner, you need to disassemble and repair the motor. Change rings, and perhaps even bore cylinders and change pistons.

Checking the compression in the engine cylinders

Here, improvised means cannot be dispensed with, and to check the compression in cylinders 2101-2107, you will need a device called a compressometer. To perform this kind of diagnostics, I specially bought such a device. In the photo below you can look at it:

1. This device has both a flexible hose with threaded fittings and a rigid tube with a rubber tip.
2. Includes non-fittings with two thread sizes

Compression test procedure

The first step is to blow off all the fuel by first disconnecting the fuel hose just behind the fuel filter. Then we Unscrew all the spark plugs:

After that, we screw the fitting of the device into the hole of the first cylinder, squeeze the accelerator pedal completely and turn the starter until the arrow of the compressor stops going up. This will be the maximum value for this cylinder.

We carry out a similar procedure with the remaining 3 cylinders. If, as a result of the diagnostics, it turned out that the difference between the cylinders is more than 1 atm., This indicates a problem with the piston group or with the gas distribution mechanism.

On the personal example of my 21011, the device showed about 8 atmospheres in each cylinder, which naturally indicates that the rings are already very worn out, since an indicator of at least 10 bar (atmospheres) is considered normal.

Checking the crankshaft for wear

In most cases, with a normal VAZ 2101 crankshaft, the light on the instrument panel, which is responsible for the emergency oil pressure, should not light up and flash when the engine is fully warmed up. If it starts to wink and even light up when the engine is warm, then this indicates that you need to change the liners or sharpen the crankshaft.