Note: To check if the valves are closing tightly enough, if the piston rings are worn or broken, or if there are other problems with the cylinders, it is necessary to measure the compression of all cylinders. For this to happen, the engine must be at operating temperature.
1. Unscrew the spark plugs.
2. Disconnect the ignition module
3. Open the throttle and starting air valves.
4. Insert the compression gauge into the hole of the first spark plug.
5. Ask your assistant to fully depress the gas pedal and turn on the starter.
6. Turn the crankshaft until the compression gauge shows the highest pressure.
7. Check the remaining cylinders in the same manner in order.
8. According to the rules, the compression pressure in any of the cylinders should not be less than 80% of the maximum measurement result. Low compression, uneven across the cylinders, can be caused by wear of the piston rings, which can also be detected by excessive oil consumption. With good compression the results should be at least 7.5 atm.
If the obtained values are close to or below the minimum values given, this indicates the need for an additional inspection of the engine:
The difference between the compression pressure values of individual cylinders should not be more than 1.0 bar.
Low compression pressure may be caused by worn piston rings, which should be accompanied by increased oil consumption.
9. If low compression is detected in any cylinder, a small amount of engine oil is poured into it through the spark plug hole and the pressure is measured. If the compression pressure increases, then the cause is probably wear on the piston rings. If the compression meter readings do not change, then the reason is a leaky valve seat. The reason may also be a leak in the gasket between the head and the cylinder block. In this case, it is necessary to remove the head and check the mating.
There are special liquids on sale that, when introduced into the cylinders, increase compression. However, they should be seen as temporary measures.
After checking, remove the compression gauge, screw in the spark plugs and tighten them to 20 Nm. Connect the plug connections of the spark plugs.
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