Cylinder compression control (Mazda Capella GD)

If it is determined that a cylinder no longer has the compression or compression pressure it had when it left the factory, a compression pressure tester can be purchased and the pressure in individual cylinders can be checked. Leaky valves, pistons or piston rings are detected with its help. If the engine is still in fairly new condition, the following compression pressures should be obtained:

Engine F6 - 11.5 kgf/cm²

— wear limit — 8.1 kgf/cm²

FE engine - F8 13.0 kgf/cm²

— wear limit — 9.1 kgf/cm²

FE engine 12 valves - 14.5 kgf/cm²

— wear limit 10.2 kgf/cm²

DOHC engine, fuel containing lead - 14.5 kgf/cm²

— wear limit 10.2 kgf/cm²

DOHC engine, lead-free fuel - 14.0 kgf/cm²

— wear limit — 9.8 kgf/cm²

DOHC engine - 30.0 kgf/cm²

— wear limit — 27.0 kgf/cm²

If the compression is below these values, you need to decide whether to install a new engine or rebuild the existing one. It is important to know whether one cylinder has "bad" compression or all. If, for example, a difference of 1.0 a is assumed inside an individual cylinder, then this may mean that the valves of the "bad" cylinder are stuck, and you only need to repair the cylinder head, i.e. the valves. It is possible that the piston rings are hanging, so that compression along the piston may have leaked into the crankcase. A uniform loss of compression can indicate worn cylinder bores in most cases.

[Data provided by the website: MAZbook.ru]

To check the compression, you need to bring the engine to operating temperature and remove the spark plugs. Stop the engine for approximately 10 minutes to allow the exhaust pipe to cool. For a gasoline engine, remove the spark plugs and connect a small wire from the ignition coil. For a diesel engine, remove the fuel line, injectors, copper discs and shaft pulleys and take out the fuel shut-off valve plug. Close the return fuel line connection on the high pressure pump (insert a plug). Install the compression tester according to the manufacturer's instructions. Another person should now get into the car and turn on the starter within 5 seconds while the accelerator pedal is fully depressed to the floor. Check all cylinders in turn and compare with nominal dimensions. If the compression in the cylinder is too low, you can, as an emergency measure, fill the cylinder through the hole in the spark plug with one of the preparations that can be purchased at auto repair shops for temporary cylinder sealing. Demand this drug in your auto stores.