Test of compression


The compression test is used to determine how good the compression of each cylinder is.

Note:

Auxiliary equipment may influence the test results. Before the test it is therefore essential to bring the engine to operating temperature and run it for approx 2 minutes at 1200 rpm. This is necessary so the compressed air system will be fully charged and the fan switches off. The compression test ascertains the compression deviations of the individual cylinders. The engine is then operated by the starter motor without injection enabled. During a short time the engine speed reaches its minimum at the top dead centre of each cylinder. This is the point of maximum compression.

Please make sure that the following conditions are fulfilled.

Test prerequisites:

Procedure:

  1. When the compression test has started.

  2. Turn the ignition key to crank the engine.

  3. Do not run the starter motor for more than 7 seconds.