C3.3 Industrial Engine Caterpillar

The cylinder compression test should only be used in order to compare the cylinders of an engine. The pressure in the cylinder should be between 300 to 500 kPa (43.5120 to 72.5200 psi). If one or more cylinders vary by more than 350 kPa (51 psi), the cylinder and related components may need to be repaired.

A compression test should not be the only method which is used to determine the condition of an engine. Other tests should also be conducted in order to determine if the adjustment or the replacement of components is required.

Before the performance of the compression test, make sure that the following conditions exist:

• The battery is in good condition.

• The battery is fully charged.

• The starting motor operates correctly.

• The valve lash is set correctly.

• All fuel injectors are removed.

• The fuel supply is disconnected.

1. Install a gauge for measuring the cylinder compression in the hole for a fuel injector.

2. Operate the starting motor in order to turn the engine. Record the maximum pressure which is indicated on the compression gauge.

3. Repeat Steps 1 and 2 for all cylinders.