C3.3B Tier 4 Interim and EU Stage 3A Engines for Caterpillar Built Machines – Compression – Test

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.

• The fuel supply is disconnected.

1. Start the engine. Bring the engine to normal operating temperature.

2. Stop the engine.

3. Disconnect the fuel supply.

4. Remove the air cleaner, the muffler, and all of the glow plugs.

5. Install a compression gauge with the appropriate adapter plug into one of the glow plug holes.

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

   Note: The maximum variation between cylinders is 10 percent or less.

   Table 2

   Allowable Limit for Compression
   C2.6	C3.3
   2206 kPa (320 psi) at 290 rpm	2903 kPa (421 psi) at 250 rpm

   Note: If the measurement is below the allowable limit, examine the cylinder wall and the piston rings.

7. Repeat the entire procedure for the rest of the cylinders.