ELEMENT 0005283 - Caterpillar

Table 1
Tools Needed    
Part Number     Part Name     Qty    
9U-6274     Compression Test Tool Gp     1    The following conditions can affect the results of the cylinder compression test:
Battery
Condition of the starter motor
Ambient conditions
Quality of the compression gauge
Illustration 1 g00564993
Checking compression of engine
Remove the fuel injection nozzle from the cylinder in order to measure the compression for that cylinder.
Connect a compression gauge to the cylinder.
Disconnect the fuel shutoff solenoid or hold the governor stop lever in the engine stop position.
Operate the starter motor and record the pressure on the compression gauge.
Repeat for each cylinder.Note: Compression tests should only be used to compare pressures between cylinders of an engine. If one or more cylinders vary more than 350 kPa (51 psi) then those cylinders may be damaged.Note: The cylinder compression test should not be the only test for determining the condition of an engine.
Table 2
    Standard at Assembly     Repair Limit    
Compression Pressure (1)    
2940 kPa (427 psi)    
2650 kPa (384 psi)    
( 1 ) The compression pressure is taken at 300 rpm.
Repair procedures must be taken if the compression is lower than the repair limit.
Be sure to measure the compression on all of the cylinders. If all of the cylinders are not checked an improper diagnosis may result. The compression pressure will vary with the change in engine rpm. It is necessary to keep the engine rpm constant for all cylinders when you are taking a compression reading.