Compression Test Data - Perkins New 1000 Series Workshop Manual

11
New 1000 Series

Compression test data

Tests have shown that many factors affect
compression pressures. Battery and starter motor
condition, ambient conditions and the type of gauge
used can give a wide variation of results for a given
engine.
It is not possible to give accurate data for
compression pressure, but tests have shown that the
results should be within 2000/3500 kPa (300/500 lbf/
2 2
in ) 21,0/35,0 kgf/cm for diesel engines.
Compression tests should only be used to compare
between the cylinders of an engine. If one or more
2
cylinders vary by more than 350 kPa (50 lbf/in ) 3,5
2
kgf/cm , then those cylinders may be faulty.
Compression tests should not be the only method
used to show the condition of an engine, but they
should be used together with other symptoms and
tests.
How to do a compression test
Caution: Before the compression test, ensure that
the battery is in good condition and that it is fully
charged. Also ensure that the starter motor is in good
condition.
1 Ensure that the valve tip clearances are set
correctly.
2 Remove the atomisers.
3 Fit a suitable gauge into the atomiser hole of the
cylinder to be tested.
Caution: Ensure that the engine cannot start:
4 Disconnect the stop solenoid or put the stop control
in the no-fuel position.
5 Operate the starter motor and note the pressure
indicated on the gauge.
6 Repeat for each cylinder.
Workshop Manual, TPD 1350, issue 3 29