Maintenance Inspections
Teledyne Continental Motors, Inc.
TM
7-3.7.2.4. Cylinder Differential Pressure Test
Procedure
1.
Perform the test as soon as possible after the engine is shut down to ensure the piston
rings, cylinder walls, and other engine parts are well lubricated and at operating
clearance.
2.
Remove the most accessible spark plug from each cylinder. Identify the cylinder
number and position of the removed spark plugs. Examine the spark plugs to aid in
diagnosing engine and cylinder conditions. Refer to the spark plug manufacturer’s
technical data.
3.
Turn the crankshaft by hand in the direction of rotation until the piston (in the
cylinder being checked) is coming up on its compression stroke.
4.
Install the cylinder adapter in the spark plug hole and connect the Differential
Pressure Tester to the adapter (Figure 7-5).
CYLINDER
PRESSURE
GAUGE
RESTRICTOR
ORIFICE
REGULATOR
PRESSURE
VALVE
COMPRESSED
AIR SOURCE
CYLINDER
PRESSURE
VALVE
CYLINDER
ADAPTER
CYLINDER
REGULATOR
PRESSURE
GAUGE
CYLINDER
PRESSURE
GAUGE
RESTRICTOR
ORIFICE
REGULATOR
PRESSURE
VALVE
COMPRESSED
AIR SOURCE
CYLINDER
PRESSURE
VALVE
REGULATOR
PRESSURE
GAUGE
CYLINDER
ADAPTER
MASTER ORIFICE
(HAND TIGHT)
Establishing Minimum Acceptable
Cylinder Pressure Leakage Limit With
Master Orifice Tool
Performing Differential Pressure Test
Read Minimum Acceptable Cylinder
Leakage Limit on this Gauge
Read Cylinder Leakage
on this Gauge
Figure 7-5.
Differential Pressure Test Equipment Usage
NOTE: The cylinder pressure valve should be in the CLOSED
position
WARNING
Exercise care in opening the cylinder pressure valve, since
sufficient air pressure will be built up in the cylinder to cause it
to rotate the crankshaft if the piston is not at top dead center.
5.
Slowly open the cylinder pressure valve and pressurize the cylinder to 20 psi.
7-18
IOF-240 Series Engine Maintenance Manual
Change 1
31 August 2007