Maintenance Inspections
Teledyne Continental Motors, Inc.
TM
7-20
IOF-550 Permold Series Engine Maintenance Manual
1 April 2007
Table 7-3.
Differential Pressure Test Results
Air Discharge
Source
Differential Pressure
Test Result
Symptoms/Observations Recommended
Action
Little to no air
discharge at oil
filler/crankcase
breather.
Cylinder Differential
Pressure Test reading
abnormally high
Oil consumption abnormal
|
with oil discharge out engine
breather.
Borescope inspection reveals
heavy carbon deposits in
combustion chamber and on
piston crown.
Excessive oil puddling in
cylinder barrel.
Remove cylinder for repair.
Above leakage limit.
Normal cylinder borescope
inspection results.
Continue engine in service.
Air discharge into
induction system
Below leakage limit.
Normal cylinder borescope
inspection results.
Fly aircraft at cruise power
{
and repeat Cylinder
Differential Pressure Test.
Below leakage limit after
re-check.
Not applicable
Remove cylinder for repair.
Above leakage limit.
Normal cylinder borescope
inspection results.
Continue engine in service.
Air discharge into
exhaust system
Below leakage limit.
Normal cylinder borescope
inspection results.
Fly aircraft at cruise power
{
and repeat Cylinder
Differential Pressure Test.
Below leakage limit after
re-check.
Not applicable
Remove cylinder for repair.
Air escaping at spark
plug spot face
Not Applicable
Dye check of area reveals
cracks.
Remove cylinder for
replacement.
Air discharge at
cylinder head to barrel
juncture or between
barrel fins
Above leakage limit
First cylinder head fin above
cylinder barrel wet with oil or
baked on oil residue. See
also latest revision of TCM’s
Service Bulletin SB96-12 for
additional test to be
performed.
Remove cylinder for
replacement.
{
Fly the aircraft at a cruise power setting between 65 and 75 percent power, as specified in the aircraft Aircraft
Flight Manual/Pilots Operating Handbook (AFM/POH), for a duration that will allow the engine oil and cylinder
head temperatures to stabilize, or at least 45 minutes. Perform an additional differential compression test on the
suspect cylinder(s).
|
A sudden increase in oil consumption from the established or normal trend for the engine or an oil
consumption rate that exceeds 1/2 quart (liter) per hour during normal engine operation.