Exhaust Valve And Guide Inspection - Lycoming TEO-540-C1A Maintenance Manual

TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual
Borescope Inspection Steps, Results, and Corrective Action
Inspection Step
Examine valve seat inserts for
scoring, pitting, erosion,
burning or damage
Examine spark plug Heli-
®
Coils for protrusion into the
combustion chamber
Look for discoloration on the
circumference of the exhaust
valve face
Look for cracks and erosion
on the exhaust valve face
Look for discoloration on the
circumference of the intake
valve face
Look for cracks and erosion
on the intake valve face
Examine the cylinder bore for
scoring, rubbing, or corrosion
Look for excessive oil in the
cylinder
Examine the piston crown for
erosion or damage

6. Exhaust Valve and Guide Inspection

On TEO-540-C1A engines, this inspection is to be done after every 1000 hours of engine
operation or earlier if valve sticking is suspected.
NOTICE: If valve sticking is a problem, this inspection must be done every 400 hours. Refer
to "Corrective Action for Valve Sticking" in this chapter.
Sticking between the valve stem and guide (on intake and exhaust valves) can
substantially change valve opening and closing. If the valve cannot open or close
correctly, incomplete combustion will occur, which can cause formation of more
deposits and increased valve sticking. Because a correctly-timed sequence of valve
opening and closing is essential to efficient and reliable engine operation, the cause
of valve sticking must be identified and corrected.
© 2018 Avco Corporation. All Rights Reserved
November 2018
Table 3
If these are the results...
Eroded, scored, burnt, pitted
or damaged valve seats
®
Spark plug Heli-Coil
protrudes into combustion
chamber
Discoloration on the
circumference of the exhaust
valve face
Cracks or erosion on the
exhaust valve face
Discoloration on the
circumference of the intake
valve face
Cracks or erosion on the
intake valve face
Scoring or piston rub or
corrosion on cylinder bore
Excessive oil in the cylinder
Erosion or damage on piston
crown
Take this corrective action...
Replace the cylinder or send the
engine cylinder to an authorized
vendor to replace the valve seat.
Replace the Heli-Coil
"Heli-Coil Replacement"
®
procedure in this chapter.
Remove and examine the exhaust
valve.
Remove and examine the exhaust
valve.
Remove and examine the intake
valve.
Replace the intake valve.
Remove and examine the engine
cylinder.
Remove and examine the oil
suction screen and the oil filter
per instructions in Chapter 12-10.
Remove and examine the engine
cylinder.
Remove and examine the oil
suction screen and the oil filter
per instructions in Chapter 12-10.
Remove the engine cylinder and
examine the piston.
®
per the
72-30
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