Intake And Exhaust Valve Guide Replacement - Lycoming TEO-540-C1A Maintenance Manual

TEO-540-C1A Engine Maintenance Manual
TEO-540-C1A Engine Maintenance Manual

17. Intake and Exhaust Valve Guide Replacement

Any time a valve guide is to be replaced, send the engine cylinder to an authorized vendor who
can complete this replacement.
18. Intake and Exhaust Valve Seat Replacement
If an intake or exhaust valve seat (Figure
48) is damaged or must be replaced, send
the engine cylinder to an authorized vendor
who can complete this replacement.
19. Barrel Glaze and Varnish Removal from Interior Cylinder Barrel
A. Use a self-centering, self-bottoming hone that follows the choke located in the top of the
cylinder barrel.
B. Use kerosene or light engine oil for lubrication while honing.
C. Put the deglazing hone in a low-speed drill.
D. Surface hone each cylinder barrel with a minimum of six to eight passes over the glazed
surface, using a smooth up and down motion of the hone to achieve a good cross-hatch
pattern on the cylinder barrel wall.
E. Thoroughly clean the hone.
F. Wipe as much of the abrasive build-up from the cylinder walls and recesses as possible,
especially the recesses formed by the top of the cylinder barrel and the bottom of the cylinder
head.
G. Make a hooked tool from soft wire and rub the tool back and forth in the recess to loosen any
built-up abrasive. Complete this task each time the cylinder is flushed. There must not be any
abraded material in this area.
H. Complete the "Cylinder Cleaning" procedure in Chapter 05-30.
I. Lubricate the internal cylinder barrel thoroughly with SAE 50 engine oil or a rust
preventative oil that conforms with MIL-C-6529.
NOTICE: If step wear is found inside the cylinder barrel, measure it using the dial bore gage
(which is usually used to measure cylinder diameter). If the depth of the step wear is
less than 0.0025 in. (0.0635 mm), remove the step as per the previous steps to
remove cylinder barrel glaze. If the barrel contains a wear step exceeding 0.0025 in.
(0.0635 mm), replace the cylinder. Record the condition and corrective action in the
engine logbook.
In some cylinders, a small rough area can be found at either end of the barrel
extending less than 0.250 in. (6.35 mm) from the end. This condition is a result of
the manufacturing process and has no effect on the quality or condition of the barrel.
© 2018 Avco Corporation. All Rights Reserved
November 2018
Figure 48
Intake and Exhaust Valve Seats
72-30
Page 247