Piston Removal - Lycoming YO-233-B2A Maintenance Manual

J. Remove push rods and the valve stem cap from the exhaust valve.
K. Remove the nut, lockplate, and shroud tube spring (Figure 15). Discard the lockplate.
L. Remove the shroud tubes through the rocker box.
M. Remove the shroud tube seals from the ends of the shroud tubes. Discard the seals.
N. Remove the washers, seals, hydraulic lifter sockets, and plunger assemblies from the
crankcase. Discard the seals.
O. Remove the cylinder base hold-down nuts (Figure 16).
Figure 16
Cylinder Base Hold-Down Nuts
CAUTION AS EACH CYLINDER IS SEPARATED FROM THE CRANKCASE,
P. Remove the cylinder.
Q. Remove and discard the cylinder base oil seal ring from the cylinder (Figure 17).
CAUTION IF A CYLINDER IS NOT TO BE IMMEDIATELY INSTALLED ON THE
R. After piston removal, examine the connecting rod bushing for damage, wear, or distortion per
the "Connecting Rod Inspection Checklist for YO-233-B2A Engines" in Chapter 72-20.

8. Piston Removal

NOTICE: During removal of each piston pin (Figure 18), the piston will disconnect from the
connecting rod.
A. Support the piston and remove the two piston pin plugs (Figure 18) and piston pin from the
piston.
72-30
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CATCH AND HOLD THE PISTON TO PREVENT IT FROM FALLING
AGAINST THE CRANKCASE AND BEING DAMAGED.
CRANKCASE, INSTALL TORQUE HOLD-DOWN PLATES (ST-222) TO
MAINTAIN THE PRE-LOAD ON THE MAIN BEARINGS.
Piston Assembly
YO-233-B2A Engine Maintenance Manual
TEO-540-A1A Engine Maintenance Manual
Cylinder Base Oil Ring and Cylinder Fins
Figure 18
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Figure 17
February 2021