Lycoming YO-233-B2A Maintenance Manual page 156

F. Install the cylinder base hold-down nuts (Figures 16 and 40) on the thru-studs and cylinder
hold-down studs.
CAUTION TORQUE THE CYLINDER NUTS IN A SPECIFIC SEQUENCE.
G. Torque the cylinder base hold-down nuts as follows:
(1) Torque the 1/2 in. nuts to 25 ft.-lb (34 Nm) in the sequence shown in Figure 40.
(2) Torque the 1/2 in. nuts to 50 ft.-lb (68 Nm) in the sequence shown in Figure 40.
(3) Torque all 3/8 in. nuts to 25 ft.-lb (34 Nm) in the sequence shown in Figure 40. The
torque sequence for these nuts is optional.
Sequence of Tightening Cylinder Base Hold-Down Nuts
(4) Use the same sequence shown in Figure 40, complete a torque check to 50 ft.-lb. (68 Nm)
for all 1/2-in. nuts on the cylinder base studs.
(5) Tighten both ends of the free thru-studs at the same time at the all locations. Make sure
all thru-studs have at least 1-1/2 threads above attaching nuts at both ends.
(6) Make sure all cylinder base hold-down nuts are torqued. Complete a torque check of all
nuts on the cylinder base using the torque wrench to apply the appropriate torque on each
nut for 5 seconds. If the nut does not turn, it is correctly torqued.
(7) Apply torque seal to all cylinder base hold-down nuts where the nut contacts the barrel.
CAUTION MAKE SURE ALL CYLINDER FASTENERS ON THE CRANKCASE
72-30
Page 136
Figure 40
ARE TORQUED CORRECTLY AND NONE ARE LOOSE.
YO-233-B2A Engine Maintenance Manual
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February 2021