Lycoming IO-390-D Series Maintenance Manual page 204

(15) Tighten the nuts on thru-studs (to maintain bearing pre-load) at the:
(a) Rear of Cylinder 2 (tighten both sides at the same time).
(b) Rear of Cylinder 4 (tighten on the left side).
(c) Front of Cylinder 1 (tighten both sides at the same time).
(16) Torque the nuts in sequence at positions 1st, 2nd, and 3rd to 25 ft.-lb (34 Nm).
(17) Re-torque the nuts in sequence at positions 1st, 2nd, and 3rd to 50 ft.-lb. (68 Nm).
(18) Torque the front bolts at position 4 on the left side to 25 ft.-lb (34 Nm).
(19) Torque the1/4-in. nuts at positions 5 thru 10 (in the order shown in Figure 88) to 96 in.-
lb. (11 Nm).
(20) Torque the remaining crankcase fasteners as indicated in Table 5.
(21) Make sure all fasteners on the crankcase are torqued correctly and none are loose.
(22) Install the 3/8 in. slotted nut and washer on the stud at the rear camshaft bearing (Figure
89). Torque the nut to 215 in.-lb. (24 Nm). Safety wire the nut as shown in Figure 89.
(23) Apply Loctite
behind the governor pad.
(24) Install the bolts behind the governor pad. Torque the bolts per the torque values listed in
Table 5.
Figure 89
Nut on Stud at Rear Camshaft Bearing
CAUTION
Fastener
1/2-in. Nuts, thru-studs
7/16-in. Nuts
3/8-in. Nuts
NOTICE: Any additional crankcase fastenings not specifically called out in this procedure
can be tightened in any sequence using the torque values shown above.
72-20
Page 178
®
564 or equivalent to the threads of the bolts (Figure 90) to be installed
MAKE SURE ALL FASTENERS ON THE CRANKCASE ARE
TORQUED CORRECTLY AND NONE ARE LOOSE.
Table 5
Crankcase Fastener Torque Values
Torque
50 ft.-lb. (68 Nm)
35 ft.-lb. (48 Nm)
25 ft.-lb. (34 Nm)
IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
Figure 90
Bolts Behind Governor Pad
Fastener
5/16 in. Bolts
1/4 in. Nuts
1/4 in. Shear Nuts
© 2020 Avco Corporation. All Rights Reserved
Torque
17 ft.-lb. (23 Nm)
96 in.-lb. (11 Nm)
55 in.-lb. (6 Nm)
March 2020