IO-390-D Series Engine Maintenance Manual
72-20
© 2020 Avco Corporation. All Rights Reserved
Page 178
March 2020
IO-390-D Series Engine Maintenance Manual
(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
®
564 or equivalent to the threads of the bolts (Figure 90) to be installed
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
Figure 90
Bolts Behind Governor Pad
CAUTION
MAKE SURE ALL FASTENERS ON THE CRANKCASE ARE
TORQUED CORRECTLY AND NONE ARE LOOSE.
Table 5
Crankcase Fastener Torque Values
Fastener
Torque
Fastener
Torque
1/2-in. Nuts, thru-studs
50 ft.-lb. (68 Nm)
5/16 in. Bolts
17 ft.-lb. (23 Nm)
7/16-in. Nuts
35 ft.-lb. (48 Nm)
1/4 in. Nuts
96 in.-lb. (11 Nm)
3/8-in. Nuts
25 ft.-lb. (34 Nm)
1/4 in. Shear Nuts
55 in.-lb. (6 Nm)
NOTICE:
Any additional crankcase fastenings not specifically called out in this procedure
can be tightened in any sequence using the torque values shown above.
