Connecting Rod Installation - Lycoming IO-390-D Series Maintenance Manual

IO-390-D Series Engine Maintenance Manual
IO-390-D Series Engine Maintenance Manual
E. Connecting Rod Installation
NOTICE: Each connecting rod is identified by a letter (A, E, S, etc.) as a designation for
weight class. All of the connecting rods installed on the crankshaft must be of the
same weight class.
(1) Ensure that all of the connecting rods have the same weight class letter.
(2) Apply specified lubricant to the connecting rod bearings (per the latest revision of Service
Instruction No. SI-1059) in Figure 50. Different lubricants are used on the connecting rod
bearings.
NOTICE: Anytime either the connecting rod bolt and/or nut pairs are removed from a
Lycoming engine, replace both the bolt and nut pairs with new "Service Use
Only" hardware regardless of apparent condition.
(3) Refer to the latest revision of Service Instruction No. SI-1458 to identify the correct P/Ns
for the new connecting rods bolts.
(4) Make sure the new connecting rod bolt and new nut pairs are clean, free of dirt and debris
and that the threads are not damaged.
(5) Install the new lubricated matched set bearing insert pair on each connecting rod, one
bearing insert on the connecting rod and the other bearing insert on the connecting rod
cap. Ensure that the tang of each bearing insert fits and seats within the slot of either the
connecting rod as well as the connecting rod cap.
NOTICE: Do not install standardized connecting rod bolts in connecting rods with oversize
bolt holes. Refer to the latest revision of Service Instruction No. SI-1458 for
details.
(6) Apply Loctite
threads of the new connecting rod bolts (Figure 50). Wipe away excess lubricant with a
clean, lint-free cloth.
(7) Apply engine oil mixture to the crankpin journals.
(8) Install each connecting rod pair (with the bearing inserts installed) on their respective
crank pins on the crankshaft (where the numbers on the connecting rods and bearing
locks point down - toward the oil sump.)
© 2020 Avco Corporation. All Rights Reserved
March 2020
Connecting Rod Assembly Lubrication
®
Food-Grade Anti-Seize Lubricant or equivalent to the bottom two or three
Figure 50
72-20
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