Section 6.4 Improper Assembly

Section 6.4
Improper Assembly

Section 6.4.1
Appearance

Bearings can be deformed, bent, crushed, or wear unevenly. Not all examples of improper assemblies look alike. See Figure "Example of Locating Lugs Improperly Nested Shown on Engine" , see Figure "Example of Locating Lugs Improperly Nested Shown off Engine" , and see Figure "Incorrectly Installed Locating Lugs" .‪

Figure 1. Example of Locating Lugs Improperly Nested Shown on Engine

Figure 2. Example of Locating Lugs Improperly Nested Shown off Engine

Figure 3. Incorrectly Installed Locating Lugs

Section 6.4.2
Damage

Types and results of improper assembly are:‪

1. A shifted bearing cap causes the side of the bearing to push against the journal.
2. Bent or twisted connecting rod results in the misalignment of the bore with the journal.
3. Insufficient crush allows for the movement of the bearing within the housing.
4. Excessive crush causes the bearing to bulge inward at the edges. See Figure "Damage from Excessive Crush" .
   

   Figure 4. Damage from Excessive Crush

Section 6.4.3
Possible Causes

Some possible causes for the damage are:‪

1. Bearing caps assembled to tightly or not tight enough.
2. Extreme operating conditions.
3. Improper installation. See Figure "Installation with Bearing Caps in Wrong or Reversed Position" and see Figure "Installation with Oil Hole not Aligned with Oil Passage" .
   

   Figure 5. Installation with Bearing Caps in Wrong or Reversed Position

   

   Figure 6. Installation with Oil Hole not Aligned with Oil Passage

Section 6.4.4
Recommendation

The recommended maintenance procedures after finding improper assembly are:‪

1. Replace bearings.
2. Install new engine components.
3. Ensure the correct torque is applied to the caps.
4. Use correct installation procedures.