3406E & 3056 INDUSTRIAL ENGINE – Connecting Rod Bearings

Remove & Install Connecting Rod Bearings

Start By:

a. remove oil pump

1. Check the connecting rods and caps for their identification and location.

2. Turn the crankshaft until the connecting rod caps are in the position shown.

3. Remove two bolts (1) and the cap from the connecting rod. Remove the lower half of the bearing from the cap.

4. Push the connecting rod away from the crankshaft. Remove the upper half of the bearing from the connecting rod.

NOTE: Install the bearings dry when the clearance checks are made. Put clean engine oil on the bearings for final assembly.

5. Install the upper half of the bearing in the connecting rod.

6. Pull the connecting rod slowly on to the crankshaft.

7. Install the lower half of the bearing in the cap.

NOTE: Be sure the tabs in the back of bearings are in tab grooves of the connecting rod and cap.

The serviceman must be very careful to use Plastigage, Tool (A) correctly. The following points must be remembered:

* Make sure that the backs of the bearings and the bores are clean and dry.
* Make sure that the bearing locking tabs are properly seated in their slots.
* The crankshaft must be free of oil where the Plastigage touches it.
* Put a piece of Plastigage (A) on the crown of the bearing half that is in the cap. Do not allow the Plastigage to extend over the edge of the bearing.
* Install the bearing cap using the correct torque-turn specifications. Do not use an impact wrench. Be careful not to dislodge the bearing when the cap is installed.
* Do not turn the crankshaft with the Plastigage installed.
* Carefully remove the cap but do not remove the Plastigage. Measure the width of the Plastigage while it is in the bearing cap or on the crankshaft journal. Do this by using the correct scale on the package. Record the measurements.
* Remove the Plastigage before reinstalling the cap.

When using Plastigage, the readings can sometimes be unclear. For example, all parts of the Plastigage are not the same width. Measure the major widths to make sure that they are within the specification range. Also, experience has shown that when checking clearances tighter than 0.10 mm (.004 in) the readings may be low by 0.013 to 0.025 mm (.0005 to .0010 in). Out-of-round journals can give faulty readings. Also, journal taper may be indicated when one end of the Plastigage is wider that the other.

For complete details concerning measuring bearing clearances, see Engine Bearings & Crankshafts, SEBD0531.

8. Use Plastigage (A) to check the bearing clearance.

9. Put Plastigage (A) on the bearing.

10. Put 4C-5593 Anti-Seize Compound on the threads and seat surfaces of the rod bolts.

NOTE: Be sure the cylinder numbers on the rod cap and rod are the same and are on the same side of connecting rod. Numbers are on the same side of the rod and cap as are the bearing tab slots. If new rods are installed, put the cylinder number on the rod and cap.

NOTE: Do not turn the crankshaft when Plastigage (A) is in position.

11. Install rod caps (2). Install the two bolts. Tighten each bolt to a torque of 90 ± 8 N·m (67 ± 6 lb ft). Put a mark on the bolts and cap, and tighten the bolts an additional 90 ± 5 degrees from the mark. Remove the rod cap. Remove Plastigage (A), and check the bearing clearance. The bearing clearance must be 0.071 to 0.168 mm (.0028 to .0066 in) for new bearings. Maximum clearance with used bearings is 0.25 mm (.010 in).

12. Put clean engine oil on lower half of the bearing. Install the rod cap again. Tighten each rod bolt a torque of 90 ± 8 N·m (60 ± 6 lb ft). Put a mark on the nuts and cap, and tighten the nuts an extra 90 ± 5 degrees from the mark.

13. Do Steps 1 through 12 for the remainder of the connecting rod bearings.

End By:

a. install oil pump