Cummins ISX11.9 CM2250 – Service Manual 001-006   Bearings, Main

CAUTION  The cylinder block saddle and the cap mating surfaces must be clean and dry when the bearing shells are installed. Used bearings must be installed in their original location or engine damage can occur.

CAUTION  The bearing tang must fit into the slot in the bearing saddle or engine damage can occur.

CAUTION  Do not use a capscrew or any hard metal object to install bearings, as this can damage the crankshaft and cause severe engine damage.

Use clean Lubriplate™ 105 multi-purpose lubricant or equivalent, to lubricate the upper main bearing shell to crankshaft journal mating surface.

Start the bearing into the upper saddle by hand. Slide the bearing into position. Take care to not damage the crankshaft journal while installing the bearing.

If the upper main bearings are installed without the crankshaft in place, check the oil feed hole in the bearing to be sure that at least 80 percent of the oil feed hole in the main bearing saddle is visible.

Use clean Lubriplate™ 105 multi-purpose lubricant or equivalent, to lubricate the inside diameter of the bearing shells and the liner side of the upper thrust bearings.

Align the lower main bearing shell and push it into place.

CAUTION  Make sure the bevel side is toward the crankshaft journal. Incorrect thrust bearing installation will result in engine damage.

NOTE: Only Number 4 main bearing cap has a thrust bearing.

Use clean Lubriplate™ 105 multi-purpose lubricant, or equivalent, to lubricate the liner side of the lower thrust bearings.

Install the lower thrust bearings in the Number 4 main bearing cap with the grooved sides of the thrust bearing facing away from the main bearing cap.

CAUTION  Make sure the grooved side of the thrust bearing is toward the crankshaft journal. Incorrect thrust bearing installation will result in engine damage.

Install the upper thrust bearings in the Number 4 main bearing saddle.

Push the crankshaft toward the rear of the engine to install the front thrust bearing and toward the front of the engine to install the rear thrust bearing.

CAUTION  Only use Loctite™ 518 thread sealant, Part Number 4918675, on the main cap joint mating surface. Other sealants can become hard, brittle, and allow oil and debris into the main bearing/block joint, causing engine damage.

CAUTION  The bead must be 3 to 5 mm [0.12 to 0.20 in] wide and must not enter the main bearing shell inside the main bearing shell inside diameter. Sealant in the main bearing can cause engine damage.

Apply a bead of Loctite™ 518 thread sealant, Part Number 4918675, to the two main bearing cap joint mating surfaces on each main bearing cap, as illustrated.

Use clean 15W-40 engine oil to lubricate the capscrew threads and the underside of the capscrew heads.

Drain the excess oil from the capscrews before installing them and be sure there is not excessive oil in the threaded hole on the block.

CAUTION  The main bearing caps are marked with a “V” Position the “V” mark so that it points to the front of the engine. Incorrect positioning will result in severe engine damage.

Align the capscrew holes in the cap with the holes in the cylinder block. Make sure the lower bearing shell is in position.

Install the capscrews through the cap and into the cylinder block.

To reduce the possibility of bore size issues, clearance issues, or both, the main bearing capscrews must be tightened within 15 minutes of the Loctite™ 518 thread sealant, Part Number 4918675, application.

Make sure the bearing shell does not move.

Seat the main bearing cap evenly by tapping the cap with a non-metallic hammer.

Make sure that the thrust bearings are in place and properly seated when installing the Number 4 main bearing cap.

It is recommended to use an air impact wrench and socket, Part Numbers 3163059 and 3165161, to rotate the capscrews an additional 90 degrees.

Use the torque plus angle method to tighten the main bearing capscrews in the sequence illustrated.

To measure the end clearance of the crankshaft, install a dial indicator onto the oil pan flange.

Place the tip of the gauge against the crankshaft counterweight.

Push the crankshaft toward the rear of the cylinder block.

Set the dial indicator at “0” (zero).

Push the crankshaft toward the front of the cylinder block.

Measure the crankshaft end clearance.

Crankshaft End Clearance – New or Reground

If the end clearance is less than 0.10 mm [0.004 in], loosen all main bearing capscrews one turn.

Push the crankshaft toward the front and then toward the rear of the cylinder block.

Tighten the main bearing capscrews in sequence.

Measure the crankshaft end clearance.

Crankshaft End Clearance – New or Reground

If the crankshaft end clearance is still not within specification, remove the thrust bearings and inspect the thrust bearings. Worn bearings can cause excess end play. Refer to Procedure 001-007 in Section 1. 

Crankshafts that have been reground on the thrust bearing surfaces are marked for oversize thrust bearings on the rear crankshaft counterweight. If the crankshaft counterweight is marked or the crankshaft end clearance is not within specifications, check the thrust bearing part number to make sure the correct thrust ring size is used.

Example: F0.010 = front 0.25 mm [0.010 in]

Example: R0.020 = rear 0.51 mm [0.020 in]

Measure the crankshaft end clearance.

Crankshaft End Clearance – New or Reground

If the crankshaft end play is still less than 0.10 mm [0.004 in], or more than 0.50 mm [0.020 in], the engine must be removed to allow for replacement of the crankshaft. Refer to Procedure 000-001 in Section 0.