Cummins ISX11.9 CM2250 – Service Manual 001-054   Piston and Connecting Rod Assembly

The connecting rod for the ISX11.9 CM2250 uses a fractured split connection between the rod cap and the rod. Connecting rods with a fracture split surface must be treated with caution. The two pieces of the connecting rod can not be rubbed together. This will damage the mating surfaces. Use care to not drop either piece of the connecting rod. Fracture split connecting rods must only be handled if the two pieces of the connecting rod are tightened to the correct specification, or completely separated.

WARNING  To reduce the possibility of personal injury, avoid direct contact of hot oil with your skin.

WARNING  Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

WARNING  Do not remove the pressure cap from a hot engine. Wait until the coolant temperature is below 50°C [120°F] before removing the pressure cap. Heated coolant spray or steam can cause personal injury.

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

WARNING  This component weighs 23 kg [50 lb] or more. To reduce the possibility of personal injury, use a hoist or get assistance to lift this component.

WARNING  Do not rotate the crankshaft with loose or missing connecting rod caps. Damage to the piston cooling nozzles may occur.

• Drain the lubricating oil. Refer to Procedure 007-037 in Section 7.
• Drain the cooling system. Refer to Procedure 008-018 in Section 8.
• Remove the lubricating oil pan. Refer to Procedure 007-025 in Section 7.
• Remove the lubricating oil suction tube. Refer to Procedure 007-035 in Section 7.
• Remove the block stiffener plate. Refer to Procedure 001-089 in Section 1.
• Remove the piston cooling nozzles. Refer to Procedure 001-046 in Section 1.
• Remove the cylinder head. Refer to Procedure 002-004 in Section 2.

WARNING  When using solvents, acids, or alkaline materials for cleaning, following the manufacturer’s recommendations for use. Wear goggles and protective clothing to reduce the possibility of personal injury.

WARNING  Some solvents are flammable and toxic. Read the manufacturer’s instructions before using.

CAUTION  Do not use emery cloth or sandpaper to remove carbon from the cylinder liners. Aluminum oxide or silicon particles from emery cloth or sandpaper can cause serious engine damage. Do not use any abrasives in the ring travel area. The cylinder liner can be damaged.

Use a fine, fibrous, abrasive pad such as Scotch-Brite™ 7448, Part Number 3823258 or equivalent, and solvent to remove carbon from the cylinder liners as needed.

Rotate the crankshaft so that two of the connecting rods are at bottom dead center. Refer to Procedure 009-035 in Section 9.

CAUTION  Do not damage the fractured split surface on the connecting rod or connecting rod cap while the connecting rod caps are removed. If the fractured split surface is damaged, the connecting rod and connecting rod cap must be replaced to reduce the possibility of engine damage. Incorrect assembly can damage the rod.

Do not remove the capscrews at this time.

Loosen the connecting rod capscrews.

Hit the connecting rod capscrews with a rubber hammer to loosen the rod caps.

Remove the capscrews and the rod cap. Note the corresponding rod and rod cap as well as the orientation of the rod cap.

Be careful not to damage the fractured split connection.

DO NOT set the rod cap down on the fractured split face.

NOTE: Both the rod cap and the connecting rod are serialized on one face to make sure of proper orientation.

NOTE: Minimize the number of joint interactions between the connecting rod and rod cap. There is only a finite number of times a connecting rod and rod cap can be assembled and removed before the joint loses its proper interaction.

Remove the bearing shell from the rod cap and mark the cylinder number and the letter “L” on the flat surface of the bearing tangs.

Install two of the capscrews back into the rod finger tight.

Use a T-handle piston pusher. Push only against the head of the capscrew, to push the rod up far enough to allow the upper bearing shell to be removed.

DO NOT push against the fractured split face of the rod.

Use caution not to scratch or damage the journal with the rod, capscrew, or piston pusher.

Remove the bearing shell and mark the cylinder number and the letter “U” on the flat surface of the bearing tangs.

Use both hands to remove the piston and connecting rod assembly.

The piston and connecting rod assemblies must be installed in the same cylinder from which they were removed to provide for proper fit of worn mating surfaces if parts are reused.

Use a tag to mark the cylinder number from which each piston and connecting rod assembly was removed.

Pistons that are reused must be installed in the same orientation as when removed from the engine. Mark the front side of the piston and piston pin with layout ink, or equivalent, after removal.

Place the connecting rod and piston assemblies in a container to protect them from damage.

The two pieces of the connecting rod can not be rubbed together. This will damage the mating surfaces. Use care to not drop either piece of the connecting rod. Fracture split connecting rods must only be handled if the two pieces of the connecting rod are torqued to the correct specification, or completely separated.

Use internal snap ring pliers to remove the snap rings from both sides of the piston.

NOTE: If the piston is being replaced, the piston pin must also be replaced.

CAUTION  Do not use a hammer to remove the piston pins. The piston can distort, causing it to seize in the liner.

If the piston pin can not be easily removed by hand, place the piston and connecting rod assembly in a container of water. Heat the piston in boiling water for 15 minutes.

Use a blunt tool to push the piston pin from the piston and connecting rod assembly.

The piston and connecting rod assemblies must be installed in the same cylinder from which they were removed to provide for proper fit of worn mating surfaces if parts are reused.

Use a tag to mark the cylinder number from which each piston and connecting rod assembly was removed.

Use the following procedure to clean and inspect the pistons and piston pins. Refer to Procedure 001-043 in Section 1.

Use the following procedure to clean and inspect the connecting rods. Refer to Procedure 001-014 in Section 1.

CAUTION  The retainer snap ring must be seated completely in the piston pin groove to prevent engine damage during engine operation.

Install a new snap ring into one piston pin bore of each piston.

Install the snap ring with the gap at the top or bottom of the piston pin bores.

If the pistons are being reused, the piston and pin must be matched to the way they were when they were removed.

CAUTION  Generously coat both piston pin bores with a heavy weight gear oil, such as 85W-140 EP, when assembling the pistons. Also lubricate the connecting rod bushing. If gear oil is not available, Lubriplate™, Part Number 3163086, is permissible. Failure to adequately lubricate the pin joint can result in extensive engine damage.

Use clean 85W-140 oil to coat the piston pin.

CAUTION  The piston must be installed onto the connecting rod with the correct orientation or engine damage can occur.

For pistons that are being reused, the piston, piston pin, and connecting rod must be installed in the same orientation as when were removed from the engine.

New pistons are symmetrical and do not require a specific orientation during installation.

NOTE: Pistons do not require heating to install the pin, however, the pistons do need to be at room temperature or above.

Install the pin through the piston and connecting rod.

CAUTION  The snap ring must be seated completely in the piston groove to prevent engine damage during engine operation.

Install a new snap ring into the piston pin bore.

Install the snap ring with the the gap at the top or bottom of the piston pin bore.

Install the piston rings. Refer to Procedure 001-047 in Section 1.

Rotate the crankshaft so the connecting rod journal of the connecting rod being installed is at bottom dead center. Refer to Procedure 009-035 in Section 9.

Immerse the piston in a container of clean 15W-40 oil.

Remove the piston from the container. Let the excess oil drain from the piston.

Use a clean, lint-free cloth to clean the connecting rods and bearing shells.

Do not lubricate the backside of the bearing shells. The operating clearance of the bearing will be reduced and the bearing can be damaged during engine operation.

If new bearings are not used, the used bearings must be installed on the same connecting rod from which they were removed.

Install the upper bearing shell into the connecting rod.

The tang of the bearing shell (2) must be in the slot of the cap (1). The end of the bearing shell must be even with the cap mounting surface.

Use Lubriplate™ 105, Part Number 3163086 or equivalent, to coat the entire inside circumference of the bearing shell.

Apply a film of clean 15W-40 oil to the cylinder liner.

Inspect the cylinder liners for reuse. Refer to Procedure 001-028 in Section 1.

Apply a film of clean 15W-40 oil to the cylinder liner.

Use piston ring compressor, Part Number 4919273, to compress the rings.The cylinder block and all parts must be clean before assembly.

Install two guide pins, Part Number 3163097, in the connecting rod.

For pistons that are being reused, the piston, piston pin, and connecting rod must be installed in the same orientation from which they were removed from the engine.

The long side of the connecting rod will be on the left side of the engine and the short side of the connecting rod will be on the right side of the engine when properly installed.

CAUTION  Do not use a metal drift to push the piston into the cylinder liner. The piston rings or cylinder liner can be damaged.

Hold the ring compressor against the cylinder liner. Push the piston through the ring compressor and into the cylinder liner. Push the piston until the top ring is completely in the cylinder liner.

If the piston does not move freely, remove the piston and inspect for broken or damaged rings.

Align the connecting rod with the crankshaft while pushing the piston and connecting rod assembly into place.

Install the bearing shell into the connecting rod cap with the tang (2) of the bearing in the slot (1) of the cap.

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

CAUTION  Do not damage the fractured split surface on the connecting rod or connecting rod cap while the connecting rod caps are removed. If the fractured split surface is damaged, the connecting rod and connecting rod cap must be replaced to reduce the possibility of engine damage. Incorrect assembly can damage the rod.

NOTE: Make sure that the rod cap is installed only on the connecting rod from which it was removed, and that the rod cap is properly oriented when installing.

NOTE: Both the rod cap and the connecting rod are serialized on one face to make sure of proper orientation.

Install the cap onto the connecting rod.

NOTE: Minimize the number of joint interactions between the connecting rod and rod cap. There is only a finite number of times a connecting rod and rod cap can be assembled and removed before the joint loses its proper interaction.

Lubricate the threads and underside of the head of the connecting rod capscrews with clean engine oil.

Thread the capscrews into the connecting rod and hand tighten.

Tighten the capscrews in numerical sequence.

Measure the connecting rod side clearance.

Connecting Rod Side Clearance

The connecting rod must move freely from side to side on the crankshaft journal. If the rod does not move freely, remove the rod cap and make sure the bearing shells are the correct size. Check for dirt or damage on the crankshaft and the bearing shells.

Repeat the above steps to install the remaining bearing shells and connecting rod caps.

WARNING  Some state and federal agencies have determined that used engine oil can be carcinogenic and cause reproductive toxicity. Avoid inhalation of vapors, ingestion, and prolonged contact with used engine oil. If not reused, dispose of in accordance with local environmental regulations.

WARNING  Coolant is toxic. Keep away from children and pets. If not reused, dispose of in accordance with local environmental regulations.

• Install the piston cooling nozzles. Refer to Procedure 001-046 in Section 1.
• Install the block stiffener plate. Refer to Procedure 001-089 in Section 1.
• Install the lubricating oil suction tube. Refer to Procedure 007-035 in Section 7.
• Install the lubricating oil pan. Refer to Procedure 007-025 in Section 7.
• Install the cylinder head. Refer to Procedure 002-004 in Section 2.
• Prime and fill the lubricating oil system. Refer to Procedure 007-037 in Section 7.
• Fill the cooling system. Refer to Procedure 008-018 in Section 8.
• Operate the engine to normal operating temperature and check for leaks.