B5.9G, B5.9LPG – Troubleshooting and Repair Manual – 001-054   Piston and Connecting Rod Assembly

There are a number of power-related problems, including excessive lubricating oil consumption, smoke, blowby, and poor performance, that can be caused by inadequate sealing between the piston rings and the cylinder walls. A blowby measurement can help detect the problem. Refer to Procedure 014-002.

A free-floating, hollow piston pin is used to attach the piston to the connecting rod. Lubricating the pin and journal is accomplished by residual spray from piston cooling.

The piston pin end of the connecting rod is angle-cut to provide additional bearing surface. The connecting rod end is fitted with a bronze bushing.

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

Drain the lubricating oil. Refer to Procedure 007-025.

Remove the lubricating oil pan and gasket. Refer to Procedure 007-025.

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

Drain the coolant. Refer to Procedure 008-018.

Remove the cylinder head. Refer to Procedure 002-004.

Mark each connecting rod cap according to cylinder.

Engine Barring Tool, Part Number 3824591

Rotate the crankshaft with engine barring tool, Part Number 3824591, until the pistons are below the carbon deposits, which are found above the ring travel area.

CAUTION  Do not use sandpaper or an emery cloth to remove carbon from the cylinder bores. Aluminum oxide or silicon particles from these materials can cause serious engine damage.

Use a scraper or a blunt-edged instrument to loosen the carbon deposits. Do not damage the cylinder with the scraper.

NOTE: When cleaning the cylinder bore, perform a cylindrical motion, not a vertical one, to make sure no leak paths are made.

Remove the remaining carbon with a Scotch-Brite cleaning pad, or equivalent.

Remove the capscrews, connecting rod cap, and connecting rod bearings. Refer to Procedure 001-005.

Push the connecting rod and piston assembly out of cylinder bore. Care
must be taken not to mutilate the connecting rod or bearing.

Use both hands to remove the piston and rod assembly.

NOTE: The piston and connecting rod assemblies must be installed in the same cylinder from which they were removed. This will allow for the proper fit of worn mating surfaces, if the parts are used again.

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

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

Remove the retaining rings.

Refer to Procedure 001-047.

Remove the piston pin.

Refer to Procedure 001-043.

NOTE: Heating the piston is not required.

Piston Ring Expander, Part Number 3823137

Remove the piston rings.

NOTE: Refer to Procedure 001-043 for cleaning and inspection of pistons.

Be sure FRONT marking on piston and the numbers on the connecting rod and cap are oriented as illustrated.

Install the retaining ring in the pin groove on the frontside of the piston.

Lubricate the pin and pin bores with clean gas engine lubricating oil.

Install the pin. Refer to Procedure 001-043.

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

Install the second retaining ring.

Install the bearing shells into both the connecting rod and the connecting rod cap. Make sure the tang on the bearing shells is in the slot of the connecting rod cap and connecting rod.

Lubricate the connecting rod bearings with a light film of clean lubricating engine oil.

Install the piston rings. Refer to Procedure 001-047.

Lubricate the rings and piston skirts with clean gas engine lubricating oil.

Position the rings so that the ring gaps are 120 degrees apart.

Piston Ring Compressor, Part Number 3823290

75 to 125 mm [3 to 5 in]

CAUTION  If using a strap-type ring compressor, make sure the inside end of the strap does not hook on a ring gap and break the ring.

Compress the rings.

Lubricate the cylinder bore with clean gas engine lubricating oil.

Engine Barring Tool, Part Number 3824591

Position the connecting rod journal for the piston to be installed to bottom dead center.

Take care not to damage the cylinder wall when inserting the connecting rod.

Position the piston and connecting rod assembly into cylinder bore with the word FRONT on the piston toward the front of the cylinder block.

Carefully push the piston into the bore while guiding the connecting rod to the crankshaft journal.

Lubricate the threads and underside of the connecting rod capscrew heads with clean lubricating engine oil.

NOTE: The number stamped on the rod and cap at the parting line must match and be installed on the oil cooler side of the engine.

Install the connecting rod cap and capscrews to the connecting rod.

Alternately, tighten the two capscrews.

NOTE: Do not measure the clearance between the rod cap and crankshaft.

Measure the side clearance between the connecting rod and crankshaft using a feeler gauge.

CAUTION  The crankshaft must rotate freely. If the connecting rod is not properly oriented (tang opposite the camshaft), it will contact the camshaft and lock the engine.

Check for freedom of rotation as the connecting rod caps are installed. If the crankshaft does not rotate freely, check the installation of the connecting rod bearings and the bearing size.

Three-Bond™ Sealant, Part Number 3823494

Oil Pan Sealing Surfaces – Sealants

Use Cummins sealant, Part Number 3823494, to fill the joints between the lubricating oil pan rail, gear housing, and rear cover.

Install the lubricating oil pan and gasket. Refer to Procedure 007-025.

Refer to Section 7 for correct oil specifications.

Install the cylinder head. Refer to Procedure 002-004.

Fill the cooling system. Refer to Procedure 008-018.

Fill the engine with clean gas engine lubricating oil. Refer to Procedure
007-025.

Operate the engine to normal operating temperature, and check for leaks.