2014 Jeep Wrangler JK Factory Service Manual 09 - Engine, 2.8L Diesel

ROD, Piston and Connecting

DESCRIPTION

The pistons (2) are of a free floating design. Oil jets in the engine block lubricate and cool the piston and piston pin (3) assembly. The connecting rods (1) have a pressed in place wrist pin bushing which is lubricated by the oil jets. Connecting rod (7) and bearing caps have cracked mating surfaces and are not interchangeable.

REMOVAL



NOTE:

Both the connecting rod and the connecting rod cap are paint marked to aid during assembly. Paint marks disappear after time. If the rod and the cap are not marked with paint, paint mark or scribe them before disassembly.

  1. Disconnect negative battery cable.

    2.  
  2. Remove cylinder head (Refer to 09 - Engine/Cylinder Head - Removal) .

    3.  
  3. Raise and support the vehicle (Refer to 04 - Vehicle Quick Reference/Hoisting - Standard Procedure) .

    4.  
  4. Remove the oil jets (Refer to 09 - Engine/Lubrication/JET, Piston Oil Cooler - Removal) .

    5.  
  5. Remove top ridge of cylinder bores with a ridge reamer before removing pistons from cylinder block. Be sure to keep top of pistons covered during this operation.

    6.  
  6. Piston and connecting rods must be removed from top of cylinder block. Rotate crankshaft so that each connecting rod is centered in cylinder bore.

    NOTE:

    Be careful not to nick or scratch crankshaft journals


    7.  
  7. After removal, install bearing cap on the mating rod and mark pistons with matching cylinder number when removed from engine block.

    8.  

PISTON PIN - REMOVAL

  1. Secure connecting rod (1) in a soft jawed vice.

    2.  
  2. Remove the snap rings securing piston pin (3).

    3.  
  3. Push piston pin (3) out of piston (2) and connecting rod (1).

    4.  

PISTON RING - REMOVAL

  1. Reference the ID mark on top of first and second piston rings must be facing up.

    2.  
  2. Using a suitable ring expander, remove top and second piston rings.

    3.  
  3. Remove upper oil ring side rail, lower oil ring side rail and then the oil expander from piston.

    4.  
  4. Carefully clean carbon from piston crowns, skirts and ring grooves ensuring the 4 oil holes in the oil control ring groove are clear.

    5.  

INSPECTION


PISTONS

  1. Piston Diameter: Size: 91.912 - 91.928 mm (3.6185 - 3.6192 in.) Maximum wear limit .05 mm (.0019 in.).

    2.  
  2. Check piston pin bores in piston for roundness. Make 3 checks at 120° intervals. Maximum out of roundness .05 mm (.0019 in.).

    3.  
  3. The piston diameter should be measured approximately 15 mm (.590 in.) up from the base.

    4.  
  4. Skirt wear should not exceed 0.1 mm (.00039 in.).

    5.  
  5. The clearance between the cylinder liner and piston should not exceed 0.065-0.083 mm (.0025-.0032 in.).

    6.  

CONNECTING RODS

CAUTION:

Connecting rod bolts must be replaced when disassembled. When assembling the connecting rod (2), be sure that the connecting rod pawl (1) on each of the connecting rod caps is facing the rear (fly wheel) side of the engine.



NOTE:

Do Not lubricate the new connecting rod bolts. They are already coated with a anti scuff treatment.

  1. Assemble connecting rod bearings (4) and bearing caps to their respective connecting rods (2) ensuring that the serrations on the cap and reference marks are aligned.

    2.  
  2. Tighten connecting cap bolts to 10 N·m (89 in. lbs.).

    3.  
  3. Without loosening connecting rod bolts, tighten all bolts to 30 N·m (22 ft. lbs.).

    4.  
  4. Using a torque angle gauge, tighten each bolt an additional 40°.

    5.  
  5. Recheck all bolt tightening with a torque wrench set to 88 N·m (65 ft. lbs.).

    6.  
  6. Check and record internal diameter of crank end of connecting rod (2).

    7.  

CAUTION:

When changing connecting rods (2), DO NOT use a stamp to mark the cylinder location. Identify the connecting rods (2) and caps location using a paint marker. All four must have the same weight. Replacement connecting rods (2) will only be supplied in sets of four.

Connecting rods (2) are supplied in sets of four since they all must be of the same weight category. The weight of the connecting rod is identified by a paint mark (1) on the connecting rod.


PISTON PINS

  1. Measure the diameter of piston pin in the center and both ends. For specification, (Refer to 09 - Engine - Specifications) .

    2.  

INSTALLATION

  1. Before installing pistons, and connecting rod assemblies into the bore, be sure that compression ring gaps are staggered so that neither is in line with oil ring rail gap.

    2.  
  2. Before installing the ring compressor, make sure the oil ring expander ends are butted together.

    3.  
  3. Immerse the piston head and rings in clean engine oil, slide the piston ring compressor, over the piston and tighten. Ensure position of rings does not change during this operation.

    4.  
  4. Face arrow on piston towards front of engine.

    5.  
  5. Each connecting rod has its own letter class (1) to a specific connecting rod journal diameter.

    6.  
  6. To determine the correct bearing size for each cylinder. Each connecting rod letter class must be matched with the crankshaft letter class (2) with the bearing selection chart to determine the correct bearing color for each cylinder. The letters stamped into the crankshaft (2) are in the same order as the cylinders. The first letter corresponds to the first cylinder, the second to the second, etc. See bearing selection chart, (Refer to 09 - Engine/Engine Block - Standard Procedure) .

    CAUTION:

    Care must be taken not to nick the crankshaft journal or cylinder bore when installing the pistons.


    7.  
  7. Rotate crankshaft so that the connecting rod journal is on the center of the cylinder bore. Insert rod and piston into cylinder bore and guide rod over the crankshaft journal.

    8.  
  8. Guide the piston down in cylinder bore, using a hammer handle. At the same time, guide connecting rod into position on connecting rod journal.

    NOTE:

    The connecting rod bolts must be replaced every time they are loosened or removed.


    9.  
  9. Using new bolts, install connecting rod caps. Tighten bolts to 10 N·m (88 in. lbs.).

    • Next tighten bolts to 30 N·m (22 ft. lbs.) plus an additional 40 degrees.
    • Next tighten bolts to 88 N·m (65 ft. lbs.).

    10.  
  10. Install the oil jets, (Refer to 09 - Engine/Lubrication/JET, Piston Oil Cooler - Installation) .

    11.  
  11. Install cylinder head, (Refer to 09 - Engine/Cylinder Head - Installation) .

    12.  
  12. Connect negative battery cable.

    13.  

PISTON PIN INSTALLATION

  1. Secure connecting rod (1) in soft jawed vice.

    2.  
  2. Lubricate piston pin (3) and piston (2) with clean engine oil.

    3.  
  3. Position piston (2) on connecting rod (1).

    CAUTION:

    Ensure arrow on piston crown and the bearing cap numbers on the connecting rod are on the opposite side.


    4.  
  4. Install piston pin.

    5.  
  5. Install snap ring in piston (2) to retain piston pin (3) and visually inspect that the snap ring is seated correctly in piston seat.

    6.  
  6. Remove connecting rod (1) from vice.

    7.  

PISTON RINGS - INSTALLATION

  1. Install rings on the pistons using a suitable ring expander.

    2.  
  2. Top compression ring is tapered and chromium plated. The second ring is of the scraper type and must be installed with scraping edge facing bottom of the piston. The third is an oil control ring. Ring gaps must be positioned, before inserting piston into the liners, as follows .

    3.  
  3. Top ring gap must be positioned at the No. 3 position (looking at the piston crown from above).

    4.  
  4. Second piston ring gap should be positioned at the No. 1 position.

    5.  
  5. Oil control ring gap should be positioned at the No. 2 position.

    6.  
  6. When assembling pistons check that components are installed in the same position as before disassembly, determined by the numbers stamped on the crown of individual pistons. Engine cylinders are numbered starting from gear train end of the engine. Face arrow on top of piston toward front of engine. Therefore, the numbers stamped on connecting rod big end should face toward the injection pump side of engine. To insert piston into cylinder use a ring compressor.

    7.