N14 Base Engine Troubleshooting and Repair Manual – 001-047   Piston Rings

Preparatory Steps

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 WARNING 

To reduce the possibility of personal injury, reduce the possibility of 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.
  • Drain the lubricating oil. Refer to Procedure 007-025.
  • Drain the cooling system. Refer to Procedure 008-018.
  • Remove the lubricating oil pan. Refer to Procedure 007-025.
  • Remove the rocker lever covers. Refer to Procedure 003-011.
  • Remove the compression brakes, if equipped. Refer to Procedure 020-001.
  • Remove the rocker lever assemblies. Refer to Procedure 003-009.
  • Remove the injectors. Refer to Procedure 006-026.
  • Remove the rocker lever housings. Refer to Procedure 003-013.
  • Remove the push tubes. Refer to Procedure 004-014.
  • Remove the cylinder heads. Refer to Procedure 002-004.
  • Remove the piston cooling nozzles. Refer to Procedure 001-046.
 
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Remove

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 WARNING 

When performing the following procedures, wear eye protection. Also, make sure the wire brush is rated for the RPM being used if the brush is motor driven.
 CAUTION 

Do not use abrasive paper to remove the carbon ring. Small particles of abrasive material will cause severe engine damage.
 
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Plug the overhead oil rifle push tube cavities and coolant passages in the block, and use a rotary wire brush to remove the carbon ring from the top of the cylinder liner. Use a scraper that has an aluminum blade if a rotary wire brush is not available.

Use lint-free paper to remove all the broken wire bristles and loose carbon from the cylinders.

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Use the accessory drive pulley to rotate the crankshaft.

Rotate the crankshaft to position two of the connecting rods at bottom dead center.

 
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Measure the connecting rod side clearance.

Connecting Rod Side Clearance
mm in
0.140 MIN 0.005
0.330 MAX 0.013

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If the side clearance does not meet these specifications, do the following:

  • Remove the rod caps. Inspect the rod caps for dirt, damage, and correct bearings.

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  • Install and tighten the rod caps.
  • Measure the side clearance again.

If the side clearance does not meet the specifications, the connecting rod must be replaced.

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NOTE: Do not remove the capscrews.

Loosen the connecting rod capscrews.

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

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Remove the connecting rod capscrews and the rod caps.

Remove the bearing shell from the rod cap, and mark the cylinder number and the letter “L” in the flat surface of the bearing tang.

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Install two connecting rod guide pins, Part Number 3375601.

Use a dead blow mallet to push the rod away from the crankshaft.

Push the rod away from the crankshaft, cover the crankshaft rod journal, and push the rod until the piston rings are outside of the top of the cylinder liner.

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Remove the piston and rod assembly.

The piston crown and skirt and connecting rod assemblies must be installed in the same cylinder number they were removed from to make sure there is a correct fit of worn mating surfaces if parts are used again. Also, the piston skirt and crown must be reinstalled together.

Use a tag to mark the cylinder number from which each piston and rod assembly was removed. Make sure to mark both the skirt and crown on the piston.

The pistons crown must have the cylinder numbers stamped on the piston top toward the camshaft side of the engine. The skirt must also be stamped so it can be matched with the piston crown.

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

 
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 CAUTION 

The rod cap alpha characters must match the alpha characters on the connecting rod and must be installed with the characters aligned to prevent damage to the connecting rods and the crankshaft.
 
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Remove the upper rod bearing.

Mark the cylinder number and the letter “U” in the flat surface of the bearing tang.

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 CAUTION 

To reduce the possibility of damage to the piston rings, do not over expand the piston rings – maximum dimension.

Use the piston ring expander, Part Number 3823871, to remove the piston rings.

Place a tag on the rings, and record the cylinder number of the piston on the tag for future reference (if required).

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

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The piston pin can be easily removed at room temperature by using a blunt tool to manually push the pin from the rod assembly.

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Make sure the piston and rod assembly are correctly marked.

If the pin can not be removed, it is acceptable to put the piston in 66°C [150°F] water for 15 minutes and then manually remove the pin with a blunt tool.

 
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Manually remove the piston skirt from the crown. Extreme caution must be taken to prevent damage to both the crown and skirt.

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Inspect for Reuse

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To check the ring gap, install the new piston rings in the cylinder liner in which they will be used.

Use the top part of the piston to position the ring in the liner correctly.

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Use a feeler gauge to inspect the ring gap. Replace the ring if it does not meet the following specifications:

Piston Ring Gap
mm in
Top Ring 0.43 MIN 0.017
  0.66 MAX 0.027
Second Ring 0.51 MIN 0.020
  0.76 MAX 0.030
Oil Ring 0.25 MIN 0.010
  0.64 MAX 0.025

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Install

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NOTE: The cylinder block must be clean before assembly. Refer to Procedure 001-028 to inspect the cylinder liners for reuse.

Align the piston skirt and crown.

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Install a new snap ring in one of the snap ring grooves of the piston pin bore on each piston.

Heat the pistons in hot tap water, 66°C [150°F], for 15 to 30 minutes.

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Use clean 15W-40 oil to lubricate the connecting rod piston pin bore and the piston pin.

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Remove the piston from the water and lubricate the pin bore with clean 15W-40 oil.

Align the pin bore of the rod with the pin bore of the piston, and install the piston pin. Do not use a hammer to install the piston pin. The piston will be damaged.

The cylinder number of the piston top (1) must be toward the bearing tang (2) side of the rod.

The pin must easily assemble without force; if it does not, inspect it for damage, dirt, poor lubrication, etc.

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Install a new snap ring in the second piston pin bore snap ring groove. The snap ring must be seated completely in the snap ring groove.

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 CAUTION 

To reduce the possibility of damage to the piston rings, do not over expand the piston rings – maximum dimension.

The oil control ring is symmetrical and can be installed in either orientation.

Use piston ring expander, Part Number 3823871, to install the piston rings with the part number, mark, or the word “TOP” toward the top of the piston.

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The ring gap of each ring must not be aligned with the piston pin or with any other ring.

A cross-sectioned view of an oil control ring is shown. The two-piece oil control ring must be installed with the expander ring gap 180 degrees from the gap of the oil ring.

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Install the upper bearing shell in the connecting rod. If used bearing shells are to be installed, each bearing shell must be installed in its original location.

The tang (1) of the bearing shell must be in the slot (2) of the rod.

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Use clean Lubriplate® 105 or its equivalent to lubricate the bearing shell.

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

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Lubricate the piston and the ring assembly by hand with clean 15W-40 oil. Dipping is okay, but draining is very difficult because the piston does not have drain holes. If dipping, only dip up to the pin bore and then hand lubricate it and the remaining skirt.

 
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Install connecting rod guide pins, Part Number 3375601.

Use piston ring compressor, Part Number 3822736, to compress the rings.

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Install the bearing in the connecting rod cap.

The tang (2) of the bearing must be in the slot (1) of the cap.

Lubricate the bearing shell with Lubriplate® 105 or its equivalent. Lubricate the connecting rod capscrew threads and the washer face with 140W oil.

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Use the accessory drive pulley to rotate the crankshaft.

Rotate the crankshaft to position the journal for the connecting rod at bottom dead center.

 
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 CAUTION 

To reduce the possibility of piston damage, do not use a metal object to push the piston into the liner.

The tang of the connecting rod must be toward the camshaft side of the cylinder block.

 
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 CAUTION 

Do not use a hammer or its equivalent to install the piston into the cylinder liner. The piston rings can be damaged.

Install the connecting rod into the cylinder liner, and push the piston down. If the piston does not move freely, remove the piston. Inspect for broken or damaged rings.

When installing the connecting rod, pay close attention to make sure the rod is aligned with the crankshaft rod journal. If the rod is misaligned, it can bind or scrape the crankshaft connecting rod journal side walls.

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Use the guide pins to pull the connecting rod against the crankshaft.

Remove the guide pins.

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Install the bearing in the connecting rod cap.

The tang (2) of the bearing must be in the slot (1) of the cap.

Lubricate the bearing shell with Lubriplate® 105 or its equivalent. Lubricate the connecting rod capscrew threads and the washer face with 140W oil.

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 CAUTION 

The rod cap alpha characters must match the alpha characters on the connecting rod and must be installed with the characters aligned to prevent damage to the connecting rods and crankshaft. The locking tang of the connecting rod cap must be toward the camshaft side of the cylinder block.

Install the connecting rod caps and the capscrews.

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The connecting rod has changed on the 1994 Certification Level engine to accommodate the increased loading of the articulated pistons. The torquing procedure for the connecting rod capscrews has also changed. The new torque specification is 129 N•m [95 ft-lb] plus 60 degrees ± 5 degrees.

To facilitate this new torquing procedure, the torque angle socket gauge, Part Number 3824520, was developed.

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The torque angle socket is marked with a zero (start) point, a specification window, and a out of limits (OOL) line.

 
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The tightening procedure is to pre-tighten both of the capscrews 129 N•m [95 ft-lb].

With the socket on the capscrew, draw a line from the zero (start) point across the capscrew head to a point on the rod cap.

This line is the gauge line for the angle portion of the specification (60 degrees ± 5 degrees).

 
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With the zero point on the socket gauge aligned with the mark on the capscrew head, tighten the capscrew.

Torque Value:  278  n.m  [205 ft-lb]

With the socket gauge in position, check to see if the fixed mark (on rod cap) is within the window of the gauge.

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If the fixed line is between the “0” line and the “Out Of Line (OOL)” line, tighten or loosen until it is within the window.

If the fixed line is past the “OOL” line, replace the capscrew and repeat the tightening sequence.

 
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Measure the connecting rod side clearance. The side clearance must be between 0.140 mm [0.0055-inch] and 0.33 mm [0.013-inch].

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.

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Finishing Steps

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 CAUTION 

The lubricating oil system must be primed before operating the engine after any internal engine repairs to reduce the possibility of internal component damage. Do not prime the system from the bypass filter; the filter will be damaged.
  • Install the piston cooling nozzles. Refer to Procedure 001-046.
  • Install the lubricating oil pan. Refer to Procedure 007-025.
  • Install the cylinder heads. Refer to Procedure 002-004.
  • Install the push tubes. Refer to Procedure 004-014.
  • Install the rocker lever housings. Refer to Procedure 003-013.
  • Install the rocker lever assemblies. Refer to Procedure 003-009.
  • Install the injectors. Refer to Procedure 006-026.
  • Adjust the valves and injectors. Refer to Procedure 003-004.
  • Install and adjust the compression brakes, if equipped. Refer to Procedure 020-001.
  • Install the rocker lever covers. Refer to Procedure 003-011.
  • Prime the lubricating system. Refer to Procedure 007-037.
  • Fill the engine with lubricating oil. Refer to Procedure 007-025.
  • Fill the cooling system. Refer to Procedure 008-018.
  • Operate the engine until it reaches a temperature of 82°C [180°F], and check for leaks.

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Last Modified:  06-May-2005