1. Cylinder Bore and Piston Dimensions

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• 11.1L: Smaller bore and stroke, requiring different piston diameters, liner dimensions, and torque specifications for connecting rod and cylinder head bolts.
  • Bore Diameter: 4.921–4.922 inches.
  • Liner Protrusion: 0.001–0.004 inches.
    

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• 12.7L: Standard bore size common across many Series 60 models.
  • Bore Diameter: 4.921–4.927 inches.
  • Liner Protrusion: 0.001–0.004 inches.
    

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• 14L: Larger bore and stroke, with heavier pistons and longer connecting rods. This impacts liner dimensions and piston clearances.
  • Bore Diameter: 5.118–5.120 inches.
  • Liner Protrusion: 0.001–0.005 inches.

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2. Crankshaft and Connecting Rod Differences

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• 11.1L: Uses a smaller crankshaft and lighter connecting rods due to reduced displacement.
  • Main Journal Diameter: 3.186–3.188 inches.
  • Rod Journal Diameter: 2.998–3.000 inches.
  • Rod Bearing Clearance: 0.001–0.003 inches.
    

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• 12.7L: Shares similar crankshaft dimensions and bearing tolerances with the 11.1L engine, but has longer connecting rods to accommodate the increased stroke.
  • Rod Length: Slightly longer than 11.1L rods.
    

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• 14L: Features a heavier, longer crankshaft and larger connecting rods to handle increased torque and power output.
  • Main Journal Diameter: 3.425–3.427 inches.
  • Rod Journal Diameter: 3.346–3.348 inches.
  • Rod Bearing Clearance: 0.002–0.004 inches.

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3. Cylinder Head and Valve Train Components

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• Valve Sizes: Larger valves in the 14L engine for improved airflow.
  • 11.1L Valve Stem-to-Guide Clearance:
    • Intake: 0.001–0.003 inches.
    • Exhaust: 0.002–0.004 inches.
      

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  • 12.7L and 14L Valve Stem-to-Guide Clearance:
    • Intake: 0.002–0.004 inches.
    • Exhaust: 0.003–0.005 inches.
      

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• Camshaft Differences:
  • 11.1L: Smaller camshaft journals and lobes.
  • 12.7L: Standard camshaft dimensions for general applications.
  • 14L: Larger camshaft lobes and journals to accommodate increased valve lift and duration.

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4. Timing Components

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• Timing Gear Lash:
  • All three engines maintain similar gear lash specifications: 0.002–0.009 inches.
  • However, the 14L timing gears are typically larger and may require different shimming during alignment.
    

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• Camshaft Timing Marks:
  • Procedures for aligning timing marks are identical, but the position of marks may vary slightly due to different gear configurations.

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5. Torque Specifications

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Torque specifications differ due to component size and material differences:

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• Cylinder Head Bolts:
  • 11.1L: Torque to 180 lb-ft, then turn 90°.
  • 12.7L: Torque to 200 lb-ft, then turn 90°.
  • 14L: Torque to 220 lb-ft, then turn 90°.
    

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• Main Bearing Bolts:
  • 11.1L: Torque to 135 lb-ft, then turn 90°.
  • 12.7L: Torque to 150 lb-ft, then turn 90°.
  • 14L: Torque to 175 lb-ft, then turn 90°.

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6. Oil and Coolant Capacities

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• 11.1L: Smaller oil pan and coolant passages.
  • Oil Capacity: ~32 quarts.
  • Coolant Capacity: ~48 quarts.
    

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• 12.7L: Standard capacity for medium-duty applications.
  • Oil Capacity: ~38 quarts.
  • Coolant Capacity: ~54 quarts.
    

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• 14L: Larger oil pan and cooling system to handle increased heat generation.
  • Oil Capacity: ~45 quarts.
  • Coolant Capacity: ~60 quarts.

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7. Application-Specific Adjustments

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The 11.1L is often used in lighter-duty applications, while the 14L is designed for heavy-duty applications requiring higher torque and power. These differences affect:

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• Accessory drive components (e.g., air compressors, alternators).
• Turbocharger size and mounting.
• Flywheel and flywheel housing designs.
  

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  Parts Catalog for Cummins 11.1L Marine Engine

  Parts Catalog for Cummins 12.7 L Marine Engine

  Parts Catalog for Cummins 14L Marine Engine