Engine Components and Their Roles (Covering Detroit Diesel 271, 371, 471, 671 Engines)

October 24, 2024

Detroit Diesel 71 Series Inline Engine Component List ( 271, 371, 471, 671)


The Detroit Diesel Series 71 engine is composed of several critical components that work together to drive efficient combustion and ensure the engine’s performance. Below is an in-depth look at each of these components, their function, and how they contribute to the engine’s overall operation. Before you get started there are a few links to look at the parts for each engine type. 


Parts For 71 Series Inline Engines


1) Cylinder Block For Detroit Diesel 71 Series Inline Engines: The Structural Core of the Engine


Detroit Diesel 671 Cylinder Block
Detroit Diesel 671 Cylinder Block

The cylinder block is the most critical structural component of the Detroit Diesel Series 71 engine. It serves as the foundation for the engine’s other parts, housing and supporting key components such as the crankshaft, camshaft, pistons, and cylinder liners. The block is designed to withstand the high pressures and temperatures generated during the combustion process, while also providing structural rigidity to keep moving parts in alignment.


Key Features of the Cylinder Block:


  1. Water Jackets:
  2. Air Box and Scavenging System:
  3. Cylinder Bores and Liners:

Functions of the Cylinder Block:


  • Support and Alignment
  • Heat Dissipation
  • Housing for Moving Parts

Maintenance and Inspection Procedures:


Regular maintenance of the cylinder block is critical to ensuring the engine’s longevity and preventing costly repairs. The following are essential maintenance and inspection tasks for the cylinder block:


  1. Visual Inspection for Cracks and Corrosion
  2. Cylinder Bore and Liner Inspection
  3. Pressure Testing for Cracks in Water Jackets
  4. Cleaning the Block
  5. Bolt and Thread Inspection
  6. Proper Storage

Common Issues and Solutions:


  • Overheating
  • Oil Leaks
  • Warping

2) Cylinder Liners For Detroit Diesel 71 Series Inline Engines: Protecting The Engines Cylinders and Ensuring Longevity


Liner Standard #2 For Detroit Diesel 71 Series Engine
Liner Standard #2 For Detroit Diesel 71 Series Engine

The cylinder liners are a critical component of the Detroit Diesel Series 71 engine, providing a replaceable surface within the cylinder bore where the pistons move. Cylinder liners not only protect the cylinder walls from wear but also contribute to the overall heat dissipation and performance of the engine. By maintaining a smooth, durable surface for the pistons, liners help ensure proper compression, efficient combustion, and long engine life.


Types of Cylinder Liners:


Cylinder liners can be broadly categorized into two types:

  1. Wet Liners:
  2. Dry Liners:

Functions of Cylinder Liners:


  1. Wear Resistance:
  2. Heat Dissipation:
  3. Maintaining Compression:
  4. Lubrication Support:

Maintenance and Inspection of Cylinder Liners:


Regular inspection and maintenance of cylinder liners are critical to extending the life of the engine and avoiding costly repairs. Below are key maintenance practices to follow for cylinder liners:


  1. Visual Inspection for Wear
  2. Measuring Cylinder Liner Wear
  3. Inspecting for Cracks and Pitting
  4. Honing the Cylinder Liner
  5. Replacing Cylinder Liners
  6. Ensuring Proper Fit

Common Symptoms of Worn Cylinder Liners:


  • Loss of Compression
  • Excessive Oil Consumption
  • Coolant Leaks (Wet Liners)

Preventing Liner Wear:


  1. Maintain Proper Lubrication
  2. Coolant System Maintenance
  3. Clean Air Supply

3) Pistons For Detroit Diesel 71 Series Inline Engines: Power Drivers Of The Engine


2 Piece Piston Kit For Detroit Diesel 71 Series Turbo Intercooled Engine
2 Piece Piston Kit For Detroit Diesel 71 Series Turbo Intercooled Engine

The pistons in the Detroit Diesel Series 71 engine play a crucial role in converting the energy from combustion into mechanical motion. Pistons travel up and down inside the cylinder liners, compressing the air-fuel mixture and generating the force needed to drive the crankshaft. Proper maintenance and inspection of the pistons are critical for ensuring engine efficiency and longevity, especially since exact tolerances and measurements are key to keeping these older engines running smoothly.


Key Functions of Pistons:


  1. Compression of Air-Fuel Mixture:
  2. Converting Combustion Energy to Mechanical Motion:
  3. Sealing and Oil Control:

Piston Components:


  1. Piston Crown:
  2. Piston Skirt:
  3. Piston Rings:
    • Compression Rings
    • Oil Control Rings

Piston Materials


Critical Measurements and Tolerances for Pistons:


  1. Piston-to-Cylinder Clearance:
  2. Ring End Gap
  3. Piston Pin Fit
  4. Piston Skirt Clearance

Piston Inspection and Maintenance:


Visual Inspection for Wear and Damage

  1. Measuring Piston Wear
  2. Piston Ring Replacement:
  3. Cleaning Pistons

Piston Replacement and Installation


  1. When to Replace Pistons
  2. Installation of New Pistons

Common Symptoms of Piston Problems


  • Loss of Compression
  • Excessive Oil Consumption
  • Piston Slap

4) Crankshafts For Detroit Diesel 71 Series Inline Engines: Converting Linear Motion Into Rotational Power


Crankshaft For Detroit Diesel 671 Engine
Crankshaft For Detroit Diesel 671 Engine

The crankshaft is one of the most critical components of the Detroit Diesel Series 71 engine. It converts the up-and-down (linear) motion of the pistons into rotational motion that powers the engine’s drivetrain. The crankshaft operates under intense pressure and stress, and its ability to function properly is essential for overall engine performance. Proper maintenance and inspection are key to ensuring the crankshaft remains in good condition.


Key Functions of the Crankshaft:


  1. Converting Linear to Rotary Motion:
  2. Bearing Support:
  3. Connecting Rod Journals:
  4. Counterweights:

Crankshaft Components:


  1. Main Journals:
  2. Connecting Rod Journals (Crank Pins):
  3. Thrust Bearings:
  4. Oil Passages:

Critical Tolerances and Measurements for the Crankshaft:


  1. Main Bearing Journal Clearance:
  2. Connecting Rod Journal Clearance:
  3. Crankshaft End Play (Axial Clearance):
  4. Crankshaft Runout:

Crankshaft Inspection and Maintenance:


  1. Visual Inspection for Cracks and Wear:
  2. Measuring Journal Wear:
  3. Polishing or Machining the Crankshaft:
  4. Inspecting the Crankshaft Oil Passages:
  5. Replacing Bearings:
  6. Checking for Proper Thrust Bearing Clearance:

Crankshaft Removal and Installation:


  1. Removing the Crankshaft:
  2. Installing the Crankshaft:

Common Symptoms of Crankshaft Problems:


  1. Vibration
  2. Knocking or Tapping Sounds
  3. Low Oil Pressure
  4. Excessive End Play

 

5) Connecting Rods For Detroit Diesel 71 Series Inline Engines: Transmitting Power From Pistons To Crankshaft


Connecting Rod For Detroit Diesel 71 Series Inline Engines With 1 Piece Pistons
Connecting Rod For Detroit Diesel 71 Series Inline Engines With 1 Piece Pistons

The connecting rods play a crucial role in the operation of the Detroit Diesel Series 71 engine. They connect the pistons to the crankshaft, transmitting the force generated by the combustion process to the crankshaft, which then converts this force into rotational power. Connecting rods must withstand significant stress, heat, and pressure, so ensuring their integrity is critical to the engine’s performance and longevity.


Key Functions of Connecting Rods:


  1. Transmitting Combustion Force
  2. Supporting Piston Movement

Components of Connecting Rods:


  1. Small End
  2. Big End
  3. Connecting Rod Bearings Cap and Bolts

Critical Tolerances and Measurements for Connecting Rods:


  1. Rod Bearing Clearance
  2. Small End Bushing Clearance
  3. Rod Length and Alignment
  4. Connecting Rod Bolt Torque

Connecting Rod Inspection and Maintenance:


  1. Visual Inspection for Wear and Damage
  2. Measuring Bearing Wear
  3. Checking for Rod Alignment
  4. Small End Bushing Inspection
  5. Lubrication

Connecting Rod Removal and Installation:


  1. Removing the Connecting Rods
  2. Installing the Connecting Rods

Common Symptoms of Connecting Rod Problems:


  1. Knocking or Tapping Sounds
  2. Vibration or Excessive Wear
  3. Low Oil Pressure
  4. Piston Damage

6) Camshaft For Detroit Diesel 71 Series Inline Engines : Controlling Valve Timing & Engine Operation


Detroit Diesel 271 Camshaft
Detroit Diesel 271 Camshaft

The camshaft is a critical component of the Detroit Diesel Series 71 engine, responsible for controlling the precise timing of the intake and exhaust valves. This timing is essential for ensuring efficient combustion and overall engine performance. The camshaft, through its lobes and gears, coordinates the opening and closing of the valves, allowing the engine to maintain proper air intake and exhaust expulsion during the two-stroke combustion cycle.


Key Functions of the Camshaft:


  1. Controlling Valve Timing:
  2. Coordinating Engine Timing:
  3. Driving Fuel Injectors (if applicable):

Below is a video of a camshaft being installed into a Detroit Diesel 671 Long Block



Components of the Camshaft


  1. Camshaft Lobes
  2. Camshaft Bearings
  3. Camshaft Timing Gear

Critical Tolerances and Measurements for the Camshaft


  1. Camshaft Lobe Height
  2. Camshaft Journal Clearance
  3. Camshaft End Play (Axial Clearance)
  4. Camshaft Runout

Camshaft Inspection and Maintenance


  1. Visual Inspection for Wear and Damage
  2. Measuring Camshaft Lobe Wear
  3. Checking Camshaft Bearings
  4. Inspecting the Camshaft Timing Gear
  5. Lubrication and Oil Passages

Camshaft Removal and Installation


  1. Removing the Camshaft
  2. Installing the Camshaft
  3. Torquing the Camshaft Bearings

Common Symptoms of Camshaft Problems


  1. Poor Engine Performance
  2. Knocking or Tapping Noises
  3. Oil Pressure Issues
  4. Timing Issues

7) Cylinder Head For Detroit Diesel 71 Series Inline Engines: The Heart Of 71 Series Inline Engine Efficiency


The cylinder head is a critical component in the operation of the Detroit Diesel 71 Series Inline Engines—which include the 271, 371, 471, and 671 models. Its role in housing essential components like the exhaust valves and fuel injectors, as well as managing airflow and cooling, makes it the centerpiece of engine functionality. Proper maintenance and knowledge of the cylinder head’s structure and operation are vital for keeping these engines in good working condition, especially given that the official service manual for these engines is no longer in print.


Key Functions of the Cylinder Head: The cylinder head in the 71 Series inline engines performs several essential functions:


  • Sealing the Combustion Chamber
  • Housing for Components
  • Cooling
  • Directing Airflow

Components of the Cylinder Head


Below is a video of a Cylinder head being installed onto a Detroit Diesel 671.



  1. Exhaust Valves

  2. Fuel Injectors
  3. Valve and Injector Operating Mechanism
  4. Valve Seat Inserts
  5. Injector Tubes
  6. Water Nozzles and Coolant Passages
  7. Manifolds
  8. Compression Gaskets & Seals

Critical Tolerances & Measurements:


  1. Valve Clearances
  2. Flatness of the Cylinder Head’s Fire Deck
  3. Injector Tube Fitment
  4. Valve Seat Alignment

Inspection & Maintenance:


  1. Regular Valve Adjustment
  2. Cooling System Maintenance
  3. Injector Tube Inspection
  4. Gasket and Seal Inspection
  5. Check for Cracks or Warping

Common Symptoms of Cylinder Head Problems:


  1. Overheating
  2. Loss of Compression
  3. Coolant in Oil or Oil in Coolant
  4. Excessive Exhaust Smoke
  5. Sticking Valves

8)  Valves For Detroit Diesel 71 Series Inline Engines: Regulating Exhaust Flow


U-Valve For Detroit Diesel 71 Series Inline Engines
U-Valve For Detroit Diesel 71 Series Inline Engines

In the Detroit Diesel Series 71 engine, the primary airflow into the cylinders is controlled by the blower, which forces fresh air into the combustion chambers. The engine operates on a two-stroke cycle, and while there are no traditional intake valves, the exhaust valves play a crucial role in expelling exhaust gases after combustion. Proper valve function is essential for efficient scavenging and maintaining the engine’s overall performance.

 


Key Functions of the Exhaust Valves:


  1. Exhaust Expulsion
  2. Sealing the Combustion Chamber
  3. Supporting the Scavenging Process:

Components of the Exhaust Valves:


  1. Valve Head
  2. Valve Stem
  3. Valve Seat
  4. Valve Springs
  5. Valve Guides

Critical Tolerances and Measurements for Exhaust Valves:


  1. Valve Stem-to-Guide Clearance:
  2. Valve Seat Width:
  3. Valve Face Angle:
  4. Valve Spring Tension:

Exhaust Valve Inspection and Maintenance:


  1. Visual Inspection for Wear and Damage
  2. Valve Face and Seat Grinding
  3. Valve Stem Wear Measurement
  4. Replacing Valve Springs
  5. Valve Guide Lubrication

Valve Removal and Installation:


  1. Removing the Exhaust Valves:
  2. Installing the Exhaust Valves:
  3. Adjusting Valve Clearance:

Common Symptoms of Exhaust Valve Problems:


  1. Loss of Compression
  2. Excessive Oil Consumption
  3. Knocking or Tapping Sounds

9) Fuel Injectors For Detroit Diesel 71 Series Inline Engines: Delivering Fuel For Precise Combustion


N60 Injector Commonly Used In Detroit Diesel 71 Series Inline Engines
N60 Injector Commonly Used In Detroit Diesel 71 Series Inline Engines

The fuel injectors in the Detroit Diesel Series 71 engine are responsible for delivering the correct amount of fuel to each cylinder at precisely the right time. In this two-stroke diesel engine, the injectors must operate with exact timing and precision to ensure efficient combustion and optimal engine performance. Proper maintenance of the injectors is critical to avoiding fuel delivery issues, power loss, or excessive fuel consumption.


Key Functions of the Fuel Injectors:


  1. Atomizing Fuel:
  2. Timed Delivery:
  3. Regulating Fuel Quantity:
  4. High-Pressure Delivery:

Below is a video of injectors and fuel lines being installed into a Detroit Diesel 671 Long Block



Components of the Fuel Injectors


  1. Injector Nozzle
  2. Plunger
  3. Injector Body
  4. Injector O-Rings

Critical Tolerances and Measurements for Fuel Injectors:


  1. Injector Nozzle Spray Pattern
  2. Plunger-to-Barrel Clearance
  3. Injector Opening Pressure
  4. Injector Timing

Fuel Injector Inspection and Maintenance


  1. Visual Inspection for Leaks and Damage
  2. Testing the Injector Spray Pattern
  3. Cleaning the Injectors
  4. Checking Injector Timing
  5. Plunger and Barrel Wear Inspection
  6. Replacing Worn or Damaged Injectors

Fuel Injector Removal and Installation


  1. Removing the Fuel Injectors
  2. Installing the Fuel Injectors
  3. Bleeding the Fuel System
  4. Adjusting Injector Timing After Installation

Common Symptoms of Fuel Injector Problems


  1. Hard Starting or Misfires
  2. Excessive Fuel Consumption
  3. Black Smoke from the Exhaust
  4. Loss of Power

9) Blower For Detroit Diesel 71 Series Inline Engines: The Key To Efficient  Airflow In The 71 Series Inline Engines


Detroit Diesel 471 Blower
This is a picture of a Detroit Diesel 471 right hand Blower. This is a key component for air intake that makes the 2-Cycle system possible.

In the Detroit Diesel 71 Series Inline Engines—which include the 271, 371, 471, and 671 models—the blower plays a critical role in the engine’s two-stroke operation. It ensures proper airflow into the cylinders, which is essential for both combustion and scavenging. Proper understanding and maintenance of the blower system are key to maintaining engine efficiency and avoiding performance issues. Since the official service manual for these engines is no longer in print, making this information available is crucial for engine owners and mechanics alike.


Key Functions of the Blower: The blower in the 71 Series engines performs several essential tasks:

  • Supplying Combustion Air
  • Scavenging Exhaust Gases
  • Maintaining Efficient Airflow

Components of the Blower:

  1. Blower Casing
  2. Blower Drive Gear
  3. Air Intake System
  4. Air Box
  5. Air Inlet Ports
  6. Blower Seals and Gaskets

Critical Tolerances & Measurements:


  1. Blower Air Clearance
  2. Blower Drive Gear Alignment
  3. Air Box and Inlet Port Condition
  4. Blower Seals

Inspection & Maintenance:


  1. Regular Inspection for Blockages
  2. Check the Blower Drive Gear
  3. Seal and Gasket Maintenance
  4. Air Box Drains
  5. Blower Bearings

Common Symptoms of Blower Problems:


  1. Reduced Engine Power
  2. Excessive Exhaust Smoke
  3. High Engine Temperatures
  4. Unusual Noises from the Blower
  5. Oil in the Air Box

10) Oil Pump For Detroit Diesel 71 Series Inline Engines: Ensuring Proper Lubrication Throughout The Engine


Right Hand Oil Pump - Used In Detroit Diesel 371, 471, and 671 Engines
Right Hand Oil Pump – Used In Detroit Diesel 371, 471, and 671 Engines

The oil pump in the Detroit Diesel Series 71 engine plays a crucial role in ensuring that all moving components of the engine are properly lubricated. By circulating oil under pressure, the oil pump minimizes friction between moving parts, helps maintain engine temperature, and ensures that the engine runs smoothly and efficiently. Proper maintenance of the oil pump is essential for preventing engine wear, overheating, or catastrophic failure due to insufficient lubrication.


Key Functions of the Oil Pump:


  1. Circulating Engine Oil
  2. Maintaining Oil Pressure
  3. Heat Dissipation
  4. Filtering Contaminants:

Components of the Oil Pump:


  1. Pump Gears
  2. Pump Housing
  3. Relief Valve
  4. Oil Pickup Tube

Critical Tolerances and Measurements for the Oil Pump:


  1. Oil Pump Gear Clearance
  2. Pump Gear End Play
  3. Oil Pressure Specifications
  4. Relief Valve Opening Pressure

Oil Pump Inspection and Maintenance:


  1. Visual Inspection for Wear and Damage:
  2. Checking Oil Pressure:
  3. Relief Valve Function Testing
  4. Checking the Oil Pickup Tube
  5. Oil Pump Gear Wear:

Oil Pump Removal and Installation:


  1. Removing the Oil Pump
  2. Installing the Oil Pump
  3. Priming the Oil Pump
  4. Testing Oil Pressure After Installation

Common Symptoms of Oil Pump Problems:


  1. Low Oil Pressure
  2. Overheating
  3. Oil Leaks
  4. Unusual Engine Noise

11) Turbocharger For Detroit Diesel 71 Series Inline Engines: Boosting Engine Power By Increasing Air Intake


Turbo Used In High Horsepower Marine (Aftercooled) Detroit Diesel 671 Engines
Turbo Used In High Horsepower Marine (Aftercooled) Detroit Diesel 671 Engines

The turbocharger in the Detroit Diesel Series 71 engine is designed to increase the engine’s efficiency and power by forcing more air into the combustion chamber. This extra air allows for more fuel to be burned during combustion, resulting in greater power output. Proper maintenance of the turbocharger is essential to ensure optimal engine performance, reduce emissions, and prevent engine damage caused by insufficient airflow.


Key Functions of the Turbocharger:


  1. Increasing Airflow to the Engine
  2. Utilizing Exhaust Gases
  3. Enhancing Combustion Efficiency
  4. Cooling the Intake Air

Components of the Turbocharger:


  1. Turbine Housing and Wheel
  2. Compressor Housing and Wheel
  3. Shaft and Bearings
  4. Wastegate (If Equipped)
  5. Intercooler (If Equipped)

Critical Tolerances and Measurements for the Turbocharger:


  1. Shaft End Play (Axial Clearance)
  2. Shaft Radial Clearance
  3. Turbine and Compressor Wheel Clearance
  4. Boost Pressure

Turbocharger Inspection and Maintenance:


  1. Visual Inspection for Damage
  2. Checking Shaft Play
  3. Cleaning the Turbocharger
  4. Inspecting and Replacing Bearings
  5. Wastegate Testing (If Equipped)
  6. Oil Supply Inspection

Turbocharger Removal and Installation:


  1. Removing the Turbocharger
    • Inspection After Removal
  2. Installing the Turbocharger
  3. Priming the Turbocharger
  4. Testing Boost Pressure After Installation

Common Symptoms of Turbocharger Problems:


  1. Loss of Power
  2. Excessive Smoke from the Exhaust
  3. High Boost Pressure
  4. Unusual Noises

 

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