️ Left Hand vs. Right Hand Oil Pump for Detroit Diesel (6V71, 8V71, 6V92, 8V92) | DIESELPRO.COM

In this video, Diesel Pro Power demonstrates how to correctly identify whether you need a left-hand or right-hand oil pump for your Detroit Diesel two-stroke engine, covering popular models like the 6V71, 8V71, 6V92, and 8V92. This quick and clear guide is a must-watch for anyone rebuilding or replacing an oil pump.

Correct pump orientation is critical for proper oil flow and engine health. Installing the wrong pump can lead to catastrophic engine failure. The key is knowing how to locate the driving gear shaft on the pump:

• If the driving gear shaft is on the left, you have a left-hand oil pump.

• If the driving gear shaft is on the right, you have a right-hand oil pump.

This identification method is consistent across all major two-stroke Detroit Diesel V-engine configurations, helping you avoid costly mistakes during rebuilds or repairs.

What You’ll Learn:

• How to identify oil pump orientation on Detroit Diesel two-stroke engines

• The location of the driving gear shaft on the oil pump

• Differences between left-hand and right-hand oil pump configurations

• Why correct pump orientation matters for engine operation

• How to avoid ordering or installing the wrong pump

This video is perfect for Detroit Diesel rebuilders, mechanics, marine engineers, and operators performing in-frame overhauls or full engine rebuilds.

Shop Detroit Diesel Oil Pumps:

• Right-Hand Oil Pump:
  https://dieselpro.com/detroit-diesel-right-hand-oil-pump

• Left-Hand Oil Pump:
  https://dieselpro.com/detroit-diesel-left-hand-oil-pump

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  In the video below a mechanic removes the oil pump from an old Detroit Diesel 8V71

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  What an Oil Pump Does in a Detroit Diesel 2-Stroke Engine

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  Introduction

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  Detroit Diesel’s famous 2-stroke engines — including the Series 53, 71, 92, and 149 — have powered everything from tugboats and fishing vessels to generators and industrial machines. These engines are known for their unique two-stroke cycle, which provides a power stroke on every crankshaft revolution.

  This means higher firing frequency, more consistent torque, and increased demands on lubrication compared to four-stroke engines. At the center of this demanding lubrication system is the oil pump. Without it, the engine could not survive more than a few seconds under load.

  The oil pump’s job is to supply pressurized oil throughout the engine, ensuring that moving parts remain separated by a protective film of lubricant. This prevents metal-to-metal contact, controls temperatures, cleans internal surfaces, and supports long engine life.

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  The Oil Pump’s Primary Responsibilities

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  The oil pump in a Detroit Diesel 2-stroke engine performs several essential functions:

  • Draws oil from the oil pan (sump) and screens out large contaminants.

  • Pressurizes the oil, creating a flow strong enough to move through narrow bearing clearances and oil passages.

  • Distributes oil throughout the engine, reaching crankshaft bearings, connecting rods, camshaft bearings, rocker arms, and turbochargers.

  • Returns oil by gravity to the sump, completing the cycle.

  Because these 2-stroke engines fire every revolution, internal components operate under continuous heavy loads, making steady oil flow absolutely critical.

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  How the Oil Pump Works

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  Drawing Oil from the Sump

  The process starts in the oil pan, where the pump’s pickup tube is submerged in engine oil. A mesh screen or strainer prevents debris from entering.

  As the engine runs, the oil pump creates suction that draws oil up from the sump. This suction is immediately converted into pressurized flow by the pump’s internal gears or rotors.

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  Pressurizing the Oil

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  Most Detroit Diesel 2-stroke engines use a gear-type oil pump. Inside the pump:

  • Meshing gears trap oil between the teeth and the pump housing.

  • As the gears rotate, oil is carried from the inlet side to the outlet side.

  • When the gears come back together, they force the oil out under pressure.

  This mechanical action generates the steady pressure needed to move oil through the engine, often regulated by a built-in pressure relief valve to avoid over-pressurization.

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  Delivering Oil to the Engine

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  Once pressurized, oil flows into the engine’s main oil gallery — a large drilled passage inside the block. From here, it branches out through smaller drilled passages to all critical areas.

  This system ensures that every vital moving surface receives oil at the right pressure and volume. Typical pressures range from 40 to 70 psi, depending on engine design and load.

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  Lubricating the Crankshaft and Bearings

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  The main crankshaft bearings are the first major recipients of oil. Here’s how it works:

  • Oil flows from the main gallery into the bearing saddles that support the crankshaft.

  • It forms a pressurized film between the bearing shell and the spinning crankshaft journal.

  From there, oil flows through drilled holes inside the crankshaft itself, traveling radially to reach the connecting rod journals, where it lubricates the rod bearings. This process:

  • Reduces friction between the crankshaft and bearings.

  • Cushions the rotating mass under explosive combustion loads.

  • Helps carry away heat generated by combustion and friction.

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  Feeding the Camshaft and Gear Train

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  Detroit Diesel 2-stroke engines rely on a camshaft gear train that operates the unit injectors and drives accessories. The oil pump delivers pressurized oil to:

  • Camshaft bearings, reducing friction as the cam rotates.

  • Gear train surfaces, either by direct flow or splash lubrication, ensuring the teeth remain coated with oil.

  This minimizes wear on the gears that synchronize engine operation and reduces noise.

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  Lubricating Rocker Arms and Valves

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  Oil continues upward through passages in the cylinder head to reach the rocker shafts and pushrod assemblies. Here it:

  • Lubricates the pivot points of rocker arms.

  • Coats valve stems and guides, reducing wear.

  • Washes over the valve springs to aid in cooling.

  Any excess oil drains back to the sump by gravity through return passages, completing the cycle.

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  Turbocharger Lubrication

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  any Detroit Diesel 2-stroke applications include a turbocharger, which uses exhaust gases to spin a turbine and compress intake air, increasing engine power.

  Turbochargers can spin at up to 100,000 RPM, generating intense heat. The oil pump provides a dedicated pressurized supply to the turbo bearing housing, where it:

  • Forms a film that supports the high-speed shaft, preventing metal contact.

  • Removes heat from the turbo’s core, helping prevent overheating and oil coking.

  After doing its job, oil drains back to the sump through a large return line, often by gravity.

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  Cleaning and Cooling Functions of Oil

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  The oil pump not only lubricates but also plays a critical role in cleaning and cooling:

  • As oil circulates, it picks up tiny metal particles, soot, and combustion byproducts.

  • It carries them to the oil filter, where contaminants are trapped before clean oil recirculates.

  Oil also absorbs heat from pistons, bearings, and the turbocharger. When it returns to the sump, it releases some of that heat into the surrounding metal or to a dedicated oil cooler, if equipped.

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  Oil Pump Pressure Control

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  Because different engine speeds and loads create different lubrication demands, the oil pump system includes a pressure relief valve. If pressure rises above a set point (often around 70 psi), the valve opens and allows oil to bypass, protecting seals and components.

  This ensures:

  • Steady oil pressure at idle, cruise, or full throttle.

  • Protection against pressure spikes that could rupture gaskets or overload bearings.

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  The Oil Pump’s Role in Overall Engine Life

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  In Detroit Diesel 2-stroke engines, consistent oil delivery is not optional — it’s the backbone of reliability. The oil pump’s role ensures:

  • Prevention of metal-to-metal contact, which otherwise would rapidly destroy bearings and journals.

  • Removal of contaminants, preventing abrasive wear and sludge buildup.

  • Dissipation of excess heat, reducing the risk of seizures and extending engine lifespan.

  Engines with well-maintained oil pumps and regular oil changes routinely exceed tens of thousands of operational hours, especially in marine and industrial environments.

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  Maintenance Considerations

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  Given its importance, the oil pump requires attention during overhauls and periodic inspections. Typical maintenance points include:

  • Checking oil pressure with a mechanical gauge to verify the pump is delivering proper pressure.

  • Inspecting drive gears and shafts for wear or scoring.

  • Ensuring the pickup screen isn’t clogged, which could starve the pump.

  • Replacing or rebuilding the pump during major overhauls to ensure it meets OEM flow and pressure specs.

  A failing oil pump can lead to low oil pressure, bearing damage, and catastrophic engine failure. This is why many operators monitor oil pressure gauges closely and shut down engines at the first sign of trouble.

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  Conclusion

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  In a Detroit Diesel 2-stroke engine, the oil pump does far more than simply move oil. It’s the lifeline of the entire system, ensuring that every critical moving part receives the lubrication it needs to function under extreme pressures and temperatures. It keeps the crankshaft and bearings floating on a protective oil film, lubricates the camshaft and valve train, cools turbochargers, carries away heat, and filters out harmful debris.

  Without the continuous work of the oil pump, these robust two-stroke diesels would not achieve their legendary durability and ability to run hour after hour under heavy loads. Proper oil pump operation and maintenance are fundamental to getting the full service life out of any Detroit Diesel 2-stroke engine.

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