Why Diesel Pro Power Charges a Core Charge for the Detroit Diesel 6-71 Bypass Blower

Detroit Diesel engines are known for their long life, durability, and rebuild-friendly design, and the 6-71 is one of the most iconic among them. For decades, these engines have powered commercial vessels, tugboats, generators, trucks, and countless industrial applications. One of the most important components on these two-stroke engines is the bypass blower, which supplies the scavenging air essential for combustion.

When purchasing a rebuilt or remanufactured 6-71 bypass blower, customers will notice a core charge. This sometimes raises questions — but the practice is standard across the industry and essential for keeping Detroit Diesel parts reliable, available, and affordable.

Below is a clear explanation of why Diesel Pro Power charges a core charge, how the program works, and why it ultimately benefits the customer.

To Return Your 6-71 Bypass Blower Core Be Sure To Fill Out A Return Of Goods Authorization Form 

The Role of the Bypass Blower in the 6-71

Before discussing the core charge, it’s important to understand the part itself.

Detroit Diesel’s two-stroke engines cannot draw in fresh air on their own the way four-stroke engines do. Instead, they rely on a Roots-type bypass blower to:

• Push fresh air into the cylinders
• Remove exhaust gases
• Maintain scavenging pressure
• Support clean, complete combustion
• Deliver predictable power under load

If the blower fails or becomes worn, the engine loses power, smokes excessively, runs hot, and can suffer internal damage. Maintaining a healthy bypass blower is crucial for any Detroit Diesel 6-71.

Because of the blower’s precision machining and heavy-duty construction, the housing and major internals are usually rebuildable — which is where the core charge comes in.

Why Diesel Pro Power Charges a Core Charge

1. To Recover Rebuildable OEM Housings and Components

The blower housings, rotors, and shafts on Detroit Diesels are no longer manufactured in large volumes, especially for older 71-series engines. High-quality replacement housings are limited, which makes the return of used cores essential.

A rebuildable core provides:

• An OEM housing
• Rotor assemblies
• End plates
• Gear drives
• Internal surfaces that can be remachined to factory tolerances

Without the return of these used units, the supply of genuine-fit components would quickly run out.

The core charge ensures customers send their old blower back, so it can be rebuilt and placed back into circulation.

2. To Maintain Availability for Future Customers

Every returned core becomes the foundation for a future rebuilt blower. Without cores, rebuilt inventory disappears — and replacements would become extremely expensive or impossible to source.

The core system allows Diesel Pro Power to:

• Keep rebuilt Detroit blowers in stock
• Maintain fast shipping
• Ensure stable pricing
• Support long-term parts availability

For older engines like the 6-71, consistent availability is a real challenge in the industry. Core programs keep the ecosystem alive.

3. To Hold Down the Cost of Rebuilt Blowers

Brand-new blower housings and rotor assemblies, if available at all, are extremely costly due to low production volume. Rebuilt units cost significantly less because the backbone of the blower — the core — is being reused.

Returning your core reduces the part’s net price because:

• Diesel Pro Power can reuse the housing
• Rotor assemblies and shafts can be remanufactured
• Machining costs are reduced compared to fully new production
• Less raw material and manufacturing time is required

If cores weren’t returned, rebuilt units could cost thousands more due to sourcing or manufacturing new housings.

The core charge essentially says:
Return the old unit and pay the lower price. Keep the old unit and pay the higher price.

4. To Ensure Only Rebuildable Parts Enter the System

The core charge is refundable only if the returned unit is rebuildable. This is important.

Detroit Diesel blowers must pass strict inspections before being used again. Returned cores must not have:

• Cracked housings
• Severely damaged rotors
• Broken gear drives
• Major internal scoring
• Fire damage
• Corrosion beyond machining limits

The core charge motivates customers to return viable cores. If a core is damaged beyond use, it cannot be rebuilt — and Diesel Pro Power must source another housing at much higher cost. The refundable core charge covers this risk.

5. To Support Professional Rebuild Quality

Diesel Pro Power invests heavily into the machining, surfacing, rebalancing, measuring, and reassembly of blower cores. A proper blower rebuild requires:

• Precision rotor measurement
• End-plate machining
• Gear alignment
• Seal replacement
• Internal clearance checks
• Accurate remachining for proper rotor timing

By returning a core, customers support a continuous supply of rebuildable units, which ensures Diesel Pro Power can continue providing professionally rebuilt blowers rather than low-quality or mismatched aftermarket alternatives.

How the Core Charge Benefits the Customer

Even though a core charge appears as an added cost upfront, it actually benefits the buyer in multiple ways:

• You receive a rebuilt blower at a lower price.
  Returning your core drops the total cost significantly.

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• You help maintain long-term parts availability.
  The market for 6-71 blowers depends on recovered housings.

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• You support OEM-grade rebuilds rather than cheap cast copies.
  Quality remains consistent because cores are original Detroit parts.

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• You avoid the risk of buying low-quality aftermarket housings.
  OEM housings are proven to handle decades of operation.

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• You contribute to a sustainable supply chain.
  Rebuilding is more cost-effective and environmentally efficient than manufacturing new housings.

In short, the core system makes the rebuilt blower program possible.

Conclusion: A Necessary Part of Keeping Detroit Diesels Alive

The core charge on Detroit Diesel 6-71 bypass blowers is not a fee for the sake of a fee — it’s an essential part of keeping high-quality rebuilt parts available for decades-old engines that many operators still rely on today.

By returning your core, Diesel Pro Power can continue:

• Offering rebuilt blowers at the lowest possible price
• Ensuring OEM-grade fit and durability
• Maintaining a stable inventory
• Providing fast turnarounds
• Supporting the long life of Detroit Diesel engines

The core charge system is what makes high-quality rebuilt 6-71 blowers possible — and it ensures that Detroit Diesel operators will continue to have reliable parts for years to come.

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