The turbo remanufacturing industry survives and thrives due to the availability of old core, which keeps the repair cycle going. Here, Antony Collins from Melett’s Technical Team explains everything you need to know about the quality and importance of old core.

Old core is a previously used turbocharger that can be used as spare parts to be repaired or remanufactured.

During the turbo remanufacturing process, the old core is disassembled and assessed for damage, with the aim of salvaging those parts with little or no wear/damage. Once done, the unsuitable items are replaced with new components and the turbocharger rebuilt to OE standards and specifications. By remanufacturing, it’s possible to achieve a lower-cost alternative to new units while delivering significant benefits to the environment.

Surcharges are often associated with turbo remanufacturing. These are incentives used to ensure the old core is returned – which helps keep the repair cycle going. When a turbo remanufacturer has the turbo core in stock, they can provide the customer with an efficient and less time-consuming service. With a steady influx of old cores, remanufacturers are able to hold stocks of rebuilt turbochargers so that customers do not have to wait for their failed units to be repaired.

There are different grades of old core – the higher the quality, the higher the cost. The grade of old core used can greatly impact the time taken to remanufacture the turbocharger and the number of parts that can be salvaged and reused. The price of old core can also vary broadly depending on the turbocharger model and availability.

Turbo Tip – The lower the quality of old core you purchase; the more time, care and remanufacturing work will be required.

Good quality old core dealers will grade the old core they have available and will explain the potential risks of using a certain, lower quality grade of the core. Each core supplier will have its own grading system, but they all provide an indication of quality. For example:

1. Good core unit – all parts show little or no signs of damage/ wear
2. Good core unit with a bad actuator or, a good actuator with play within rotor assembly
3. Damage to one of the critical components (Actuator, Shaft & Wheel, Compressor Wheel)
4. Damage to more than one of the critical components (Actuator, Shaft & Wheel, Compressor Wheel)
5. Good Actuator and one good end-housing (Compressor Housing or Turbine Housing)
6. Only one good end-housing (Compressor Housing or Turbine Housing)

It is important to remember that old core is a previously used turbocharger. Time and care must be taken to fully analyse each component within the old core.

The use of good grade old core is important as sometimes you cannot see the damage to the components within. It is only when they are cleaned and inspected that you can really assess the condition of the individual components. Here are some of the ways you can examine each component:

1. Clean the components – any defects in the components will be more visible
2. Analyse the component profile – pay attention to detail, have the components warped in any way?
3. Check the sealing surfaces – especially turbine housing to bearing housing surfaces – are they cracked, corroded or warped?

When there is a shortage of good quality old core, it can lead to remanufacturers using a poor grade of old core, which in turn leads to extra costs and resources. Low quality cores often require additional remanufacturing or machining processes, such as grinding the shaft or honing the bearing housing. All this adds to the cost of the turbo repair.

If good quality core is unavailable, it is often more economical to supply a new turbocharger. Melett has a range of complete turbocharger units, covering a wide variety of popular applications, which can be used when a good quality core is unavailable to remanufacture. This allows the repair cycle to continue, reduces turnaround times, and ensures customer expectations can be met.

To find out more about old core suppliers – check out Melett’s website: https://www.melett.com/technical/turbo-repair/old-core-suppliers/