“Reconditioning” Must Mean More Than to “Put Into Good Shape Again”

Component reconditioning is very popular

Component reconditioning has many advantages. This is especially true in case of large, heavy components:

  • Reconditioning usually represents a cost saving of 50 – 70% compared to replacement
  • Reconditioning a component nearly always takes up significantly less time than fabricating a new one
  • Long lead times or supply chain crunches are less of an issue, as supply chains are shorter and simpler
  • No new part might be available when one is needed. To reduce risk and stock keeping costs, OEMs manufacture and sell spare parts for ever shorter time periods only.
  • Reconditioning results in a smaller carbon footprint than replacement

Given these advantages, it is hardly surprising that component reconditioning has been widely used for many years in industries such as marine and power generation, where components are large and where equipment life is long.

But, what does reconditioning actually mean?

Dictionaries and thesauri usually equate the word “reconditioning” with “to put into working order again” or “to put back in shape”. Proposed synonyms are: To fix, mend, patch, renovate, repair and revamp.

This implies that the goal of the reconditioning process is to put the component back into the state it was before it got worn or damaged.

At QuantiServ, we are convinced that we should do much more than to put a component back into its original, unworn condition. We set the bar much higher for ourselves. After all, we are one of the largest reconditioning companies in our industry and we have in-house research and development resources, that enable us to continuously push  the technology envelope. Noblesse oblige, as the French proverb goes.

We believe that whenever a machinery component undergoes reconditioning at one of our four reconditioning centres, we are presented with an opportunity to not just put the part back to its original condition, but to improve on it. We habitually apply new technologies, modern materials and advanced processes to improve component design, leading to a better performance and extended Time Between Overhaul (TBO).

This sets us apart from all the low-cost reconditioning companies. These companies return to their customers components that – in the best of cases – perform as good as when they were new, but never better. Unfortunately, by so doing, these companies forego customer value by providing sub-optimal service.

There are many good examples of how we have lived up to our high standards and have engineered, manufactured and delivered to our customers improved components that have subsequently shown superior performance. An illustrative example comes from a power plant in the Caribbean, that suffered from very short TBOs. Pistons on these 90-bore engines had to be pulled every 3’000 running hours, to replace piston rings, pistons and, sometimes, even cylinder liners. To solve the problem of such unacceptably short maintenance intervals and component life-times, we have thoroughly analyzed and then redesigned some components of this 90-bore, two-stroke engines. Specifically, we have altered the number of piston rings, have coated the piston ring grooves with our QS50K material and have applied a coating to the piston skirts.

The result of these modification is that the TBO could be increased from 3’000 hours to 18’000 hours!

Three piston rings instead of five

In internal combustion engines, piston rings seal the combustion chamber. While the piston rings’ purpose is unambiguous, it is less clear how many piston rings are required, to get the job done effectively. Historically, four or five piston rings per cylinder were deemed necessary on low-speed, two-stroke diesel engines. Simulations and field experience collected by us in recent years has shown that on many engine types, pistons with only three or four piston rings perform better than those with five. “Less is more”, when it comes to piston ring tribology.

Anti-friction coated piston skirts

A well performing forced piston cooling system is essential, especially on engines that operate on heavy fuel oil (HFO) to maintain a relatively low and stable core temperature. If the piston temperature rises above a critical threshold, then galling, scuffing or seizing will occur due to thermal expansion and breakdown of the oil film between the piston and cylinder liner.

The performance racing industry has been using coated pistons for some time already for this very reason. These so-called anti-friction coatings, that are applied to the piston skirts, are essentially dry film lubricants with a very low friction coefficient. This results in low friction forces and a reduction of parasitic drag, while also decreasing heat saturation in the piston skirt and core.

A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and with an anti-friction piston skirt
A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and anti-friction piston skirt

Anti-friction coatings offer the following benefits:

  • They act as a thermal barrier coating and reduce metal-to-metal contact
  • They increase component life time and TBO due to a lower wear rate
  • Reduced friction (a parasitic loss) results in a lower fuel consumption
  • They support oil film formation and therefore reduce the risk of galling, scuffing and seizing, particularly under challenging operating conditions such a running-in, high load operation and load changes

QS50K pistons

An excellent example of us improving engine component design is the development of our QS50K pistons. From a few years ago, many customers reported excessive wear in the piston ring grooves. The customers informed us that pistons with chromium plated ring grooves, which has been the industry standard for decades, would only last for a few thousand running hours. As reported this applied, in equal measure, to new as well as to reconditioned pistons and to many different engine types.

Our engineering and development colleagues started to investigate. They eventually developed an entirely new process of coating the piston ring grooves. They replaced the chromium in the ring grooves with a very advanced, proprietary material formula which has been proven to easily last for 20’000 hours and more. The successful development and market introduction of the patented QS50K coating process is a good example of how QuantiServ developed a solution to problems reported to us by our customers.

Since its introduction, more than one thousand QS50K pistons have entered service. The earliest ones have meanwhile accumulated well beyond 30’000 running hours!

Do talk to us if you have a specific problem with your installation. If machine uptime or performance is lower than it should be, if components wear out too fast, or if they fail prematurely. It is quite possible that we a solution available – perhaps we have already solved a similar problem for another customer. And if we do not have a tried and tested solution ready, then we will be happy to investigate and look for one.

In the case of the Caribbean Power Plant we have also supplied special piston rings that the engine OEM does not have in his portfolio for this engine type. This, in addition to implementing the modifications described above.


Our Reconditioning Offering


QuantiServ’s enduring commitment towards resource reduction and sustainability is demonstrated by our membership in the Association for Sustainable Manufacturing (MERA). We proudly carry MERA’s Manufactured Again Certification Mark, which is a recognizable symbol
that represents the quality, value and sustainability of our processes.

Image Gallery

Example of anti-friction coating on 90-bore piston skirts in our reconditioning centre in Kruiningen, in the Netherlands. Once the anti-friction coating is applied, the piston skirts get cured in an oven. As is usually the case, reconditioning of these piston skirts included the replacement of the four bronze bandages.

A 90-bore two-stroke engine piston with three piston ring grooves (instead of five) and with an anti-friction piston skirt

Nuclear Power Plant Emergency Diesel Generator Block Repair

The operational requirements for emergency diesel generators (EDG) installed in nuclear power plant are very strict and demanding. In case of an emergency event leading to the loss of off-site power, a nuclear power plant’s EDGs are meant to supply independent, redundant power. From this follows that they have to start reliably and quickly  under any condition and must be able to take on load almost instantaneously, which generally means within about 10 Seconds. This is tested regularly under real-life conditions, according to the prevailing nuclear codes, standards and regulations.

This testing regimen of sudden load changes puts an enourmous thermal loading on most of the EDG’s internal components and on its auxiliary systems. Excessive wear and tear is therefore to be expected and is indeed a small price to pay for ensuring plant safety.

For years, QuantiServ has been supporting nuclear power plant operators and contractors serving them with specialist services throughout the long service life of the plants. We are happy to play a small, but nevertheless important role in ensuring safe and reliable electricity supply from whatever source.

The enclosed pictures show the machining of an impressively large, 20-cylinder engine with a rated output of 4000 kw, a cylinder bore of 240 mm and a stroke of 230 mm. It suffered from a small internal defect, caused by wear and tear, that we successfully remedied in our workshop in The Netherlands in 2020.

Cooling Water System Reverse Engineering

After 25 years of intermittent operation and of being exposed to the elements, the cooling water radiators of an 3500 kW emergency diesel generator installed in a thermal power plant in Macau had degraded considerably. Thus, the power plant owner decided to replace them.
Unfortunately, the original documentation and specification were not available anymore. Therefore, QuantiServ reverse engineered them and got 12 new elements made by a specialized manufacturer.
The new radiators have just been installed and commissioned and will provide reliable cooling for many years to come.
Although this was a small case, it illustrates the important advantages that reverse engineering provides. Many of the industrial plants that we maintain and repair on behalf of our customers have a lifetime of many decades. But that does not mean that the documentation always survives that long, or that spare parts are still available. And sometimes even the OEM himself, or his sub-supplier, may not exist anymore.
It is thus comforting to know that QuantiServ has the skills, tools and experience to reverse engineer and reproduce all kinds of machinery components, even very complex ones and entire systems.

Cleaning of a Heavily Contaminated MV Alternator in Nigeria

Our alternator specialists have just completed the in-situ cleaning of a severely contaminated medium-voltage alternator in a power plant in Nigeria, Africa.

The alternator has been in operation for around 32,000 hours in a very dusty environment without ever having been cleaned. Eventually, the winding temperatures reached unacceptable levels so that the unit’s load had to be reduced. A visual inspection by the plant’s operator and insulation testing by a specialized company revealed that the windings were very dirty and that the insulation values were too low. The Polarization Index (PI), which was calculated to be 1.4, was unacceptably low. The manufacturer of the alternator, Leroy Somer, specifies the PI to be at least 2.0 while we recommend not less than 3.0.

The specification of the alternator is as follows:

Manufacturer: Leroy Somer Type: AC Alternator
Nominal Power: 7600 kVA Nominal Voltage: 11000 V
Nominal Speed: 750 rpm Frequency: 50 Hz

Condition of the alternator before cleaning:

Condition of the alternator after cleaning:

5000 Volt Megger readings before and after cleaning:

QuantiServ’s technicians achieved a superb result without using any harmful chemicals or CO2 at all. Only water and a special formula of water-soluble, non-toxic detergent was used.

The power plant operator was highly pleased with the result of our cleaning work. He was told by more than one party that the rotor had to be withdrawn from the stator for cleaning. That we did it in-situ saved him a lot of time and money.

This case shows well the outstanding effectiveness of QuantiServ’s alternator cleaning method. So far we have not yet come across an alternator that we could not clean in-situ and where dismantling was required!

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In-situ machining of lateral surfaces on 20V32 engine block in Bangladesh

Lateral surfaces before and after in-situ machining

Lateral surfaces before and after in-situ machining

In-situ machining of lateral surfaces on a 20V32 engine block in a power plant in Bangladesh

In October 2016, QuantiServ received an urgent request to carry out in-situ machining on a 20-cylinder 32-bore engine block in a power plant in Bangladesh. During the replacement of the crankshaft it was noticed that both lateral surfaces of main bearing cap number 5 showed signs of severe fretting and were in need of machining.

Immediately, in-situ machining equipment was prepared at QuantiServ’s Dubai workshop and was sent to site. Once the equipment had arrived at site, QuantiServ’s engineers from Dubai performed in-situ machining on the engine block to achieve a clean surface that was free from damage. The in-situ machining process was constantly monitored by laser to ensure perfect alignment and adherence to very tight machining tolerances.

The main bearing cap was sent to a local workshop in Bangladesh for machining and installation of compensation plates. This process was supervised by QuantiServ’s engineers. Once the machining was completed, all mating surfaces for the main bearing cap were checked with marker blue to ensure a perfect fit.

Once the work was completed, a final check by laser on the assembled bearing cap showed that both the bore alignment and diameter fully conformed to the engine maker’s specification.