From short block to genset: Which general overhaul option is right for your data center?
Every asset manager in the data center knows this moment. The maintenance schedule signals the approaching end of the lifecycle for one of the large gas engines.
After approximately 60,000 operating hours, routine maintenance is no longer sufficient. The machine requires a major overhaul to ensure reliability for the next decade. However, the way to achieve this is not set in stone.
The strategic question is how extensive the intervention should be. Should only the core component be replaced, or would a complete replacement be more sensible? The decision depends on many factors.
This includes the available budget, the condition of the auxiliary equipment, and the maximum tolerable downtime. In an environment where every minute of downtime represents a risk, choosing the right overhaul method is critical to economic success.
We analyze the three common options and help you decide.
1. The Basic Option: Gas-Engine Short-Block Service
The so-called short block is the engine’s core component. It includes the crankcase with the crankshaft, the camshaft, the pistons, and the connecting rods. All of these components are preassembled and together form the short block.
For many operators, the gas engine short block service is the most economical option. In this process, the old engine block is removed and replaced with a refurbished unit. Existing auxiliary components—such as cylinder heads, turbochargers, oil coolers, and pumps—are carried over from the old engine if they are still in good condition or have been overhauled separately.
Advantages and disadvantages of a short-block exchange
This method is particularly notable for its cost efficiency and resource conservation, but it also presents challenges:
- Low investment: You only pay for the motor core and can continue using existing, functioning peripherals, keeping the investment low.
- Simple logistics: A short block is significantly more compact and lighter than a complete genset. This greatly simplifies transport within existing buildings, since it often fits through standard industrial doors.
- Assembly effort: Because many components, such as oil pans and radiators, need to be modified, the on-site labor time increases significantly.
- Risk: Modifying equipment under time pressure in the machine room carries a higher risk of assembly errors than performing the work in a clean workshop.
Target audience: This option is particularly suitable for operators with a limited budget whose peripheral devices, such as turbochargers or mixture coolers, still have a long remaining service life or were recently replaced.
2. The Golden Mean: The Long Block
If you want greater safety and to further reduce on-site assembly time, you can often opt for the Long-Block. This variant builds on the Short-Block but already includes other essential components.
A long block is typically supplied fully assembled with the cylinder heads and valve train installed, and often with new oil pumps and coolers. The main advantage is that it is prefabricated under clean-room conditions at the factory.
Since the critical assembly of the cylinder heads and the precise adjustment of the valve train are already carried out by specialists before delivery, the risk of errors on the construction site is significantly reduced.
Why the long block often comes out on top
Although the Long-Block costs more to buy than the Short-Block, it reduces costly on-site technician hours and offers additional benefits:
- Time savings: Downtime is significantly reduced because the unit requires less complex conversion work and the motor can be restarted more quickly.
- Safety: The critical components are already assembled and tested, reducing the error rate during commissioning.
- Warranty: You receive a warranty covering the entire powerhead, minimizing disputes in the event of subsequent defects.
Target audience: Operators who prioritize safety and speed but want to avoid the extremely high costs and logistical challenges of a complete genset swap.
3. The most comprehensive solution: replacing the genset
In some scenarios, looking at the engine alone isn’t enough. A genset consists of the gas engine, the generator, and the common frame. If the generator also shows signs of wear, or the frame is weakened by corrosion, replacing the entire genset may be the most sensible option.
The entire unit is lifted out of the engine room and replaced with a brand-new or fully refurbished unit.
This is often the fastest method in terms of actual on-site labor time, since it is a plug-and-play solution. In addition, you will receive a system that meets the latest technical standards, with the motor and generator perfectly matched.
Logistical challenge
However, the logistical challenges are enormous and often underestimated:
- Structural measures: Installing a genset weighing several tons in existing buildings often requires opening roofs or demolishing walls.
- Costs: The investment costs (CAPEX) are the highest for this variant.
- Lead time: Planning such heavy-load deliveries and crane operations requires a lot of time.
Target group: Operators of very old installations whose generator or frame is also worn out, or who plan to repower to a higher power class.
Decision support: Which factors tip the balance
Choosing the right option is always a decision made on a case-by-case basis. You should take the following criteria into account in your assessment.
Peripheral status
A professional assessment is the first step in any planning. Are the turbochargers, mixture coolers, and cylinder heads still in good condition? Then there’s a strong case for the gas engine short-block service, since you don’t need to dispose of functioning parts unnecessarily.
However, if these parts are also at the end of their service life or show wear, it’s often worth opting for a Long-Block. Operating a new short block with an old, inefficient turbocharger doesn’t make economic sense and can lead to further damage.
Time window for downtime
How long can the system be offline? A genset exchange is often the quickest option, but it requires extremely long lead times for logistics planning and procuring the unit.
A short-block exchange carried out entirely on-site takes longer, often 3 to 5 days, but is logistically more flexible and often available sooner, since suppliers like PowerUP frequently keep short blocks in stock. Here, a trade-off must be made between the delivery time (lead time) and the assembly time (downtime).
Budget and TCO
The short block has the lowest capital expenditure (CAPEX) and helps preserve the annual budget. However, one must factor in the risk that older attached components may fail later, which would increase operating costs (OPEX) and downtime in subsequent years.
The long block often offers the best compromise between protecting your investment and minimizing risk, as the most critical components have been renewed and guarantee a long service life.
Tailor-made solutions for your fleet – from PowerUP
We understand that every data center is different. That’s why we do not offer a standard answer, but a solution tailored to your situation. We offer flexible options for a complete overhaul.
Whether you opt for an efficient gas-engine short-block service or prefer a comprehensive long-block solution, we deliver quality. Our components are suitable for use in Jenbacher®, MWM®, Caterpillar® or MTU®, as well as other makes, and are optimised for durability. They were developed by PowerUP as stand-alone alternatives and are not original parts of the engine manufacturers mentioned.
We are happy to advise you on-site, assess the condition of your system, and work with you to develop the optimal roadmap for the overhaul. Technology is our driving force; efficiency is our focus.
