A dead engine doesn’t mean you have to replace the entire machine. Nathan Kitchen, Sales Manager, Engines at DiPerk Power Solutions, explains why hirers should consider a rebuild before committing to Stage V replacement.
When a machine comes back from site with an engine at the end of its life, too often the default answer has been to scrap it and buy a new version.
But for machines powered by Stage IIIA engines, it doesn’t necessarily mean the entire machine needs to be thrown out. In many cases the wider machine still has plenty of potential left and a remanufactured engine can keep it working for far less than the cost of an entirely new machine.
Emissions standards for non-road mobile machinery (NRMM) have been tightened in stages. Stage IIIA cut the amount of particulate matter engines could emit, but it did so through improvements to the engine itself. Unlike later stages, it didn’t require extra exhaust-cleaning equipment such as a diesel particulate filter (DPF) or a selective catalytic reduction (SCR) system, which runs on AdBlue.
Any new machines placed on the market since 2019/20 have had to meet Stage V regulations such as tighter limits on carbon monoxide, hydrocarbons, NOx and particulate mass. But those updated requirements only relate to new equipment. Stage IIIA machines can still be hired out, repaired and rebuilt in the UK.
If you scrap a Stage IIIA machine and replace it with a new one, the new replacement machine must have a Stage V engine. However, if you were to rebuild the engine, or fit a Stage IIIA service replacement engine (SRE), which carries its own emissions compliance label, then the entire machine stays under Stage IIIA regulations.
There is no national date for phasing out Stage IIIA, though many expect it to be around 2035. Even with that in mind, a well-maintained machine could have up to nine more years of hire ahead of it. Some areas are moving faster, however. London’s Non-Road Mobile Machinery Low Emission Zone requires Stage V across the capital from 2030, so it pays to know where each machine in your hiring portfolio is likely to work.
The biggest issue facing Stage V machines is low loading and this particularly impacts hiring of equipment.
If a customer has booked a 20 kVA mobile generator, but the depot only has a 40 kVA available, then that’s what they receive. The physical reality is that on site all that mobile generator may need to power is a grinder and a drill. The problem is, when a generator runs at just 5 to 8 per cent of its capacity, like a 40 kVA unit powering a grinder and a drill, the exhaust never gets hot enough. Soot keeps building up and doesn’t burn off, so then the diesel particulate filter (DPF) blocks. As a result, the machine loses power or shuts down and needs a technician to clear the filter or replace it.
Stage IIIA engines aren’t designed for low loading either, but with no DPF to block, they are far more forgiving of how hire equipment actually gets used on site.
The additional exhaust equipment that Stage V requires makes the engine more expensive overall. Comparing engines of the same output, a Stage V generator engine costs on average around 35% more than its Stage IIIA equivalent; for industrial engines, the premium is around 40%.
Then there’s the cost when things go wrong. If a DPF blocks and can’t be recovered, the bill can reach around £8,000 once a technician has been sent out, on an engine that may have cost £12,000 in the first place.
Rebuilding Stage V is also more involved. To stay compliant, a rebuilt Stage V engine needs to effectively go back out as new, with a new particulate filter and other aftertreatment parts.
Now scale that up. A large hirer with 250 Stage IIIA machines faces a very different bill if it replaces them all with Stage V than if it rebuilds the Stage IIIA machines worth keeping.
While Stage V results in lower emissions at the point of use, that isn’t the whole story. Whether point-of-use lower emissions outweigh the environmental cost of destroying one serviceable machine and building another is a fair question. Scrap a machine because its engine has failed and the chassis, hydraulics and cab go with it. Stage V catalysts and DPFs also rely on platinum-group metals that must be mined and refined, with the associated environmental impact that comes with that process.
As well as this, older equipment has traditionally found a second life in emerging markets. Stage V machines are far less suited to those markets because their exhaust equipment needs high-quality, low-sulphur diesel that isn’t always available in those locations. Instead of being reused, there is a danger more machines are going to end up being scrapped.
Switching fuel can cut emissions further when it comes to older equipment. For example, all Perkins engines can run on HVO (hydrotreated vegetable oil), a renewable alternative to diesel that can be used without modifying the engine. That gives Stage IIIA fleets another way to reduce their carbon footprint.
A rebuild isn’t right for every machine. Before deciding, fleet managers should look at three things:
- Condition of the wider machine: The engine is only one part of the machine. If the rest of it is tired, the hydraulics, the transmission, the bodywork, then a rebuilt engine isn’t going to make it worth keeping.
- Remaining earning potential: Look at its history, demand for that class of equipment and how many years of hire it can realistically deliver before it will likely be forced out of use by regulations.
- Repair costs: Compare the cost of a rebuild or a replacement engine with the cost of a new Stage V machine.
Rebuilding the engine won’t always be the right call for a Stage IIIA machine. But for fleets running Stage IIIA equipment, it should be considered rather than making the assumption that the whole machine automatically needs replacing. A dead engine doesn’t have to mean a dead machine and keeping a legal, earning asset working may be the soundest decision, both commercially and environmentally.
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