This is Part Two of a three-part story. Click here to read Part One, and here to read Part Three.
When performing an overhaul, a technician must disassemble the engine and inspect vital components to determine what needs replacing. Then they’ll put it all back together again. A successful overhaul hinges on a technician having the right skills and training along with the right tools and parts.
With respect to the parts, both OEs and aftermarket companies offer overhaul kits to make it easy for the technician to get their hands on the key items that need to be replaced. For example, on the OE side, the Mack Trucks Re-Power program offers several options for fleets looking to “refresh” an engine, including an engine overhaul. Mack offers an in-frame overhaul kit using genuine new parts as well as a remanufactured overhaul kit.
“We load our REMACK (remanufactured) overhaul kit with a remanufactured connecting rod, and we’ll preload a cylinder kit so it’s easier to install,” said Sherman Williams, director of remanufacturing and parts product development at Mack Trucks. “The customer has the choice of having a Mack dealer handle the installation or buying the kit over the counter and doing it themselves. It’s not an easy task, though, which is why we tend to lean customers toward our dealers to make sure the installation is done correctly.”
In the case of Detroit, its StepUp Overhaul program has four progressive levels. Using the DD15 engine as an example, Step 1 is a basic overhaul kit that includes the following:
- Six cylinder kits, which include pistons, rings, pins and bushings, cylinder liners, and seals
- Connecting rods
- EGR actuator linkage nut
- Oil pump, oil filter, oil pan gasket
- Coolant filter
- Fuel line kit, fuel filter kit
- Lower-end bearing kit
- Cylinder head bolt set
- Cylinder head gasket kit
- Block gasket kit
Step 2, the Super Overhaul, adds a high-pressure fuel pump, cylinder head assembly, and coolant thermostat. Step 3, the Complete Overhaul, adds a turbocharger, axial power turbine and turbine gearbox, water pump, and set of six fuel injectors.
“Choosing the right package comes down to the type of wear the technician is seeing in the engine,” said Michael Young, powertrain product marketing manager at Daimler Truck North America (DTNA). “It also comes down to how much of the engine a fleet wants to overhaul based on the expectations they have for how long they expect to continue running the engine.”
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Jim Madich, engine service supervisor at Blaine Brothers, said the company typically encourages its fleet customers to opt for the highest level of overhaul kit, regardless of make or model. “If one of the components fails that you didn’t replace, it would be a real shame to wipe out an overhauled engine just for trying to save a few bucks,” Madich said, adding that it’s also important to know how the warranty might be affected by not replacing certain components.
Aftermarket overhaul kits are another option for fleets. In the case of Diesel Rebuild Kits, Paret said they ask for an engine serial number. “This allows us to determine which specific components are needed for the overhaul, which allows us to provide the fleet with a 100% match for what it needs,” he explained.
In the case of a routine in-frame overhaul—where the technician pops the head off and installs new pistons, liners, bearings, and rings—Paret said it’s a relatively quick procedure for a good technician. “More importantly, it helps bring you back to zero-hour operation of the engine,” he added. “The technician also wants to address the cylinder head to make sure it still has a flat surface. They could take it to a machine shop to make sure it’s still in spec.”
As a distributor for major U.S. aftermarket manufacturers like Interstate-McBee, IPD, PAI, FP Diesel, and AFA, Paret said Diesel Rebuild Kits incorporate components that are more affordable than genuine OE but not of lesser quality.
“The parts we use are designed to meet or exceed the OE part,” said Alejandro Paret, owner of Diesel Rebuild Kits. “And in some cases, we actually offer a better warranty.”
The Diesel Rebuild Kits’ website says most of their brands come with a two-year warranty, though some components that feature a high-performance coating are warrantied for three years. That is generally in line with what many OEs offer.
An in-frame overhaul is not a fleet’s only cost-effective option for “refreshing” an engine, however. In fact, Mack’s Williams has witnessed a trend away from in-frames. Part of that is technician-driven, meaning that many of today’s technicians don’t have the time, skills, or desire to perform a complete in-frame rebuild. The bigger factor, however, relates to reliability.
“When you move up the tiers of repower overhauls, from a basic in-frame overhaul to either a remanufactured 3/4 or 7/8 swing engine, you’re getting a much higher-quality product,” Williams said. Thus, along with its overhaul kit, Mack Trucks also offers two reman engine packages. One is a 7/8 engine, complete transmission, and carrier. The other is a basic 3/4 engine and short transmission if the fleet wants to refresh the entire powertrain.
Step 4 of Detroit’s StepUp program also happens to be a reman engine replacement.
“A remanufactured engine is factory-assembled and tested,” Williams explained. “And because it is all done at our factory, we have all the applicable updates to implement all engineering changes that have come about since the engine was first produced.”
Compared to an in-frame rebuild, reman engines typically have faster installation turnarounds.
“Our customers want to increase their vehicle’s utilization,” Williams said. “When you’re going from an in-frame overhaul to swinging an engine, you’re decreasing downtime. You’re also increasing the quality of what you’re getting. When you have a factory-remanufactured 7/8 engine that’s dyno-tested, along with up to three years of warranty coverage, there’s a lot of value there.”
For more on how to train and select technicians for an engine overhaul job, see Part Three.
