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The world of diesel performance has changed hugely over the years. That’s partly due to the impressive latent performance potential in most diesel engines. Tuners have long been bumping up stock horsepower figures on everything from work pickups to high-tech luxury trucks. While mega-horsepower diesel trucks are awesome, the further you push an engine’s internals, the more important it is to understand how tuning affects the components.

Let's take a deep dive into the evolution of diesel technology and the inherent problems that can lead to catastrophic failures, specifically in Ford’s Power Stroke engines. If you want your rig to last, understanding why things go wrong is the first step.

Why Diesel is Still Relevant

A few decades back, diesel-powered vehicles were mostly loud, smoky, and temperamental. A big-displacement gas-powered V8 was even more torquey, way smoother, and actually better for towing. But things have changed a lot since then, and modern diesels are quiet, efficient, and incredibly powerful. With technologies like variable-geometry turbos and ever-higher fuel rail pressures, efficiency and power levels continue to increase.

In fact, modern diesels offer better fuel consumption than gas engines and, of course, outlast them, too. And even though we have seen a shift in the market towards gas and hybrid vehicles, when it comes to heavy-duty trucks, diesel is still king.

And when it comes to getting the most out of a high-tech diesel engine, you need the expertise to identify weak points and resolve issues. While Choate Performance works on all types of diesel engines, in this episode, Cass focused on Ford Power Stroke motors.

Power Stroke Problems

For those who love their Power Stroke engines, you've got good reason. They’re extremely rugged and built to take a lot of punishment. But, as with almost every engine design, each generation of the Power Stroke has its own unique failure points that can result in serious engine damage if left unchecked. Fixing these factory faults results in better-than-OEM reliability and the ability to push your engine that much harder:

• The 6.0 is famous for lifting heads due to having just four bolts per cylinder, and factory head bolts that stretch under pressure over time.
• The 6.4, while powerful, often suffers from cracked pistons. The factory pistons feature a sharp ridge in the re-entrant style combustion bowl. This narrow edge has very little material beneath it and serves as a focal point for intense heat and pressure.
• The 6.7 Power Stroke was a massive leap forward, but early models (2011–2016) came with insufficiently robust connecting rods that struggled to hold up once you crossed the 600-horsepower mark. The thinner rods were designed to lower rotating mass, but couldn’t handle much more than stock power.
• Startup starvation issues can also affect several Power Stroke engines, including the 6.0, 6.7, and 7.3-liter versions. This lack of oil at the critical startup phase can cause serious engine damage if left unchecked.

But whether you own a Duramax, Power Stroke, or Cummins-powered truck, the main issue facing any diesel engine is keeping the fuel and oil separate.

The Common Enemies: Fuel Dilution and Ring Seal

When you start chasing 1,000+ foot-pounds of torque in a truck that made half that figure from the factory, you have to add a lot more fuel and air. It’s a simple equation with a dangerous side effect: fuel dilution. In the diesel world, keeping fuel out of the oil is a primary concern.

If fuel bypasses the rings, it destroys the oil film, leading directly to engine bearing failure. This can occur more readily in tuned diesel engines, as modern OEM-spec diesel engine designs are not always suited to high-performance applications unless modified to withstand the increased internal pressures.

For example, the shape of the piston bowl, whether it's re-entrant or mono-entrant, dictates how hot combustion gases move. Modern emissions standards have forced manufacturers into designs that sometimes sacrifice longevity for cleanliness. While modern engines are designed to run cleaner to meet emissions laws, those designs sometimes make the engine parts more fragile over the long haul.

The Piston Rings

Piston ring design is another factor that few tuners consider. Keystone rings are the wedge-shaped rings used in most standard diesel engines. They work fine in un-modded engines; however, as you increase piston-to-wall clearance for high performance, the vertical clearance in the land increases. This extra clearance allows the flame front to torch out the ring groove, leading to unburned diesel fuel washing the protective layer of oil off the cylinder wall.

Piston-to-wall clearance is one of the root causes of people burning out the ring groove. The flame front will actually go around the ring groove and burn that out. Choate Engineering Performance has developed proven solutions to these issues:

• Torque Plate Honing: We emulate cylinder bore distortion to ensure the best possible ring seal.
• One-Piece Rings: Utilizing advanced ring technology helps maintain a barrier between the combustion chamber and your crankcase.

Using an injector that is too small for your power goals means spraying longer and earlier, which can miss the combustion bowl and douse the rings. The bottom line is that knowing the intimate details of how a diesel engine works and understanding how each modification and upgrade affects the combustion process is key to achieving the best performance and reliability from the motor.

Don’t Compromise on Quality. Choose Choate Engineering

We pride ourselves on remanufacturing diesels to be better than OEM. The in-depth knowledge acquired from years of working on Power Stroke, Duramax, and Cummins engines has given us the expertise to get the most out of your diesel motor while enhancing its reliability. We offer:

• Short Blocks: Ideal for budget-friendly builds requiring a proven, reinforced foundation.
• Long Blocks: Fully assembled with heads, cam, and valve train for a quicker, seamless install.
• Full Running Engines: Complete drop-in solutions that are tested and ready to get to work.
• Upgraded Internals: Upgraded pistons and internal components meticulously designed to handle added horsepower and torque safely.

Choate remanufactured diesel engines are designed and machined in-house using advanced 4- and 5-axis CNC equipment, flow benches, and precision balancing technology.

Whether you are talking about cracked pistons in a Power Stroke 6.4, bearing failures in a Cummins 6.7, or broken Duramax crankshafts, we eliminate the OEM design flaws before they become a major issue. All our remanufacturing takes place in the USA, and we offer a range of engine options from mild to mental. Contact us today for help with your build, and upgrade today!