"Power Stroke" is the label given to a series of diesel engines for trucks, produced by Ford Motor Company since 1994. The production was initially handled by Navistar International until 2010. However, starting in 2011, Ford took over the complete design and manufacturing process, evidenced by the 6.7 L Power Stroke V8.

This series of diesel engines has developed a considerable following over the years, with some models, such as the 7.3 L Power Stroke, gaining a reputation for their durability and reliability, even almost thirty years after its first introduction. However, the Power Stroke series hasn't been without its fair share of problems, leading to a significant amount of criticism as well.

What is the Power Stroke and How Does it Work?

The Power Stroke refers to a series of diesel engines manufactured jointly by Ford and Navistar. They were primarily designed for Ford's F-Series trucks and E-Series vans. These engines are mainly arranged in a V8 configuration and come with direct injection and intercooler turbocharging features. With their emphasis on heavy-duty hauling, Power Stroke engines have gained significant recognition and popularity among pick-up truck aficionados, becoming a well-known name in many households.

The Ford Power Stroke: A Brief History

The Power Stroke series of diesel engines, introduced by Ford in late 1994, actually has its roots in a partnership that began with the International Truck and Engine Corporation (ITEC) in 1982.

The first engine produced under this collaboration was a 6.9 L indirect injection (IDI) engine, delivering a noteworthy 170 horsepower and 315 pound-feet of torque for its era. This engine was eventually succeeded by the 7.3 L IDI engine.

Between 1987 and 1993, a 7.3 L IDI engine, bearing the same stroke but a larger bore than its predecessor, was in production. This engine had an upgraded block and redesigned cylinder heads but lacked a turbocharger. This engine, however, laid the foundation for the future 7.3 L Power Stroke.

In 1993, a turbocharged version of the 7.3 L engine was launched. Although it was fortified to withstand turbo boost pressures, it didn't notably increase the power or torque output. This changed the following year with the arrival of the inaugural Power Stroke.

The first Power Stroke, introduced in 1994 and in production until 2003, had an electronically controlled direct-injection system that enabled it to generate as much as 21,000 psi, despite having the same displacement as the preceding engine. The engine, built with cast-iron block and cylinder heads and forged steel connecting rods, demonstrated impressive longevity, often exceeding 300,000 miles.

The subsequent 7.3 L Power Stroke, released in 1999, featured an air-to-air intercooler and HUEI (Hydraulically Actuated Electronic Unit Injection) fuel injectors, which were essential for the upcoming generation of Power Stroke. Like its predecessor, this engine proved to be highly durable, often surpassing 250,000 miles, and maintained its production until 2003. Even today, it is considered by many as one of the finest diesel engines ever produced.

Complying with more stringent government regulations on emissions, Ford and now-renamed Navistar, collaborated on the 6.0 L Power Stroke. This newer model included several emissions controls and a variable geometry turbo, raising the power to 325 hp and 570 pound-feet of torque. However, it suffered from issues related to certain failure-prone parts, leading to a blow to the Power Stroke’s reputation for reliability, and was eventually discontinued in 2007.

In 2008, Navistar once again partnered with Ford to create the 6.4 L Power Stroke, which employed a common rail system with piezoelectric injectors and received a boost from twin compound turbochargers, producing 350 horsepower and 650 pound-feet of torque. Despite the engine's quieter operation and enhanced power, it suffered from similar problems as the previous model, including valve train and head gasket failures, and comparatively poor fuel efficiency. This engine was only in production for a few years, marking the end of the partnership between Navistar and Ford in 2010.

After parting ways with Navistar, Ford independently produced the 6.7 L Power Stroke, featuring an Instant Start feature, a new design with a water-to-air intercooler and the DualBoost variable geometry turbo, and a lighter engine block made of compacted graphite iron. This engine initially offered 390 horsepower and 735 pound-feet of torque, but improvements over the years increased this to 440 hp and 860 pound-feet of torque by 2015, and 925 pound-feet by 2017.

In 2018, Ford expanded the Power Stroke brand to include light-duty diesel applications such as the F150 with the 3.0 Power Stroke.

Despite a few hiccups along the way, the Ford Power Stroke series of engines maintains a strong reputation.

7.3 L Power Stroke Engine 1994-1997

The Power Stroke engine was introduced in 1994, drawing from the knowledge and insights gained during the IDI (Indirect Injection) era. This entirely new engine was a turbocharged, direct-injection diesel. It employed Hydraulic Electric Unit Injectors (HEUI) and utilized a High-Pressure Oil Pump (HPOP) to generate the necessary pressure for fuel injection.

Performance Upgrades:

Exchange Turbo DI TP38 Pick-up w/o Pedestal Ford 7.3L Power Stroke 1994-1998.5 - 468485-9004-B (bddiesel.com)
Injector - DI Code AB (1825125C1) Ford 7.3L Power Stroke 1996-1998.5 - UP7000-PP (bddiesel.com)
Injector - DI Code AA (1821836C2) Ford 7.3L Power Stroke 1994-1997 - UP6999-PP (bddiesel.com)

7.3 L Power Stroke Engine 1999-2003

The introduction of the Super Duty brought a series of enhancements to the Power Stroke engine. These upgrades encompassed a revised turbine housing and the inclusion of a wastegate midway through the production year. The 1999 model continued the use of the HUEI fuel injection system, but with upgraded 140 cc injectors—a significant increase from the 120 cc ones used in the previous model. To support these larger injectors, the High-Pressure Oil Pump (HPOP) was also improved by adopting a 17° swash plate angle.

In 1999, Ford incorporated an intercooler into the Power Stroke design, leading to a boost in power output and a reduction in both intake temperature and Exhaust Gas Temperatures (EGTs).

In 2002, the engine's forged connecting rods were replaced by powdered metal rods. While these proved sufficient for unmodified engines, they could potentially become a weak point in engines that were modified to exceed 450 horsepower.

The robustness of the engine, coupled with a bolder body style and a sturdier chassis, has made this generation of Power Strokes a highly desirable choice among Ford truck enthusiasts.

Performance Upgrades:

Turbo Thruster II Kit Ford 7.3L Power Stroke (Pick-up only/No E-Series) 1999.5-2003 - 1047511 (bddiesel.com)
Injector, Stock - DI Code AE #8-Cylinder (1833640C1) Ford 7.3L Power Stroke 1999.5-2003 - UP7003-PP (bddiesel.com)
Injector, Stock -DI Code AD Cylinders 1-7 (1831489C1) Ford 7.3L Power Stroke 1999.5-2003 - UP7002-PP (bddiesel.com)

6.0 L Power Stroke Engine 2003-2007

To adhere to more stringent governmental regulations, Ford and Navistar once again collaborated to engineer the 6.0L Power Stroke. By the second quarter of 2003, this new engine started replacing the 7.3L model. It was used in Ford Super Duty Trucks until 2007 and Econoline vans until 2009. With a bore and stroke measuring 3.74 in x 4.13 in, and a displacement of 5,954 cc, it employed a variable-geometry turbocharger and intercooler, delivering 325 hp and 570 pound-feet of torque.

However, these engines faced several issues related to the failure of certain components. One such problem was the oil cooler plugging up due to sediment accumulation, a byproduct of sand left in the block during manufacturing. This sedimentation resulted in elevated temperatures and eventual engine failure. Additionally, the sediment would impede coolant flow through the EGR cooler, leading to premature failure due to thermal expansion fatigue in the heat exchanger core.

Early models from 2003 and 2004 also suffered from premature High-Pressure Oil Pump (HPOP) failure, as the initial HPOP gears proved to be too fragile and developed stress cracks in the teeth. This would cause the engine to fail to start. Moreover, Injection Control Pressure (ICP) sensor failure was another issue, prompting Ford to relocate the ICP sensor in a new HPOP design.

Further issues included high-pressure oil leaks due to low-quality O-rings, breakages in the prongs of the Snap-to-Connect (STC) fitting, head gasket failures, issues with the Injection Pressure Regulator screen, and Fuel Injection Control Module (FICM) failures.

Despite this extensive list of challenges, the 6.0L Power Stroke has garnered a dedicated following.

Performance Upgrades:

Exhaust Manifold Set Ford Power Stroke 2003-2007 - 1041480 (bddiesel.com)
Up-Pipes Kit w/EGR Connector Ford 6.0L Power Stroke 2004.5-2007 - 1043918 (bddiesel.com)
Stock Fuel Injector Ford 6.0L Power Stroke 2004-2007 (after 09/21/2003) - AP60901 (bddiesel.com)
Stock Fuel Injector Ford 6.0L Power Stroke 2003-2004 (up to 09/21/2003) - AP60900 (bddiesel.com)
Screamer Stage 1 Performance GT37 Turbo Ford 6.0L Power Stroke 2003-2007 - 1045820 (bddiesel.com)

6.4L Power Stroke Engine 2008-2010

The 6.4L Power Stroke engine was introduced by Ford as a temporary solution while they strived to comply with stricter emission standards, before the release of the 6.7L Power Stroke. Building on their partnership with Navistar, the 6.4L was essentially a refined version of the 6.0L model. It maintained the V8, intercooled turbocharged layout, but featured improvements such as compound turbos, common rail fuel injection, and a new exhaust after-treatment system for emissions control.

Regrettably, the progression made with this model led to other problems. The new after-treatment system created reliability issues that resulted in expensive repairs for vehicle owners. Other common issues included head gasket failures, valve train failures, and cracked pistons. Fortunately, this model was only in production for three years, clearing the path for a comprehensive update in 2011.

Performance Upgrades:

UP-PIPES KIT W/EGR CONNECTOR FORD F250/F350/F450/F550 SUPERDUTY 6.4L POWER STROKE 2008-2010 - 1043909 (bddiesel.com)
Exhaust Manifold Kit Ford 6.4L Power Stroke 2008-2010 - 1041482 (bddiesel.com)
6.4L PowerStroke Screamer V2S Twin Turbo Kit Ford 2008-2010 (bddiesel.com)

6.7L Power Stroke Engine  2011-2014

This engine employs eight-hole piezo injectors that facilitate up to five injection events per cylinder in each cycle. It also accommodates fuel options consisting of up to 20% biodiesel and 80% petroleum diesel. Alongside this novel fueling system, the Power Strokes from 2011 to 2014 feature a dual compressor wheel VGT (Variable Geometry Turbo) turbocharger. However, due to its unreliability, this turbo was discontinued in 2015 and replaced with a conventional VGT turbo. Another distinct feature of the 6.7L Power Stroke is its liquid-to-air intercooling system, which replaced the traditional air-to-air system seen in previous models.

Emission controls include exhaust gas recirculation, Bosch's Denoxtronic-based selective catalytic reduction (SCR), and a diesel particulate filter (DPF).

Initially, the engine output stood at 390 hp with 735 pound-feet of torque. However, shortly after production began, Ford announced that they had updated the engine. Even though no modifications were made to the engine hardware, enhancements to the engine control software led to a power increase, with the engine now capable of reaching 400 hp at 2,800 rpm and 800 pound-feet of torque at 1,600 rpm. Interestingly, despite the power increase, fuel economy was also improved.

By 2015, the engine ratings had risen to 440 hp and 860 pound-feet of torque. According to Ford, this power increase was the result of a new turbocharger, new injector nozzles, and improvements in the exhaust system.

Performance Upgrades:

Exhaust Manifold Kit - Ford 6.7L Power Stroke F250 / F350 Pick-up 2011-2014 & F350 / F450 / F550 Cab & Chassis 2011-2016 - 1043007 (bddiesel.com)
Screamer Stage 1 Retrofit Turbo Kit Ford 6.7L Power Stroke F250/350 2011-14 & F450/550 2011-16 - 1045824 (bddiesel.com)

6.7 L Power Stroke Engine 2017 +

By 2017, the 6.7L Power Stroke engine saw no major changes except for modifications in packaging and turbocharger updates. Thanks to these tweaks, the engine's torque increased to 925 pound-feet at 1,800 rpm, even though the horsepower remained constant. However, in 2018, Ford enhanced the output to 450 hp and 935 pound-feet of torque, competing with the Duramax and Cummins engines manufactured by GM and Ram. By 2020, the Power Stroke's output escalated to 475 hp at 2,600 rpm and 1050 pound-feet of torque at 1,600 rpm, which positioned it as the industry leader in both torque and horsepower.

With its longstanding reputation for resilience and high performance, Ford's Power Stroke engine series keeps attracting new customers while still delighting long-time fans whose vehicles have proven their longevity over the years.

Performance Upgrades:

Exhaust Manifold Kit - Ford 6.7L Power Stroke F250 / F350 Pick-Up 2015-2019 & F350 / F450 / F550 Cab & Chassis 2017-2019 - 1043008 (bddiesel.com)
Screamer Turbo Ford 6.7L Power Stroke F250 / F350 / F450 / F550 Pick-up & Cab-Chassis 2017-2019 - 1045827 (bddiesel.com)