How does a 7.3 powerstroke work

We know of several 7. Had these engines been fitted with head studs a popular addition in the aftermarket, which makes the stock 7. While the generally accepted threshold for boost on a 7. Virtually nothing is exotic about the large bore, 7. Like the crankcase, the cylinder heads were cast from gray iron and feature two valves and two pushrods per cylinder. Highly forgiving, hydraulic lifters actuate the intake and exhaust valves, while eliminating the need for periodic adjustments.

A fixed geometry, journal bearing turbocharger kept the forced induction side of the 7. Instead of being equipped with a wastegate, the exhaust side was opened up courtesy of a 1. In direct comparison, the VGTs that followed would prove fairly problematic on the 6. In addition to the psi of oil pressure being used to lubricate the engine, the oil in the high-pressure circuit gets pressurized to more than 3, psi. This builds tremendous heat extremely fast. Luckily, the externally-located oil cooler on the 7.

In addition to its location exposing it to the cooling effects of outside air, its large internal passageways never plug up. In direct contrast, the oil cooler integrated into the lifter valley of the 6. The only type of failure associated with a 7. Sign up for more restomod content to add horsepower to your inbox. Complex Yet Durable Fuel Injection System Though a bit labyrinthine, the oil-activated fuel injection system used on the 7.

Ford and Navistar have had a working relationship for years, with Navistar producing engines for the Ford full-size trucks. The invention of the Power Stroke was a great move, making it the most powerful diesel on the market at the time. Everyone knew the reliability of the previous diesel models, but of course they all wanted more power. As we discussed earlier, the first 7.

With the Power Stroke, Navistar continued this block concept, but replaced the injection pump and lines with a hydraulic pump. This is commonly referred to as the high pressure oil pump HPOP. Navistar moved the injectors from their original location and placed them under the valve covers, replacing them with an electronic style that gave them a better position in the combustion chamber.

The HPOP delivers high pressure oil that is used to activate the injectors. This is where the term HEUI hydraulic electronic unit injectors comes from. In the 7. The HPOP then takes the oil received from the crankcase and pumps it back out under extremely high pressures , psi through hoses that go to top of the right and left side cylinder heads.

The barrel in the cylinder heads is serviceable and can be accessed through these plugs. However, these plugs have O-rings that can leak over a period of time. Keep in mind that the O-ring is not sold separately, it is only available as a new plug assembly. When the high-pressure oil enters the barrel of the cylinder heads there are passages that lead from the barrel to each injector. The fuel then enters a chamber in each injector.

So now the stage is set for fuel to enter the combustion chamber. We have oil that has entered the cylinder head from the HPOP surrounding the injectors in each cylinder bank.

We also have fuel that has been supplied to each injector through the fuel galley of the cylinder head via the fuel pump. Now we need to activate the injectors. For the type of head-to-block sealing seen in commercial duty applications, the 7. By comparison, its IDI predecessor featured five head bolts per cylinder and its successor the 6.

The six-bolt arrangement makes the 7. Above, a ,mile 7. At the heart of the hydraulically-activated HEUI injection system lies this component: a fixed displacement axial-piston pump called an HPOP or high-pressure oil pump. Its job is to introduce oil volume into the oil rails within the cylinder heads. Only the cam and crank are timed with each other. Physically demanding in size, there are a lot of things happening inside a 7.

When prompted by the IDM more on that below , the electronic solenoid at the top is used to pull the internal poppet valve off of its seat, effectively allowing high-pressure oil to enter the injector.

The high-pressure oil then forces the intensifier piston beneath it downward, and the nozzle needle beneath that to lift, which pressurizes the fuel present in the plunger cavity. Finally, the nozzle opens and—through a process of multiplication thanks to the intensifier piston possessing a surface area roughly seven times larger than the plunger—the 3,psi high-pressure oil figure effectively becomes 21, psi worth of fuel pressure in-cylinder.

In terms of the injection system on the 7. The MAP sensor allows the PCM to determine engine load in order to calculate the amount of fuel quantity required of the injectors. Instead of utilizing a conventional fuel supply system where the injection pump receives a steady low-pressure volume of diesel, the lift pump aboard the 7.

Later 7. Three different fixed geometry Garrett turbochargers made it onto the 7. First, a non-wastegated, T4 flange Garrett TP38 with a 1. Each version used a 60mm inducer compressor wheel, a 70mm exducer turbine wheel and a degree thrust bearing and journal bearing center section.

Despite their differences however, all turbos were oil cooled via the pedestal positioned directly on top of feed and return ports located in the block. This meant that the turbocharger required no external oil lines.