Early model year Power Strokes have a different type of injection system than most modern-era light duty diesels have. If you’re a regular reader, you’ve heard me talk about HEUI (Hydraulically actuated Electronically controlled Unit Injection) systems before. HEUI systems, like those found on 6.0L and 7.3L Power Strokes, use high-pressure oil and an electronically controlled mechanical injector to inject fuel at an even higher pressure into the combustion chamber or bowl. Simply put, within the injector, high-pressure oil pushes on a large piston, which then pushes on a smaller piston, pressurizing the fuel and spraying it into the cylinder for combustion. The system has multiple parts, but for the purpose of this article, we’ll focus on the oil side.
On a 6.0L or a 7.3L Power Stroke, oil is taken from the pan via a low pressure oil pump (aka LPOP) where it’s distributed to the turbo, HPOP (High Pressure Oil Pump), oil cooler, and to various galleries that feed the bearings, piston cooling nozzles, etc. The HPOP then takes the oil and pressurizes it, sending between 500 to 3,000 psi of oil to the injectors, depending on engine load. This oil pressure is then sent to the injectors, where it’s used to increase fuel pressure (at the injector tip) up to 21,000 psi for the combustion event. For our 500-rwhp 7.3L project, having a more than adequate supply of oil was extremely high on our list, as it should be for any HEUI engine owner. Outside the fact that larger injectors use more oil than stock (and therefore need more to perform correctly) we wanted to make sure the entire oil system would provide us with all the oil we’d ever need, whether it’s for injection purposes or engine lubrication. To get this extra oil supply, we needed to upgrade to a larger HPOP for the injectors, and we also decided to upgrade our LPOP for a higher flowing version to supply the HPOP and the rest of the engine.
For the new and improved oil pumps, we called upon the HEUI experts at DieselSite. For the injection side of things, DieselSite’s Adrenaline HPOP was chosen. The Adrenaline is a completely rebuilt factory original part that’s been modified to produce a higher volume of oil (which will help larger injectors run correctly, but stock injectors will also benefit from the increased oil volume). It’ll handle substantially higher pressure oil (necessary if the engine is running a hot tune) inside it’s built using bearings instead of bushings as well as many other modifications which were done to increase durability; plus, it ties the two heads’ oil galleries together which allows for a more even oil pressure supply to the injectors. This in turn allows for a better running engine overall. The Adrenaline is a 100% bolt-on replacement for the factory HPOP. No other modifications are necessary to install it.
To supply the HPOP and other oil systems, we chose to upgrade our LPOP as well. DieselSite’s High Volume LPOP does exactly what the name implies: It flows more oil at a slightly higher pressure. While this modification is not necessary for stock injectors, or even for the 238/80 units we’ll be installing soon, it just makes sense. More oil for every system (lubrication, cooling, and injection) can never be a bad thing.
Installation, while daunting, was fairly simple and straightforward. The only specialty tool we needed when swapping the parts (in the driveway) was a harmonic balancer puller. Other than that, the whole job was done in one lazy Saturday using simple hand tools. DW
Once both parts were installed, we changed the oil to prevent any damage from contaminated oil using Amsoil’s 15W-40 Premium Synthetic Diesel Oil. We also topped off the HPOP reservoir to make sure the HPOP had a good supply of oil to draw from right off the bat. Before starting the engine, we pulled the IDM fuse (essentially shutting all the injectors off) and cranked the engine over without starting it for three 30-second long sessions with a cooling-off period between each session. We did this to ensure as much oil as possible made its way through the HPOP and injectors to prevent damage upon startup from oil starvation. With the IDM fuse back in, we turned the key over and the 7.3L started quicker than it ever had before. We also noticed the idle was much smoother, and it just sounded like it was running healthier. We took it out for a test drive and the difference was obvious. Due to the stock injectors, the difference wasn’t huge, but the truck did have a noticeable increase in torque and responded to throttle input better than before. We also noticed we were seeing 10-20 psi more of oil pressure. So far, we’re very impressed with DieselSite’s Adrenaline HPOP and High Volume LPOP.