Why your first Ford 7.3L Powerstroke didn’t last, and your next one may not either!
It’s highly likely if you have a 7.3L and are looking for answers to some of your issues you may be searching words like “white smoke” or “low compression”. These are not uncommon issues to the 7.3L And you may see that white smoke appears a lot worse if you live in cooler climates. Many guys replace their glow plugs in hope of getting rid of this rough idle, and white smoke in the mornings. But unfortunately, low compression can’t be resolved with glow plug replacement.
The auto-ignition temperature of diesel is 430 degrees fahrenheite, so having the cylinders warmed by the glow plugs are necessary. On many engines though, the glow plugs won’t even cycle until the temps drop below 59 degrees. So if you’re chasing rough idle and white smoke on your 7.3L during temps above that, by replacing glow plugs, you’re chasing your tail. It is important to note, that sticking spool valves in injectors can also cause rough idle and even white smoke if there is poor atomization because of it.
The Ford 7.3L Powerstroke platform has been a solid one for the F-series truck owners. Interestingly enough, the International/Navistar engine that was sold to Ford for their trucks, was a collaboration between International and Caterpillar. Caterpillar designed the “HEUI” injection system. Or a hydraulically actuated, electronically controlled, unit injector. The engine is known as the T444E in the International sector. This is because it is direct injected, turbocharged with 444 cubic inches of displacement and electronic, unlike its predecessor, the IDI 7.3. Which was indirect injected.
Ford, failures, and frustrations…………
The failures of the 7.3L Ford Powerstroke engine in the 99-03 are exclusive to Ford. You typically won’t see this failure in an International Truck. There is a good reason as to why. That’s because the airbox of the 7.3L Ford Powerstroke F-Series Truck uses an inferior box that doesn’t seal properly. Once more, it only seals worse when an aftermarket air filter is added. This in turn has led to many Ford 7.3L Powerstroke Engines being replaced because of low compression. Dirt is allowed to escape past the filter and into the engine, where it is trapped between the rings and cylinder wall. This will damage both the rings, and the wall and allow what is known as “blow by.” This condition is where the compression gasses pass the rings, and enter the crankcase. This causes the vapors to be pushed out of the oil filler neck you often see in videos.
Once this has taken place the only recourse is to pull the engine, and then send it out to be machined. The cylinders would have to be taken to the next appropriate size piston that would allow them to clean up the damage. It’s the little things that make big differences. Rarely will you ever hear me advocate for an aftermarket filter. But in the case of the 7.3L, I don’t know that there is a more cost effective return on investment than this. A simple matter like replacing the stock filter, literally will save you the cost of an engine.
But you may be asking yourself, I thought he just said they seal worse. Well, yes I did. By ditching the box altogether, and replacing the entire airbox, you are able to seal up the areas that are notorius for leaking. There is no help for the factory box, and any attempt to add a filter to it typically makes it worse.
Why OBS 7.3L Powerstrokes outlast the Super Duty Powerstroke.
That being said, you will often notice that the 94.5-97 engines “last longer” and it has nothing to do with the engine. It does however, have everything to do with the filtration system.
This dirt also is what causes so many issues with the valve guides wearing prematurely. And dirt getting between the valve and seat exacerbates the wear of the valve face and wears the valve margin razor thin! (See Photo Below)
Most of the engine builders will reuse valves. Grinding them, creating a new surface for the valve face to seal against the seat. The issue however, is that by grinding a valve past its margin, means there is less material for heat dissipation. Eighty percent of the heat absorbed into the valve is dissipated through the seat. That means it is absolutely critical that there is enough material for the valve to endure the heat cycle. If there isn’t the valve will crack, this in turn, at best causes low compression. At worst, will break off and drop into the cylinder. The rest is history. The engine at that point is done, and must be overhauled. So you can see just how simple one dimension can drastically change the longevity and performance of the engine. There are good reasons why we at Choate Engineering Performance build engines a certain way. Any Choate Engineering Performance Engine you buy, is engineered to outlast the competition. The approach to each platform is very specific! We start at what we call the CIA. That is the best source of information. That acronynm means, concern, inspect, analyze. Our engineering starts with the failure and works backwards. This means, starting in disassembly aka “teardown.” Just like the valve failure, it’s not enough to simply look at the failure and see the effect. The cause is the greatest concern, because that is the first step to resolution.
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7.3L Powerstroke Workhorse Plus Cylinder Head Reman
$1,550.00 – $1,750.00 Select options This product has multiple variants. The options may be chosen on the product page -
7.3L Short Block Model C Engine 1994-2003
$5,500.00 – $7,000.00 Select options This product has multiple variants. The options may be chosen on the product page -
7.3 Powerstroke DUALOY Piston Kit 1994-2003
$630.00 Select options This product has multiple variants. The options may be chosen on the product page -
Cylinder Head Porting
$1,000.00 Add to cart -
7.3 Long Block Daily Driver Engine Ford Powerstroke – 1994-2003
$10,000.00 – $11,500.00 Select options This product has multiple variants. The options may be chosen on the product page -
7.3L Billet Freeze Plug Kit – 1994-2003 Ford Powerstroke
$299.00 Add to cart
“HEUI”…..Helping Engines against Uneducated Installers…..
The 7.3L powerstroke engine doesn’t suffer from many problems. Because it is the HEUI system, it saves itself. The real acronym for HEUI is “helping engines against uneducated installers.” While that is a bit tongue and cheek, there is a lot of truth to it. The fact that the engine needs high pressure oil to fire the injectors means that it cannot run without oil. I have literally seen guys have enoromous oil leaks and run the truck until it gets so low on oil it can’t fire the injectors. Then, coast to the side of the road, pour more oil in and keep going. We had a customer refuse to pay a tow bill, and against the caution of us, decided it much better to just drive it. But the time he got to our shop he had lost 2.5 gallons of oil. Not a great idea, certainly it causes wear to the low pressure oil pump as well as other components. But, it won’t typically lock up an engine as a high pressure common rail would do.
The true fix is to fix the cause, (the faulty air filter) and fix the effects. Which is the worn valve guides, and valves. There are some major upgrades we are able to do with the material in the valves we use now, verse the OE.
All things aren’t equal….
There is something we else that needs to be considered when purchasing a Remanufactured 7.3L Powerstroke engine. And that is, only a small few remanufacturers will actually replace the factory seat. The original seat is integrated into the cylinder head. It is induction hardened to insure that the seat will not wear causing the valve to sink farther and decrease the lash. Most will “cut new seats” and install the valves. That isn’t ideal. You are cutting away the hardness of the seat, as the induction hardening process only penetrates the material so much. Along with that, the induction process can encourage cracks over numerous heat cycles. The crack has the potential to continue to run until it typically meets a hole. Most often a glow plug, or injector, possibly another valve. This isn’t the best choice for fixing the cylinder heads. You expect at the very least, no less than your factory OE Ford 7.3 Powerstroke Engine gave you. But by reducing this hardness, you are getting less than what you had before. That is why Choate installs a hardened 4Nseat that can withstand temperatures up to 1600 degrees. This has better wear characteristics than that of the parent material.
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Ford 7.3L Powerstroke Diesel Front Cover
$298.90 Add to cart -
KC Drop In Billet Wheel – 7.3 POWERSTROKE (L99-03)
$190.00 Add to cart -
NEW GEN 2 KC300x Stage 2 Turbo (63/73) – 7.3 POWERSTROKE (94 – 98)
$1,240.00 – $1,540.00 Select options This product has multiple variants. The options may be chosen on the product page -
7.3L Powerstroke First Oil Change Kit
$130.00 Add to cart -
7.3 Ford OEM Water Pump 96-03
$302.20 Add to cart -
7.3L Powerstroke Engine Cylinder Head Bolt Set
$87.00 Add to cart
“Keeping things straight”
Keeping it straight is as critical if not more than all the other items. We mentioned the failures of the guide wear. The guide is a crucial portion of the valvetrain. It’s literally what keeps the valve straight and maintains the concentricity of the valve face to the valve seat. If there is “runout” then the valve will never close against the seat properly. This will lead to combustion gas loss, pressure drop in the cylinder, which is everything you need to force the piston back down the bore. Transferring the thermal energy into mechanical energy. The better the seal, the more of the pressure that gets excerted in the direction you need. But not only that, if there is a leak, it can act like a cutting torch over time. This intense heat that is escaping between the two surfaces will erode whichever is softest, or exceeds its structural integrity first.
Imagine taking an air hose and blowing a rubber tipped nozzle through your thumb and finger. I don’t suggest this, by the way. But if you know, well you know. Burns doesn’t it? Yeah, don’t do that anymore! But that’s a decent example of the leak that takes place between the two surfaces. Now imagine these gasses are 1300 degrees. It’s not an environment that is condusive to a long living valve and seat. That is why concentricity matters.
At any rate, the guide is cast into cylinder head. And there are better materials as well as process that will help make the engine live longer. Choate Engineering uses a iron matrix guide to accomplish this. Again, it isn’t just about the part. It’s also about the installation that makes the result worth doing. We all know that the cylinder walls are cross hatched for oil retention. Without this the rings would wear at a rapid rate, and it also wouldn’t seal properly. The guides are similar in that they can benefit from honing them once installed. This cross hatching serves the same purpose, lubricating the valve stem and providing a film of protection for the guide.
All this started out with a dirty air filter. It’s kind of surprising how the “little foxes spoil the vines”but it really can cost you a lot of unnecessary money, if you will just take care of the small things while they are small.
When it’s all said and done, the Ford/Navistar/International engine is a very forgiving and solid platform. You can get away with things you wouldn’t dream about in the modern diesel. For these reasons, it makes a lot of sense to many truck owners to keep these engines alive and going for millions of more miles. The dependability and the cost savings in repair and maintenace have no doubt earned their place in our diesel sooted souls.
I am interested in ordering a 7.3 liter powerstroke Engine. Any infromation that you can give me in regards to that would be greatly appreciated. Thank you and have a great day. Please call me at 208-407-5046.