Welcome to Top Tech Questions. Oftentimes, readers contact us with questions about articles, or to praise us on what a good job we are doing. But our favorite form of reader communication is tech questions. Our Top Tech section is a place where you ask what's on your mind, and we answer it. Got a trouble code? Wondering how to get your engine to make more power?
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Question: OK, so I just went out and bought the Banks Power Big Hoss Bundle for my '04 Ford F-350 6.0L diesel, and now that I have it, I am a bit overwhelmed and under-informed. I have some basic questions, like: Where should my EGT, oil, and water temperatures be? What really is too hot? Why is my PDA screaming at me when my dash gauges look just as they did before the upgrade? Am I really going to blow the engine?
James Peterson Saugus, California
Answer: You'd be surprised by how many diesel enthusiasts ignore basic things like coolant and oil temperatures. It is so easy to modify new diesel trucks, many people just plug in and enjoy the power and forget that those modifications strain the engine and drivetrain far more at increased power levels than at stock ones. A programmer is used to increase timing and/or fueling in the engine, which in turn spins the turbo harder and creates more boost. This is where an intake and exhaust come in, as they free up any restriction in the stock hardware caused by the newfound increase in engine airflow. Problem is, the increased power will also tax the vehicle's cooling systems, and since most diesel owners ignore those types of upgrades (which is probably why your PDA is yelling), trouble can be the result.
| One of the biggest problems with the 6.0L Ford is that the EGR cooler can overheat the coolant on a hot tune, making your engine run too hot, and also increasing oil temperatures.
Since 6.0L-powered Fords have a propensity toward blowing head gaskets, we'd say the closer you keep to stock power levels, the better. If you can't help yourself and need more power and better fuel economy (as most diesel enthusiasts do), we'd recommend installing head studs and a larger EGR cooler made by Neal Technologies ([888] 967-6653). Also, keep your eye on your oil and water temperature and never let them exceed 215 degrees. With just a Banks programmer, EGT should never get high enough to worry about while running around town, but for towing, we'd try and keep the temperature below 1,200 degrees pre-turbo while towing, and below 1,400 degrees for short bursts (just a few seconds). Transmission temperature is another one to watch, and for that, keeping it below 200 degrees is a good rule of thumb. Also, make sure your transmission is always full of fluid. Most transmission damage occurs from being low on fluid or overheating.
Question: I have an '01 Dodge Ram 2500 with the 24-valve Cummins. I have been following your Project 24-valve build and I am very interested in making similar modifications to my truck. My concern is that the motor has almost 175,000 miles on it, and I was wondering if starting to modify the power would be a good idea with the current mileage. I would like to put on a FASS fuel system, a high-flow injection pump, larger injectors, a Banks intercooler with High-Ram intake, exhaust, and a new turbo or maybe a compound setup. Would a build like this be worth my time, effort, and money, or should I be more conservative regarding the mileage?
Chad Gingrich Lewisburg, Pennsylvania
Answer: There are a lot of diesel owners who worry about their high-mileage engines when it comes to performance modifications, and really, they shouldn't. Diesels are built a lot tougher than gas engines, and they operate at about half the rpm, so 175,000 miles on a diesel might be more like 80,000 miles on a gas-powered engine. Recently, we took the head off of Project Rust Bucket, and at 212,000 miles, it still had a cross-hatch pattern in the cylinder bores. At your mileage, blowing a head gasket is basically your only concern, and that problem can be addressed with the addition of a new head gasket and some head studs. We'd especially recommend going this route if you plan on installing twin turbos. It sounds like you're on the right track. Even with a single turbo, 450 hp at the rear wheels should be well within reach with your planned modifications, and at that power level, you should be able to enjoy your truck for thousands of miles to come.
| After 212,000 miles, our cylinder bores still looked perfect on Project Rust Bucket, our '89 Cummins-powered Dodge. With Cummins engines, we'd say anything with less than 250,000 miles is still a good candidate for performance parts, without any type of engine rebuild.
Question: I own an '02 Ford F-350 with the 7.3L Power Stroke engine. While coming home from vacation in July pulling a 38-foot fifth-wheel, the engine started missing and smoking. When I lifted the hood, the dipstick was partially out and oil and smoke were blowing out of the tube. I limped the truck to a Ford dealer, which pulled one of the heads to find that I had burned a hole in the number five piston. The piston failure scored the cylinder badly, requiring a completely rebuilt engine. I run a Superchips controller on Tow Safe mode, an AFE intake, Banks compressor wheel, and 4-inch exhaust. I have a full set of gauges and never let the EGT exceed 1,200 degrees. The mechanic says I might have had an injector misfiring. For $10,000, that's not a very concrete answer. Ford customer service was also no help and it claimed there are no issues with the 7.3L.
Roger Burk
Gill, Colorado
Answer: We're sorry you had to spend so much coin on something that didn't add any performance to your truck, and we'll do our best to solve your mystery. If an injector nozzle cracks, your engine will still run, but it will dump enough fuel into the cylinder to turn your injector into a cutting torch. If you had a probe in the cylinder, you might sense this, but most pyrometer probes will just sense an overall EGT and probably won't pick up if a single cylinder is running hot. The bad injector problem is most often found in common-rail trucks that are running home-brewed biodiesel, but we've seen melted pistons in other vehicles, too-even the old, mechanically injected ones.
| Here's an example of a piston that has been burned and melted, which usually means a bad injector or super-hot EGT readings. If the piston is just cracked without the star-shaped burn pattern, then it's probably a cylinder pressure or oiling issue.
If your piston is cracked but not melted at all, it could be excess cylinder pressure. We've seen cracked 7.3L pistons on Fords that were running a bit too much nitrous or propane, along with a healthy amount of fuel. Also, 7.3L pistons aren't known to be the strongest in the world, and if you primarily use your truck to tow and it sees 1,200-degree EGT 80 to 90 percent of the time, the constant heat cycling could contribute to a cracked piston.
Our best and final guess actually comes with some help from Brad Makinen, the owner of G&J Diesel in Billings, Montana. A few years ago, he had 20 different 7.3L Power Strokes that came to his shop in need of an engine rebuild. The problem? Clogged oil squirters caused by running cheap oil filters. Since oil squirters cool the piston, no oil spray from the squirters meant that the top of the piston overheated. Then the super-hot piston would swell and badly score the cylinder walls. All of this could happen without any of your gauges showing anything out of the ordinary. Unfortunately, this is a problem that can happen to anyone. The only way to guard against it is to use OEM replacement filters, or a high-quality oil filter.
