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? Send us an email at jason.sands@sorc.com and we’ll do our best to answer it.
Two Questions, One Platform
Question: I’m looking at building a first-generation Dodge as a play toy with an NV4500 transmission for strength during sled pulling, but I’d like to stay with the VE pump. I’m looking for at least 400 hp, but I’d like the truck to still be driveable to and from pulls and shows. I was thinking a 63/68/14 turbo and 7x0.014-inch injectors would be a good start—am I on the right track?
Justin Vineyard
-via email
| Kim Ponci’s ’89 Dodge has been in and out of the magazine over the past few years. In its current iteration, it sports compound turbochargers, makes 467 rwhp, and runs 12s in the quarter-mile due to its light weight.
Question (2): I have an ’89 Dodge with a Cummins and would like to make 300 hp. I know you made that a while back with Project Rust Bucket; can you tell me which parts you used?
Patrick Buzick
Ripley, Oklahoma
Answer: When you get two questions within a few hours of each other on the same subject, you know it’s time to address the issue, which is VE power. First of all, Patrick, we made 301 rwhp with Project Rust Bucket (’89 Dodge) with a K&N universal diesel air filter, Diamond Eye exhaust, Goerend converter, 60mm compressor upgrade, and Dynomite Diesel 5x0.014-inch injectors. If you’re on a budget and have a non-intercooled truck, you can probably still hit 300 with stock injectors, provided you get in a little more air (a compressor upgrade or an HX35 off a ’94 to ’98 Ram is a popular swap). Bumping up timing helps as well, although you’ll lose a little low end.
Justin, for your build, it appears as though you’re looking in the 450 to 500hp range. Although it is possible to make that amount of power on a VE with a single turbo, you’ll need to gear it for as much airflow as possible and run some fairly large injectors. Most VEs run out of steam at about 480 rwhp, provided it’s a 12mm pump. Considering the light weight of these trucks, that’s enough for most. Making this level of power on a VE requires a lot of injector, something like 5x0.018s or 6x0.016s. We don’t have any experience with seven-hole injectors, although on paper they should work well. Since the pump itself is fuel limited, you can get away with a relatively small turbo. Something like a quick-spooling 62/65/14 would work well and support 450 to 500 hp. With a small turbo, more timing can then be run, which will hurt spooling but help top end power. We’d recommend opening up the front cover and jumping a tooth on the injection pump gear (clockwise—marks should be at “C and O”) for starters, which should put you at around 20 degrees. If you want to be safely over 450, you can choose the 63/68/14 turbo for a little more air and add a little water-methanol injection, which is good for around 40 to 60 hp on its own.
Which Excursion? Question: In a recent issue, you recommended a ’00 Ford Excursion as a daily driver. I’m curious as to why you chose this model year as opposed to the ’03 or ’04 versions? The 7.3L is known to be reliable, but there’s also been some insinuation that the 6.0L engine gets a bad rap. I ultimately want something with about 400 horses and 20 mpg (if driven carefully) that can truly be driven daily and kept for years.
| Ford Excursions were available with both the 7.3L and 6.0L Power Stroke engines. Which model is right for you? Depends on whether you want to spend your money on repairs or performance upgrades.
I would appreciate your help in narrowing down between these two powerplants.
Wes Wilson
-via email
Answer: It’s clear that many diesel enthusiasts enjoy the sound and the performance of 6.0L Fords, so the fact that there’s a lot of interest in them is no surprise. With nearly all performance diesels, once power is increased, head gasket failures can become an issue. With 6.0L Fords, the difference is that it is virtually assured. Sooner or later, you will have to replace the head gasket. With a head gasket replacement and head studs, it’s also a good time to replace the 6.0L Ford’s problematic oil and EGR coolers. All said and done, the end user could be looking at a $5,000 repair bill, so keep that in mind. The upside to buying a 6.0L-powered Excursion is that 400 hp is a mere tuner, intake, and exhaust away.
With the 7.3L Ford, you’ll be spared the head gasket, oil and EGR cooler, and turbo problems of the 6.0L, but 400 hp or more isn’t as easy to make. Besides a programmer, intake, and exhaust, you’ll need to upgrade the turbocharger (Garrett’s GTP38R is a popular choice) and install some larger injectors in place of the stock versions. It’s also a good idea to upgrade the lift pump and check the health of the factory high-pressure oil pump (HPOP) in order to make sure there’s enough oil pressure to actuate the injectors. You’ll also need a converter and valvebody on the 7.3L-powered versions to handle the extra power.
If you look at it from a pure monetary standpoint, it’s probably a wash. However, once both builds are completed, the 7.3L would still have less parts and electronics to fail and may even get a couple miles per gallon better on fuel economy. If you find a screaming deal on a 6.0L-powered rig (especially one that is already broken) we wouldn’t hesitate to make the leap.
Replacing Water Pump = Blown Head Gasket?
Question: I have an ’05 Duramax with a straight pipe, AirDog lift pump, and an intake. I replaced a leaking water pump, and a week later the truck blew a head gasket. I was very careful with the install, but it seems odd that it would just be a coincidence that the head gasket would go so soon after the water pump was replaced.
Ben Bonchosky
Uniontown, Pennsylvania
| As early Duramax engines climb in mileage, expect to see more and more blown head gaskets, as many of the decades-old engines have been living their life at significant power increases over stock.
Answer: With the LLY-designation engines (found in ’05 Chevy and GMC trucks), old seals combined with cylinder pressure in the coolant can make the water pump leak, and once it is fixed, a blown head gasket is usually the next step in the excess pressure game. More than likely, your leaking water pump was an indication the truck was seeing excess pressure and was already on its way to blowing a head gasket—rather than something you did specifically during the install.
While some might say, “If that’s the case, I’ll just let my water pump leak,” that’s not really a solution, either, as the head gasket is probably already blown and will get worse regardless of whether you replace the water pump or not. While blown head gaskets can occur on any high-mileage Duramax, the LLYs are especially prone, due to their VGT turbo, which creates high drive pressure situations. While this provides great response over the life of the truck, it’s also harder on parts, and most LLYs will pop eventually.
