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The Craziest Diesel Swaps We've Seen

Dec 28, 2023

Diesel of the Week is presented by

As the old Farmers Insurance slogan goes, "We know a thing or two because we’ve seen a thing or two" – and believe us, we’ve seen a thing or two. All sorts of interesting and unique engine builds come our way, whether from builders contacting us directly or the team scouting out machines at race events, shows, and machine shops across the country. And yet despite this, we still get caught off guard from time to time by the sheer creativity of the engine and automotive community.

The diesel side of things in particular has changed so much over the last two decades, with technology and ingenuity developing fasting than expected. 2,500-3,000 horsepower diesel dyno pulls were unheard of a few years ago, but now we’re seeing them pretty regularly at the competition level at events like UCC. It's a great time to be a diesel engine fan.

And aside from strictly horsepower gains, it's also just interesting to see what people are coming up with in their backyards or in the shop. Diesel engine swaps are something we always have our eyes on as it's not something you’re going to be seeing every day. And to clarify, we don't mean dropping a Cummins engine into a Ford truck – that's been done, and builders have been doing it for years. That's not to say it isn't cool in its own right.

But today, we’re specifically talking about the weird and the wild – things you aren't going to see out on the street very often. This could be diesel engines being dropped into a stock gas engine vehicle, or simply a vehicle that you wouldn't guess to have a fully a fully spec’d performance diesel under the hood.

Since we just finished up our May/June print issue which specifically covers all things diesel, we compiled a list of some of the weirdest, coolest, and most impressive diesel swaps we’ve seen in the past couple years and featured in our Diesel of the Week series.

1988 Ford Mustang – 5.9L 12-Valve Cummins Engine

Aptly named the "Coalstang," this crafty backyard build was thought up and put together by Darcy Hanlan, a Canadian heavy machine maintenance operator who has deep family ties to NHRA racing. It's important to note that most of the builds featured on Engine Builder aren't cheap, to say the least, but Hanlan's build is proof that you can build a formidable on racing machine on a budget.

For only $4,300, this Mustang can complete a quarter mile run in just 10.6-seconds. Much of that is thanks to the weight reduction – that car weighs only 3,000 lbs., making it lighter on the front axle than it was from the factory. That's impressive considering the beefy 12-valve 5.9L engine under the hood.

Much of the engine was left stock, including the block with 14mm main studs, the camshaft, connecting rods and pistons. The factory head gasket and head bolts were torqued to a higher specification and the mechanical lift pump was upgraded "with a few tricks."

Many of the added components were used parts obtained from Power Driven Diesel (PDD), aiding him in his cost-efficient endeavor. PDD 5×0.018 injectors and a 215-injection pump off a ‘98 Dodge truck work to send fuel into the combustion chamber.

Hanlan also added a Turbosmart wastegate, a JEGS electric water pump and a Fluidampr. As for the turbo system, he opted for a single JM Turbo wastegated HX40 with a 60mm compressor and 64mm turbine. He also uses a hefty amount of nitrous to keep everything spinning right.

Much of his build was documented from start to finish on his Instagram page, with coverage on Facebook and YouTube as well.

2010 Nissan R35 GT-R – Compound Turbo 6.0L Powerstroke Engine

The reverence for the R-35 GT-R in the car community simply can't be stated. The GT-R was developed with the idea of outperforming more powerful and expensive cars while still being a complete package. Capable of defeating the C8 Corvette, dishing out punishment to a Porsche 911 Turbo and a fondness for frying some lower powered Ferraris, the Nissan R35 GT-R is a true supercar killer.

So, it might come as a surprise to many that the team over at LYFE Motorsport partnered with Riff Raff Diesel to build a diesel-powered GTR that could complete at the Pikes Peak International Hill Climb. The result was an amazing package.

How can a 2004 6.0L turbo diesel V8 compare to the VR38DETT that was originally under the hood? Surprisingly, the numbers aren't so far off. The VR38DETT was bored out to 4.0L and force fed by twin Garrett GTX3076 turbos; on the dyno it made around 1,200 horsepower. Although the official numbers were never released, the 6.0L Powerstroke made in the neighborhood of 850-950 horsepower and well over 1,000 ft.-lbs. of torque – and that's on fuel alone, before nitrous enters the equation.

The factory block is fitted with a set of Mahle stock-bore, ceramic-coated pistons with valve reliefs cut in. The valves are operated by a Stage 2 billet camshaft, and it hits the Anderson HS lifters using Smith Brothers pushrods. A set of ARP 625+ head studs contain the heads and the valvetrain is covered by Riff Raff Diesel billet valve covers.

Fueling this setup is a set of 250cc 100% injectors and a compound turbocharger setup with a KC Turbo Jetfire Stage 1 as the primary and a BorgWarner 80mm atmosphere turbo working as the secondary to force air into the ODawg 6.4L inverted intake manifold. The intake system is so massive that its tubing is mounted inside the cabin, directly in front of Powelson.

A water sprayer is added in front of the intercooler to assist with keeping the charger air cool, making up for the lack of air as the car climbs in altitude up Pikes Peak. The Powerstroke engine is oiled thanks to a Terminator T500 high-pressure oil pump feeding 10w40 diesel oil. This is sent through a custom dry sump system that required the use of a Kill Devil Diesel dry sump front cover and custom-made oil pan.

1946 Chevrolet Cabover – P-Pumped 12-Valve 5.9L Cummins Engine

In case you’re unaware of Kenny Hauk, his business Hauk Designs and his show on Amazon Prime called Hauk Machines, now in its fourth season, this is your wakeup call to check it all out. Kenny Hauk and his team create one-of-a-kind, custom builds for any and every application.

Back in May 2021 when the Engine Builder team traveled to Indianapolis to take in the Ultimate Callout Challenge, we also got to walk around the DPI Expo where, tucked away in the last row of exhibitors, was one of the coolest trucks at the entire show – Hauk Designs’ 1946 Chevy Cabover beer tanker.

Clearly, the Hauk Designs tanker is big, beautiful and it serves beer. How can it get better, you ask? It's powered by a P-pumped 12-valve 5.9L Cummins engine that also has a compound turbocharger arrangement. Putting the power to the ground is a CA Conversions Allison transmission that fits right in with the old-school style. We don't know too many details about the particulars when it comes to the engine, but we’re sure it makes more than enough power to boot!

Toyota Supra – 5.9L 6BT Cummins

The JDM scene has grown into a force to be reckoned with, and today, people across the globe soup up Japanese sports cars from the ’80s up through the 2000s. There are a myriad of iconic cars which fit into this category, including the Honda NSX-R, Mazda RX-7 and the Nissan Skyline. But one of the greatest of all time is the Toyota Supra, known for its popular 2JZ-GTE engine and borderline infinite amount of tuning capability. Its hero status in the Fast and the Furious franchise also gave it a notable bump in admiration.

In every community, however, there are purists — and the JDM subculture is no different. The Supra is so heralded that obscure customization of the platform is sometimes seen as blasphemous. But a diesel-swapped Supra is just too cool to judge.

The Cummins engine under the hood was originally a 600-hour mil spec 250-hp unit with a P7100 fuel injection pump that owner and builder Ashley Whitsey obtained as a surplus.

The engine features an ATS manifold with an HX40W turbo, a large intercooler and piping, dual plane intake, a Fluidampr and new fuel pump, PPD fuel injectors and delivery valves, and an AFC controller for in-cab fuel tuning.

The engine is paired with a 5-speed manual gearbox out of a Leyland DAF-45 and a Lexus IS220d differential.

2004 Lamborghini Gallardo – Twin Turbo 5.9L Cummins

In Eastern Texas, the experts at 1 Way Diesel Performance are renowned for their expertise in diesel vehicles. They provide various services to their customers, including manufacturing parts, repairing engines, and creating fully customized builds. Some of their exceptional builds have even been showcased on the Motortrend show "Texas Metal's Loud & Lifted," which explores emerging diesel customization shops in Texas.

Interestingly, in a recent episode, the spotlight was on one of 1 Way Diesel's builds, despite it not fitting the typical "lifted" style. In fact, there was hardly any space to slide a playing card beneath the frame of their featured car. This particular vehicle happened to be a 2004 Lamborghini Gallardo, equipped with a powerful 5.9L common rail Cummins engine positioned at the rear.

Although primarily serving as a shop vehicle, this project car underwent a three-month transformation and will occasionally be taken to the drag strip. Consequently, it received more than just a standard diesel engine swap. The skilled team at 1 Way Diesel went the extra mile by upgrading the connecting rods, camshaft, main studs, and head studs. Additionally, they incorporated a ported cylinder head with upgraded springs. To generate approximately 1,000 horsepower, surpassing twice the output of the stock 5.0L V10 engine found in the Gallardo, they installed larger injectors and implemented a unique twin-turbo setup.

1941 Chevrolet School Bus – P-Pumped 12-Valve 5.9L Compound Turbo Cummins Engine

Between running a construction company, operating a bar, owning a carwash, and managing several rental properties, he still found time to commit to his passion project – building a chopped and lowered rat-rod ’41 Chevy school bus with a P-pumped 12-vavle 5.9L compound turbo Cummins engine.

The pair traveled 700 miles away from home to bid on an old Ford bus. After being out-bid, they came home with their Chevy bus for a cool $2,700. The next step was making some refurbishments and finding a proper engine to place under the hood.

Most of the machine work was undertaken by nearby Quality Engine Machine Shop. Drew DeClerck of DeClerck Custom Machine assembled the refreshed 5.9L and Scheid Diesel cut the block for fire-rings.

Inside, the Cummins received ARP main and head studs, a Hamilton 188/220 hot street camshaft with tappets, heavy-duty pushrods, and 180-lb. valve springs. The build also received port and polish work performed on the head.

Bliesner put cam bearings in it, head studded it, and got the pump built to 4,500 rpm with a custom cam and 180-lb. valve springs in the head.

A high-pressure wastegated S363 sits underneath the hood, while a BorgWarner S472 non-wastegated atmosphere charger sticks out the top. The S472 kicks in at around 25 psi of boost. As for the fuel, a Scheid Diesel P7100 fuel injection pump with custom-bent stainless injection lines and 5×13 injectors were installed. A Summit Racing 20-gallon aluminum fuel cell and a homemade fuel system with a FASS 260-gph lift pump power the engine.

With all of its upgrades, the engine puts out around 650-hp and 1,200 lb.-ft of torque.

Diesel of the Week is sponsored by AMSOIL . If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].

1988 Ford Mustang – 5.9L 12-Valve Cummins Engine 2010 Nissan R35 GT-R – Compound Turbo 6.0L Powerstroke Engine 1946 Chevrolet Cabover – P-Pumped 12-Valve 5.9L Cummins Engine Toyota Supra – 5.9L 6BT Cummins 2004 Lamborghini Gallardo – Twin Turbo 5.9L Cummins 1941 Chevrolet School Bus – P-Pumped 12-Valve 5.9L Compound Turbo Cummins Engine Diesel of the Week is sponsored by AMSOIL . If you have an engine you’d like to highlight in this series, please email Engine Builder Editor Greg Jones at [email protected].