HUMMIN’ CUMMINS

SAND BLASTING IN A 1,000-HP DIESEL HUMMER H1

Steve Ortner, of Belleville, Michigan always wanted a Hummer. When he did finally get the chance to buy a ’94 civilian-spec Hummer H1 he was quite overjoyed. But there was a problem. “The Hummer had a naturally aspirated 6.2L engine in it, and it was so, so slow,” Ortner says. “There were times on hills you didn’t think it would make it up to the speed limit!” He for sure had the vehicle he’d always wanted—but it was powered by the wrong engine.

12-Valve Transplant

“I’d always liked stuff with power and reliability, so the 5.9L 12-valve Cummins was an obvious choice,” Ortner says. After acquiring an engine from a Fed-ex truck he was off to the races. Since he knew he wanted a lot of power he started with the engine block and worked his way up. The Cummins block was fitted with 14mm ARP main studs and a girdle that’s based on a Industrial Injection Gorilla Girdle but was modified at Ortner’s machine shop, Mountain Machine. He kept the factory crank, but

from Wagler Competition Products, along with Diamond pistons. A 188/220 camshaft from Hamilton Cams was added, and the block was machined to accept 14mm head studs. After the bottom end was assembled Ortner opened up the Hamilton Cams catalog again for one of their Street heads, along with a valve spring package and pushrods.

Compounds

While a single turbocharger would have been the easy way to go, Ortner was more concerned with response and power. So compounds it was. With a high-rpm capable engine, Ortner went with a 66mm turbocharger as his smaller turbo, and a monster 88mm Borgwarner SX-E for the large turbo. He also built a custom intercooler out from a bare core and jacked the fuel to the stratosphere with a 13mm P7100 pump from Farrell Diesel Service, 5x0.025-inch injectors from Power Driven Diesel, Scheid

Diesel 0.120-inch injection lines and a 220-gph FASS lift pump. Estimated horsepower is somewhere around 1,000 hp even with the 13mm pump turned down.

Power Transmission

Transmissions can be a large and troublesome part of diesel swaps, but in this case Ortner lucked out. A GM 4L80E easily fit in the transmission tunnel, and he was able to adapt the Cummins engine to the transmission via an adapter plate of his own design. A Cummins-to-gm flexplate was also used as the final piece to hook everything together. Now, GM 4L80E transmissions are a good design for diesels because they use an overdrive gear, are relatively light and can be built to be very strong. For a racing gearbox that could handle the engine’s monster torque, Ortner dropped the electronic “E” and went with a full manual valve body and performance transmission from J&H. The 4L80 features raised line pressures, aftermarket shafts and a tough Yank Performance torque converter that stalls at about 2,200 rpm. Used in off-road race trucks, this converter is one that’s built to handle abuse.

Suspension

The suspension was another area where Ortner turned to the offroad racing industry, as it’s not like every parts store carries lift kits for Hummers. He wanted his H1 to be plenty capable, so he went with a Rod Hall Products long-travel spring and shock package that was designed to give the truck a couple inches of lift along with useful travel. The rest of the drivetrain was also suitably reinforced, with a transfer case out of an armored Humvee and ARB air lockers front and rear that work with the factory gearing. Ortner also upsized in the wheel and tire department with 37-inch Pitbull Rocker XOR tires mounted on 17x9-inch Method Race Wheels beadlocks.

Dream Truck

When he was finished building out his innovative Hummer, Steve Ortner now had enough power to pass cars on the highway—and just about everything else. He spends a lot of time in the sand where the Hummer really shines, as its independent suspension, huge wheels and tires and all that diesel torque make for just about the perfect combination. So what’s next? “I need to find a

four-wheel-drive dyno in the area and start really leaning on it,” he says. He’s also attracted enough interest in his personal Hummer conversion that he’s now building examples for customers. “I had a lot of friends help out with this one,” Ortner says. “Casey Curtis, Ed Larsen, Carl Sparks and Chris Reiter, and we decided we wanted to do more. There are about three in the shop right now—and I don’t see things slowing down any time soon.”

ESTIMATED HORSEPOWER IS NOW SOMEWHERE AROUND 1,000 HP.

 Performing a Cummins swap is hard enough, but Steve Ortner went the extra mile and built his 5.9L 12-valve for monster power. The engine pushes an estimated 1,000 hp and 1,700 lb-ft of torque through a J&H 4L80 to the Hummer’s all-wheel-drive system.

 Since the Hummer came from the factory with a diesel powerplant, there was a decent amount of room for the swap. Many parts like the engine mounts and transmission adapter were made in Ortner’s own shop, Mountain Machine.

 The fueling system is perhaps the most over-built aspect of this Hummer. Fuel first gets sent to the engine via a 220-gph FASS pump, where it’s then fed to a 13mm P7100 injection pump from Farrell Diesel Service and 5x.025-inch Power Driven Diesel injectors. All told, Ortner figures he has about 1,500 hp worth of fuel on board.

 Since he planned for the engine to spend a lot of the time in sand, Ortner had to make sure to size the turbos correctly. He didn’t want to go with a big single due to the lag, and instead went with a compound setup that starts with a 66mm S300 turbo from Borgwarner.

 Reliability was priority number one so Ortner reinforced his engine everywhere he could, with ARP studs in the mains, the rods, and of course the head. He even went a little further with the head studs, choosing ARP’S Custom Age 625 material in order to prevent any issues at high boost.

 The number of custom parts on this Hummer is practically endless. From the engine to the cooling system to the drivetrain, there’s something special virtually everywhere you look.

 The intercooler is just one of many pieces of the puzzle needed for the Cummins swap. Ortner wasn’t able to find anything to fit the bill from any catalog, so he bought an intercooler core that roughly matched the flow specs from the big turbocharger and got to work fabricating end tanks that would fit the engine bay confinements on the Hummer.  An onboard air system is a big part of Ortner’s creation. The lockers and tires all need to be aired up and down and activated and deactivated for the sand, so he installed an air compressor system from ARB to get the job done.

 The Hummer’s rear axle has been fitted with an ARB air locker to help with traction. Unlike virtually all diesel pickup trucks, the rear suspension is an independent design and is only able to survive thanks to its incredible strength. Ortner reports that the factory gearing works well with the diesel thanks to the engine’s high-rpm operation and the overdrive transmission.

 The larger turbo is an 88mm with the new SX-E technology from Borgwarner. It’s the prime air mover in the system, which produces about 80-85 psi of boost. Ortner says the Hummer really starts to come alive at around 2,500 rpm and will pull all the way to 4,500-5,000.

 The suspension on an H1 Hummer is truly unique and one of the toughest independent suspensions around. The battle-tested design is AWD (allwheel-drive) without a 2WD option, and this one has been supplemented with a Rod Hall long-travel kit.

 The first clue that this Hummer is diesel-powered could be the 5-inch exhaust stack, which is routed up and out of the port where the factory air cleaner used to reside.

 With a small fortune invested in the engine and transmission, Ortner wanted to keep an eye on everything. He used the factory Hummer pillar to mount four Autometer gauges, plus a center tachometer that lets him keep the engine in its sweet spot.

 Custom black vinyl was cut specifically for this Hummer and covers virtually every square inch of its interior surfaces.

 As with the front, the stylish rear bumper was fabricated at Ortner’s shop and is just one of the many handmade parts on this vehicle.

 This cool central tire inflation system (CTIS for short) allows Ortner to air the tires up and down without ever leaving the comfort of the Hummer’s cabin.

 Ortner went tall by wide for his tire choice, and the aggressive 37x12.50-inch Pitbull Rocker XORS mounted on 17x9-inch Method Race Wheels beadlocks are designed more for the sand than anything else.

 The front bumper is a Steve Ortner creation and is augmented with a set of KC Hilites LED clusters and a 15,000-pound Warn winch.