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Loco Hauk Steam-Powered 6x6 Jeep JK Built by Kenny Hauk at 2017 Easter Jeep Safari in Moab

Steam-powered 6x6 Wrangler

Rick PéwéPhotographerTraci ClarkPhotographer, WriterTom KimmelPhotographer

“Hell on wheels” doesn’t begin to describe the latest creation by Kenny Hauk, owner of Hauk Designs and River Raider Off-Road in Chambersburg, Pennsylvania. This faux locomotive weighs in at six tons—a mere 12,000 pounds of smoke-and-steam-belching Jeep Wrangler. When we saw it chug in to Moab, Utah, during Easter Jeep Safari we knew we needed a closer look.

At first glance, some might think this 2008 Wrangler Unlimited may have been rear ended by a steam engine, but there is much more to this Jeep than meets the eye. Watching Kenny and the crew bring it to life is an experience that will stay with you for a very long time. You hear the burner ignite, then a faint shimmer of heat is detected above what appears to be a giant rolling barbeque on 41.5-inch Pit Bull Rockers. Slowly the black coil of smoke increases. A look to the hood shows small wisps of steam; then it lurches to life. Imagine the Chitty Chitty Bang Bang movie from your childhood, but on a grander scale as it chugs along like a freight train.

Under the hood of this behemoth is what some may consider a relatively tiny engine—a 100ci V-4 single-acting, trunk-piston, poppet-valve uniflow steam engine. The design is based on the center two throws of a small block 272ci Ford crankshaft. This engine was designed and built by Charles Keen for the Keen Steamliner 2 automobile sometime around 1960. It is capable of 130 to 140 horsepower. While that’s not many horses under the hood, it does generate roughly 2,500 foot-pounds of torque. The factory NSG370 6-speed manual transmission and NP241 transfer case were left in play, but the engine only allows for one high forward, one low forward, and one reverse gear. Loco Hauk is capable of speeds between 50 and 60 mph, and it is most efficient at a boiler pressure of 800 psi when a drier type of steam is created. In the steam-powered world, more boiler pressure equals more horsepower.

The standard 16-gallon fuel cell has been converted to run on kerosene, as that is burned to heat the boiler. There is a 55-gallon water tank mounted in the area behind where the rear seat was originally located, and the boiler holds an additional 20 gallons of water. Fuel economy, or shall we say water economy, isn’t its finest attribute; while at 500 psi and speeds of 30 to 35 mph, 55 gallons of water will only transport you 1 to 1.5 miles. We could fill an entire issue with all the cool features and tech on Loco Hauk, but unfortunately, we don’t have the room within these pages. We suggest you tune in to the History Channel and watch Road Hauks, Kenny’s new reality show. New episodes began in August and the Loco Hauk build aired in fall of 2017. We did ask Kenny the question on everyone’s mind: Why? He replied with a smile, “it’s the most insane thing we could come up with.”

Why This Jeep

Fascinated by the odd and unique, we knew this Wrangler would deliver that and more. Not only is it impressive to look at, but its creativity, science, and design caught our attention. While it may not handle the hardcore trails with ease, it has opened doors for learning more than we ever dreamed about the world of steam power that had its place in the Old West and conquered wild country and blazed new trails. We look at this Jeep as a bit of modern rolling history.

Hard Facts

Vehicle: 2008 Jeep Wrangler Unlimited 6x6
Engine: 100ci V-4 single-acting, trunk-piston, poppet-valve uniflow steam engine
Transmission: NSG370 6-speed manual
Transfer Case: NP241
Suspension: BDS 4-inch 4-link and Fox shocks
Axles: TeraFlex D60, 3.73 gears, Auburn Gear Max Lock locker (front); Ford 9-inch pass-through axle 3.70 gears (mid drive axle); TeraFlex D60, 3.73 gears, Auburn Gear Max Lock locker (rear)
Steering: Modified Toyota steering box with Redneck Ram hydraulic assist
Wheels: Grid Off-Road GD-1
Tires: 41.5x13.50R17 Pit Bull Rocker

Steam Science
A steam power system has many components, and so it is not the engine itself that is complex to build. There is the burner and the boiler (or steam generator, as we like to say). The steam flow is: intake from a poppet-valve, cam-controlled setup like a flat-head with the poppet valve right beside the head and a small channel taking steam from underneath the valve into the clearance volume. The exhaust is exactly like a two-cycle engine with ports drilled into the side of the cylinder at BDC (bottom dead center). About 30 percent of the steam stays in the cylinder after the pistons close off the exhaust ports. This is then compressed up to about boiler pressure, depending on the clearance volume, and this is fine for efficiency reasons. There are twice the power strokes per revolution in this steam engine than in a four-cycle engine, so it only needs half the displacement. Steam at about 800 psi and 800 degrees F has a higher MEP (mean effective pressure) than is found in a naturally aspirated four cycle engine. So, theoretically a steam engine can make more than twice the horsepower for its displacement than a regular engine.

The camshaft is three-dimensional, meaning that there are four grinds for each cam follower/push rod/poppet valve. There is an inclined step between these grinds so the camshaft can be slid with a long lever. There is a subtle and very clever aspect to Keen’s design as the valves are slightly offset, about the width of the big end of the connecting rod, so that any one cam grind will actuate the two opposing cylinders. Therefore, only two sets of cams are needed for the four cylinders. The camshaft is conventionally located in the valley of the V. The cam grinds are long-cutoff reverse, long-cutoff forward, medium cut-off forward and very short cut-off forward. Cut-off is the standard steam terminology for the dwell time of how long the intake valve is open. For good fuel economy the intake valve is kept open for about 15 percent of the stroke so that the steam gets to expand and give up most of its power on the down stroke. On the other hand, if the valve is kept open most of the time, say 80 percent, then there is full pressure on the piston for almost all of the down stroke and more torque is made. This is what happens when starting from a dead stop. Once moving, and when the engine is turning more rapidly, less torque is needed so the cam is shifted. There are detents on the shifting rod to indicate each of the cam positions.

The reason for the poppet-valve intake and two-cycle type of exhaust (known as a Unaflow or uniflow engine in steam-speak) is for both simplicity in making the valve train and for some very subtle thermodynamic efficiencies having to do with conserving heat because the steam cools down rapidly as it expands, thus cooling off the surrounding cast iron.
—Courtesy of Tom Kimmel