Randy Grubb’s Coachbuilt, Polished Aluminum V12 Roadster

At a crowded lunch table at the Las Vegas Convention Center in November 2014, Randy Grubb revealed his plan to assemble an aluminum-bodied roadster the likes of which hadn’t been seen in nearly 80 years. In attendance was legendary engine builder Ryan Falconer and representatives from Kugel Komponents, Dayton Wheels, and TCI. Armed with only a sketch and his reputation for metalforming, Randy explained his goal to pay homage to a pair of exalted French classics. It would be a massive undertaking, and Randy planned to finish the whole project in less than two years. Randy was confident and convincing. As he told us, he’d been shaping aluminum for years, this epic plan, “didn’t just fall out of the sky as my first attempt.” Everyone was on board.


“I’ve coveted one of these engines for 12 years. To finally be able to build one was a dream come true.” – Randy Grubb


It took four of them, but the bumpers are aftermarket aluminum pieces meant for a Volkswagen Beetle.
It took four of them, but the bumpers are aftermarket aluminum pieces meant for a Volkswagen Beetle.

The inspiration for the car had come months earlier, at the Mullins Museum in Oxnard, California. As Randy came across a 1937 Delahaye 145, his gears began turning. “It really struck me as perfection in a lot of ways” Randy said. The car represented some of the best technology the automotive world had to offer with a cutting-edge race chassis, an absolute monster of an engine, and a hand-built body that was striking from every angle. Its 4.5L V12 was an engineering marvel and led it to race victory and a million-Franc prize from the Automobile Club of France before two copies were sent to coachbuilder Henri Chapron to get fitted with bespoke coupe bodies. It was one of those two cars that Randy studied for hours at the Mullins. He had been looking for his next project and needed something that would test his skills. Since it would be two years of his life spent working on the single project, full-time, he wanted the result to be worthwhile. He’d already covered a lot of ground as a coachbuilder and an artist; this had to be big. As building an aluminum body from scratch weren’t enough of a challenge, Randy wanted to employ some of the unique design elements from another classic from the pantheon of French coachbuilding, the Bugatti Atlantic. Based on the Aérolithe concept that used a magnesium alloy body that could not be welded, the body of the Atlantic was formed with a prominent ridge as the panels were riveted together. The lapped panel construction would make the coachbuilding much more difficult. The edges had to end in the right place, exactly, and no welding meant that the panels would need to be constructed in huge sections, with little room for error. “It’s a ridiculous self-imposed challenge,” Randy told us, as each of the panels has a visible edge that would not be hidden by any kind of paint, let alone filler.

There’s no finish on the bodywork, just bare, polished aluminum.
There’s no finish on the bodywork, just bare, polished aluminum.

Randy had one engine in mind to power the roadster. He’s long had an affinity for V12 engines and has used them in several of his projects, yet he’s never had the opportunity to use a Falconer V12. It was designed by legendary engine builder Ryan Falconer, who had an Indy 500 victory and decades of engine development under his belt before he began work on the V12 in the 1980s. The engine shares many design elements with the small-block Chevrolet V8 including its 4.40-inch bore spacing although obviously many parts of the V12 are unique including the block, crank, camshaft, and cylinder heads. One look at the heads shows that they’re built for performance, with tall intake and exhaust ports for a more direct path into and out of the cylinders. The Falconer V12 typically displaces 600ci using 4.125-inch bores and a 3.75-inch stroke, the same as a Chevrolet 400ci small-block. For the roadster however, Randy wanted a smooth powerplant that would be easy to manage at low throttle that would still propel the car at sufficient speed to warrant its swoopy looks. Falconer Racing Engines delivered by building the engine to 500ci with a shorter stroke while still producing 648 dyno-proven horsepower.

This 500ci Falconer V12 is actually the smallest V12 Randy Grubb has worked with although it is by far the most power dense. Its still-large displacement combined with its 12 cylinders makes for a unique exhaust note. Under light throttle the engine sounds docile and it’s hard to identify. Once the dozen butterflies crack open a bit the V12 roar becomes more pronounced.
This 500ci Falconer V12 is actually the smallest V12 Randy Grubb has worked with although it is by far the most power dense. Its still-large displacement combined with its 12 cylinders makes for a unique exhaust note. Under light throttle the engine sounds docile and it’s hard to identify. Once the dozen butterflies crack open a bit the V12 roar becomes more pronounced.
The long fuel rails feature intricate carving. Also note the tapered spacer that moves the velocity stacks so that they’re just flush with the hood.
The long fuel rails feature intricate carving. Also note the tapered spacer that moves the velocity stacks so that they’re just flush with the hood.
There was no margin for error when cutting the holes in the hood. Randy made a tool that fit inside the throttle bore to mark the underside of the hood with the proper radius for the velocity stacks. Because the stacks are so close to one another, 1/8-inch 3003 aluminum was used in the center portion of the hood, the remainder of the hood, like the body, is half that thickness.
There was no margin for error when cutting the holes in the hood. Randy made a tool that fit inside the throttle bore to mark the underside of the hood with the proper radius for the velocity stacks. Because the stacks are so close to one another, 1/8-inch 3003 aluminum was used in the center portion of the hood, the remainder of the hood, like the body, is half that thickness.

After the meeting in Las Vegas, the order was placed for the engine in November of 2014. It would be the 52nd Falconer V12 built, although only a few had made their way into cars. While waiting for the engine to be delivered to his Grants Pass, Oregon, workshop, Randy was able to focus on the parts of the build that didn’t require an engine to be present. Still, the engine had been such a focal point that Randy began calling the car Falconer. When he told Ryan Falconer about this habit, Ryan was thrilled, and suggested adding Dodici, the Italian word for twelve.

Starting with a set of 20×8-inch Dayton spoke wheels set at a 120-inch wheelbase, several tires were mounted and mocked up before the right proportions were found. A 31-inch-tall tire was the perfect match, and from there the chassis design began. The 15.5-inch spindle height was the starting point as Randy drew the chassis on graph paper with plans to integrate Kugel Komponents independent front and rear suspension assemblies. Because there was no engine, he began on the frame’s perimeter and left the engine and transmission crossmembers for later.

Brakes are from Wilwood, with 14-inch rotors all around. The front uses six-piston calipers, four-pistons for in the rear. With the stack injection there was nowhere to put a vacuum port, so a Hydratech hydraulic brake system was plumbed to draw line pressure from the same pump that feeds the steering rack and pinion.
Brakes are from Wilwood, with 14-inch rotors all around. The front uses six-piston calipers, four-pistons for in the rear. With the stack injection there was nowhere to put a vacuum port, so a Hydratech hydraulic brake system was plumbed to draw line pressure from the same pump that feeds the steering rack and pinion.

From his graph paper plan, the dimensions of the frame rails were transferred to a CNC waterjet cutter that allowed the four sides of the complex three-dimensional frame to be cut from 1/8-inch steel sheet with corresponding tabs and notches cut that help the pieces index together for assembly. Randy welded the chassis rails up and then started building the buck for the aluminum body. Again Randy’s graph paper drawings were scaled up to full-size and the peaks and valleys of the design were transferred to sheets of medium density fiberboard (MDF). To get the proper flowing lines, randy used a section of PVC pipe as a giant French curve because it bends easily without kinking. Once the final shapes were drawn, the MDF was cut on a bandsaw and assembled to create a 3D skeleton of the body. Randy realized at that point that the three-dimensional shape wasn’t quite right. Something hadn’t translated. Some judicious trimming and reshaping resulted in a form that flowed properly and at that point the Falconer V12 arrived.


“I took the challenge of this car very seriously because it’s an iconic car.” – Randy Grubb


Checking the buck with the framerails, engine, and transmission mocked up proved that everything would fit, so construction began on the body tub. The majority of the body was constructed with 1/16-inch 3003 aluminum alloy although the cowl and cabin structure that the doors hinge from, and the structure of the doors themselves, was made from 1/8-inch 3003. Randy shaped the aluminum without annealing and TIG-welded the body tub and the frames of the doors and then put his welder away.

When we stopped by Randy’s shop in the summer of 2015 the engine and chassis were mocked up and the body tub and doors were under construction. The door frames and the tub are built using 1/8-inch 3003 aluminum that Randy hand-formed and TIG-welded over fiberboard bucks. No annealing was necessary.
When we stopped by Randy’s shop in the summer of 2015 the engine and chassis were mocked up and the body tub and doors were under construction. The door frames and the tub are built using 1/8-inch 3003 aluminum that Randy hand-formed and TIG-welded over fiberboard bucks. No annealing was necessary.
Randy explained that the fender will be just higher than the hood, to give the car an aggressive stance.
Randy explained that the fender will be just higher than the hood, to give the car an aggressive stance.
A touring roadster needs to have a measure of luxury, and a smooth-shifting overdrive with tremendous torque capacity was in order. A TCI 6X, a six-speed version of the 4L80E transmission, was chosen. It is operated by a custom shifter in the center console.
A touring roadster needs to have a measure of luxury, and a smooth-shifting overdrive with tremendous torque capacity was in order. A TCI 6X, a six-speed version of the 4L80E transmission, was chosen. It is operated by a custom shifter in the center console.

All of the polished aluminum that forms the body is riveted in place. No welding was used on any of it. That meant that Randy had to be extremely careful when cutting out his sheets for forming. Using 4×10-foot sheets, he was able to get some 11-foot long panels along the diagonal for the pieces that form the peaks of the front fenders. The metal shaping required to make each panel of the prominent fenders without welding is impressive, but the construction method was also used in the waterfall panel that runs the length of the cockpit and onto the rear deck. No cheating here.

Despite the car’s long wheelbase and big powerplant, it tips the scales at only 3,140 pounds. That’s less than a Porsche 911.
Despite the car’s long wheelbase and big powerplant, it tips the scales at only 3,140 pounds. That’s less than a Porsche 911.

Randy’s tools of choice for shaping the 3003 aluminum are his Marchant 12A shrinker and his Baileigh power hammer. The powerful shrinker pulls the aluminum smoothly and evenly without much marring, an important factor when the finish will be polished and bare. “Using it on 1/16-inch alloy it doesn’t even know it’s working.” Randy also has specific jobs where he calls on his 36-inch-throat English wheel, like the reverse curve where the fender meets the hood sides. For the fine tuning as the panels were lapped onto one another and held in place by Cleco temporary fasteners, Randy used a handheld, pneumatic planishing hammer to finesse the curves in the long strips.

The Delahaye Type 145 that inspired the Falconer Dodici used a 4.5L, three-cam V12 that was far less powerful, although quite successful in its era.
The Delahaye Type 145 that inspired the Falconer Dodici used a 4.5L, three-cam V12 that was far less powerful, although quite successful in its era.

While it makes up so much of the character of the car, the grille was practically a last minute addition. Randy’s initial grille insert looked like a 1937 Ford. As he put it, “it looked fine, but it was predictable.” Rather than focus on the grille and worry, Randy said he just let the problem of the grille design “marinate”. After several days, the solution came to him. “I try to bring a little glass into every project” Randy told us, and the solution came from a method used in glassmaking where parallel lines are pulled perpendicularly to create a feather shape. He even had a vase in his home that used the same technique.

Initially Randy thought a horizontal grille, like the one employed by the Delahaye 145, was the way to go on the Dodici. An initial mockup showed that the grille needed a bit more substance. A vase provided the inspiration Randy needed. The pattern on the vase resembled a feather, and was made by pulling a set of horizontal lines downward with a perpendicular brushstroke. To duplicate the look, randy used a remarkably simple round form mounted in his bench vise, which simultaneously crimped the end of the aluminum tube and gave it a smooth radius 90-degree bend.
Initially Randy thought a horizontal grille, like the one employed by the Delahaye 145, was the way to go on the Dodici. An initial mockup showed that the grille needed a bit more substance. A vase provided the inspiration Randy needed. The pattern on the vase resembled a feather, and was made by pulling a set of horizontal lines downward with a perpendicular brushstroke. To duplicate the look, randy used a remarkably simple round form mounted in his bench vise, which simultaneously crimped the end of the aluminum tube and gave it a smooth radius 90-degree bend.

The feather shape showed up in the windshield as well. To create the windshield frame, a solid plate of aluminum was cut using a water jet. Randy said the most difficult part was plotting the curve to match the cowl. Once the basic shape was cut, a handheld router with a dado bit cut the lip for the glass and a roundover bit smoothed the edges before polishing. The feather shape is also found in the stitching in the seat bottoms and backs that were wrapped in soft blue leather by Greg’s Upholstery in Grants Pass. The same leather wraps the door panels and the dash which features a custom-designed oval gauge cluster from Classic Instruments that houses for indicators for fuel level, coolant temp, voltage, oil pressure, and of course a speedometer and tachometer. There are also aluminum grab handles and vents for air conditioning. While the car doesn’t have a top, a blast of cool, dry air will be a welcome relief from the humid Midwest climate that the Dodici will call home.


“I’m going to Pebble Beach, but I can’t be on the grass yet. But the conversation is starting. “I’m knocking on the door, and I’m going to knock real loud.” – Randy Grubb


Classic Instruments gauges feature a custom face.
Classic Instruments gauges feature a custom face.

We asked Randy if he’ll miss having the car in his shop after it goes to the owner he didn’t seem to relish the upkeep of the bare-aluminum beauty. “I’ve polished it eight or nine times. The fun is in the next build and the next problem to solve.” True to his word, the next project is parked just outside, but it’s going to have to wait just a bit and Randy grudgingly admitted, “I’m gonna force myself to take a vacation.”

Randy found a taillight shape he liked and had a local foundry cast them in aluminum.
Randy found a taillight shape he liked and had a local foundry cast them in aluminum.
Here’s what they look like in as-cast state.
Here’s what they look like in as-cast state.
One of the few bits of exposed metal that isn’t aluminum, the Crafty B fuel filler has a base cast in brass.
One of the few bits of exposed metal that isn’t aluminum, the Crafty B fuel filler has a base cast in brass.
A bespoke enamel and copper emblem by jewelry artist Margarita Popova adorns the steering wheel. Smaller versions are on the center of each wheel.
A bespoke enamel and copper emblem by jewelry artist Margarita Popova adorns the steering wheel. Smaller versions are on the center of each wheel.
Trunk hinges and latch were both shaped by Randy on a belt sander from solid aluminum.
Trunk hinges and latch were both shaped by Randy on a belt sander from solid aluminum.
Source: hotrod.com

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