NEWS: Reverse Engineering

May 27, 2011
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The engine was an afterthought.
Miller Engine Exposed
Bill Castle was doing some work on a Bugatti Type 46 for a friend's widow, and the motor was rusting against a wall. Castle didn't know anything about it except that it was a straight-eight Miller of uncertain provenance, but that alone meant it deserved a reprieve from the junk pile. So he made the widow a modest offer, carted off the engine, and stashed it in his basement. And there it sat for decades, like a forgotten artifact in a museum that nobody visits, until Castle focused his attention on it in 2004.
"I didn't have anything else to do at the time," he recalls. "So I thought, 'Wouldn't it be nice to have a transmission?' After that was done, I thought, 'That was so easy. Let's do some more.' At the time, I had the engine on a three-wheel engine stand. So I said to myself, 'Why not build a four-wheel stand instead?'" This is Castle's wry way of explaining that he decided to fabricate an entire race car around the orphaned engine. Not just a showpiece, mind you, but a fully functional, dead-nuts re-creation of the Milton Durant Special that raced in the Indianapolis 500 in 1922 and established the direction that open-wheel racing in America would take for the next half century.
Castle is telling me all this in his customarily matter-of-fact manner while we sit in his garage next to the finished car, an aluminum bullet of breathtaking beauty. The engine is fully exposed, and the delicately finned case, slender pair of cam towers, quartet of carburetors, and artfully crafted exhaust manifold make it look like a piece of industrial art. Being of good Midwestern stock, Castle is prone to almost comical understatement, so he downplays the enormity of the challenges that faced him when he re-created--or "duplicated," as he puts it -- the Miller. But make no mistake: this was the kind of project undertaken only by a genius or a fool.
To begin with, the original car burned to the ground (although the engine survived) in a fatal wreck in 1922. There were no engineering drawings, so all Castle had to work with were a handful of period photographs and information gleaned from similar cars of the era. Still, he was determined to be as historically accurate as possible, which meant no cutting corners with Jaguar rear ends or modern brake kits. Oh, and he also planned to do everything himself. There were limits, obviously -- he doesn't own his own foundry, for example, and he farmed out the panel-beating and heavy-duty machining, but he did all of the design, the machining and fabrication of small parts, and the final assembly himself. Which brings us to the most remarkable aspect of the project: Castle was eighty-four years old when he embarked on it, and he'd just turned ninety when he drove the car for the first time last summer.
Miller Engine Side View
"What Bill did was inspirational," says his friend Gordon Barrett, a former Indy-car engineer and a world-class restorer in his own right. "He approached the project differently than most people. He needed a gearbox, so what did he do? He drew it on his computer. He built a wood pattern in his basement. He took it to a foundry and had an aluminum casting made. Then he took it back to his garage and machined it. He made his own gearbox! He did the whole car like that. It's a phenomenal achievement."
Castle is a white-haired man who wears glasses and -- on the wintry Indianapolis evening I meet him -- a flannel shirt tucked neatly into chinos. He moves and speaks deliberately, but there's no mistaking the energy and intensity of the focus he brought to this project. He didn't just open a parts catalog and order what he needed. He made his own shock absorbers. He made his own brake shoes. He made his own wheel hubs. And spring mounts, and front and rear axles, and gas and oil tanks, and so on and so forth. He's justifiably proud of his car. But he insists that what makes it unique -- in fact, this is the principal reason he decided to build it -- is the engine.
Now, any genuine Miller engine is special, and the most coveted model is the 91-cubic-inch supercharged jewel that set speed records that still seem incredible to this day. But Castle believes that his engine is what you might call the Rosetta Stone of Miller engineering. It's the oldest surviving, and quite likely the first, of the 183-cubic-inch straight eights that launched the Miller empire. A slightly modified version won the 500 in 1922 and formed the foundation of the Millers that dominated Indy-car racing for the rest of the prewar era. Castle's engine also established the fundamental architecture of the Offenhausers that won every 500 from 1947 to 1964 and continued to race at the Speedway until 1980. So it's not too much of a stretch to call his engine the most influential racing motor in American history.
Miller Engine Track
This project was particularly appealing to Castle because he's an engine man with lifelong ties to the Indianapolis Motor Speedway. He lives so close to the track that he can hear engines wailing around turn 4 when race cars are circulating. As a young man, he moonlighted as a race mechanic during four consecutive Indy 500s, wrenching on Offys derived from the Miller he owns today. And he spent his professional life as a chief project engineer for several projects at the nearby Allison plant, most notably the Allison Model 250 gas turbine, one of the most successful helicopter engines in aviation history.
Over the years, Castle has restored -- in some cases "resurrected" would be a more apt description -- a remarkable array of derelict machinery: A 1910 Hupmobile. A 1904 Oldsmobile. A 1914 Metz with friction drive. A seven-passenger 1912 Winton. A 535-cubic-inch 1908-9 Stearns with double chain drive. A 1929 Cadillac Sport Phaeton. A 1910 two-cylinder Buick. Parked on either side of the Miller in his garage are a 1911 Cadillac and a 1926 Bentley that he and his wife, Esther, have driven from Maine to Florida, Texas to Michigan. So for decades, the Miller engine sat in the basement, forlorn but not quite forgotten.
"I figured that, sooner or later, Dad would get it assembled and running," says Castle's son, Terry. Like his father, Terry is a retired Allison engineer and old-car restorer who owns a 1925 Bentley and a couple of MG TCs. "This seemed like a good, fun challenge. I've seen Dad take on all kinds of projects, and I've never been able to keep up with him. So this one doesn't surprise me too much."
Miller Engine On Track
Restoration projects begin with research. Fortunately, Castle was already a member in good standing of the minute but passionate cadre of historians who obsess over every detail associated with the life and work of Harry A. Miller, the lodestar of American prewar race-car engineering. By this time, Castle had realized that his engine was one-of-a-kind because it had a detachable head, whereas all subsequent Millers, and the Offys that followed, featured a monobloc design. Only two 183s were built in 1920 and '21 before Miller upgraded to a one-piece unit, and the other one had been cut in half in a racing accident. So now it was a matter of figuring out what chassis his 183 had been in.
Miller had come to prominence in 1917 as the builder of the Golden Submarine made famous by Barney Oldfield. Two years later, millionaire Cliff Durant -- a major-league sponsor and sometime racer who was the son of General Motors founder Billy Durant -- hired Miller to build a brand-new car. Dubbed the Baby Chevrolet in Durant's honor, the car was a gorgeous piece of work. (Newspaper accounts mistakenly referred to pieces made of manganese bronze as being gold-plated.) But the Miller-designed four-banger was a dud and the car was a slug, so the disgusted Durant either sold or gave it to his driver, Tommy Milton. Milton retrofitted the car with a Duesenberg engine. But even as he raced the Duesey, Milton commissioned a new straight-eight 183 from Miller.
With the help of engineer (and, later, Offy designer) Leo Goossen, Miller designed a double-overhead-cam engine that looked lovely and ran even better. (In a mildly upgraded version of this car and engine, Milton went an astonishing 151 mph on the dry lake at Muroc in 1924.) The engine was lighter than the contemporary Duesenberg and stouter than the fragile Ballot, so after overcoming teething problems, Milton and his Miller 183 spanked the competition. But a AAA ruling prevented him from racing it at Indy, so Durant got behind the wheel and finished twelfth. A few months later, Roscoe Sarles burned to death in the car when he crashed at Kansas City.
Miller Engine Hosing Down
Castle was convinced that the Baby Chevrolet was based on the Peugeot grand prix cars of the era. Many years ago, he'd taken measurements from the 1916 Indy winner and plugged them into computer-aided-design software. Castle also believed that the Baby Chevrolet was nearly identical to the next car built by Miller, the so-called T.N.T. This was owned at the time by Castle's friend, Dave Hedrick, another hard-core Miller-phile, out in Oregon. So Castle would print out full-size drawings of frame rails and axles and other components and mail them to Hedrick, and Hedrick would report back about what changes needed to be made.
"You should see the reams of correspondence between us," Hedrick says. "Some people just want their car to drive. But Bill wanted it to be historically accurate. Even I was surprised by his fanatical level of detail. I never would have gone to the trouble of making the front brakes work in the original manner. In fact, I probably wouldn't have duplicated them at all. You could fill an entire book with what he did with those front brakes."
Castle CAD'ed several brake components, made his own patterns, and had them cast at a local foundry. Then he figured out a way to make the brake pedal actuate all four brakes (via cables) while the handbrake outside the cockpit applied only the rears. The front spindle, meanwhile, confounded him so much that he built a wood model before he started cutting metal. "Normally," he says, "you have at least two degrees of kingpin inclination, but I kept having trouble getting the kingpin in that spindle. Finally, I pulled some pieces from the Speedway [restoration shop] -- they happened to be Duesenberg -- and lo and behold, they had zero kingpin inclination. Bright lights went on. With zero kingpin inclination, I could get the thing together."
The engine was easier than the chassis. Castle already had most of the pieces, not to mention an intimate understanding of how they were supposed to work. He made minimal concessions to modernity -- notably a fan to cool the motor and a starter so he didn't have to crank it by hand. But that was pretty much it. He replaced the pistons and bearings. He made a new distributor. He traded some parts for three authentic Miller carburetors and found the fourth, unbelievably, on the wall of a local tavern. "Thank goodness for that," he says. "Otherwise, I would have had to make it myself."
Miller Engine Posing
Castle used a handful of off-the-shelf components in the engine, but only after he'd massaged them to the correct dimensions. For instance, he bought valves designed for a modern Mazda engine because the stems and guides were the correct size. "They were the same as the original within two or three thousandths of an inch," he says. "I had to cut the length down and cut the head down and put keepers in. But I wasn't happy with the retainers. I found that I could use the retainers out of an Olds Aurora and machine them down to the diameter I needed."
Nearly five years after beginning the project, Castle was ready to start the engine for the first time, probably, in nearly three quarters of a century. I ask him if he was worried when he punched the starter. "No, not really," he says with a shrug. "We're used to working with antiques that haven't run in forty years. You tear 'em down and you rebuild 'em, and you think nothing of firing them back up again. As long as you've got water and oil circulating..." Terry adds: "An engine's an engine."
There's a YouTube video of Castle firing up the 183 in his garage while Terry watches (embedded below). The two of them look almost blase. The clip lasts barely a minute, yet it's mesmerizing. The camera pans around the engine, cradled between steel frame rails, revealing Harry Miller's signature synthesis of engineering necessity and aesthetic grace. At idle, it sounds like a V-8 with a hot cam. But then Castle jerks the throttle cable and the needle spins around the tach -- he tried seventeen of them before finding one he liked -- and you can't help but wonder what this car sounded like screaming around the wood banks of Beverly Hills and hammering over the bricks at Indy.
Miller Engine Fixing
After the video was shot, the sleek bodywork was completed by Denny Jamison of Automotive HammerArt in Indianapolis (forming some aluminum panels over wooden bucks built by Terry and his wife, Karen). Painted royal blue, the car ran nearly forty laps last summer at the Milwaukee Mile as part of the annual Miller Meet, and it's scheduled to return this summer. As I gaze at the car in Castle's garage, I realize it's almost exactly the same age that he is. And you know what? Both of them are still going pretty strong.

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