The Case For Plastic Car Engines - Matty Holtzberg, Composite Castings
Forty years ago, Matty Holtzberg, a young car enthusiast with a burning curiosity, visited the Hackensack, New Jersey, public library for a little light reading. His discovery - a technical journal article about a new plastic so robust that it could be used inside a car engine - set the course for his life's work. And thanks to Holtzberg's perseverance, the way car engines are produced may be drastically changed.
Holtzberg soon obtained a sample of the fantastic French-engineered plastic and tried it out. He had the slug of material machined in the shape of a piston which he installed in a friend's Austin Mini for a trial by fire. Amazingly, the engine started and ran for several minutes before the heat of combustion flambéed a hole in its crown.
Undaunted, Holtzberg pressed on. During the 1970s, he manufactured and sold plastic connecting rods to racers wishing to extend their rpm reach with the lightest possible reciprocating parts and plastic pistons, now equipped with heat-resistant aluminum crowns. His parts worked as intended.
In 1979, with backing from Amoco Chemical, he founded Polimotor - short for polymer motor - to engineer the first composite-plastic-intensive engine. Holtzberg's seminal design was, in effect, a clone of that day's Ford Pinto 2.3-liter four-cylinder. Instead of the production engine's cast-iron block and SOHC head, Holtzberg's design incorporated reinforced plastic for the block walls, piston skirts, connecting rods, oil pan, and portions of the cylinder head. Bore surfaces, piston crowns, and combustion-chamber liners were iron or aluminum. The crankshaft and camshaft were standard Ford production components. The weight savings was phenomenal: compared to the stock 88-horsepower Pinto engine's 415 pounds, Holtzberg's engine weighed less than 200 pounds.
AUTOMOTIVE INDUSTRIES magazine reported on this development shortly after Holtzberg's first engine ran in a 1980 cover story. By the time Popular Science picked up the scent two years later with a second cover story, he had gone beyond Pinto power to build a twin-cam, 16-valve racing engine that produced 300 horsepower and weighed 152 pounds. With Amoco backing, his team campaigned a Lola T-616 in IMSA's Camel Lights road racing series, scoring two third place finishes during the 1984 and 1985 seasons. The only catastrophic failure occurred when inadequate lubrication resulted in a thrown connecting rod during a race at Watkins Glen. That particular part was a metal design purchased from a respectable supplier.
In 1994, Derrick Young won the British 2.0-liter hill climb championship with a car powered by one of Holtzberg's engines.
PopSci quoted Ford officials expressing interest in the Polimotor but, according to Holtzberg, that was smoke. "They reaped ample publicity related to my work but actually contributed nothing," he explains. Automobile's further digging did turn up two Ford engineers who believed that the technology was worth examining but they were stopped in their tracks by a superior who wanted nothing to do with anything this unprecedented and risky.
Detroit's deaf ear forced a change in Holtzberg's course. Instead of playing with a potpourri of plastics, including carbon fiber for the block walls and Amoco's Torlon thermoplastic for pistons and other parts, Holtzberg shifted focus to a less expensive and more versatile phenolic reinforced with fiberglass because these materials are more suitable for mass-produced blocks. Ironically, phenolic resin was the first polymer ever developed.
Between 1907 and 1909 Belgian chemist Dr. Leo Baekeland developed Bakelite, the first plastic made of synthetic components. This is the stuff of 78-rpm records, billiard balls, dial telephone housings, and Mahjongg tiles. Phenol, which comes from benzene is reacted with formaldehyde, which comes from methane, to yield phenolic resin which is also the glue that holds plywood together.
Phenolic resin has a high carbon content which provides a remarkable resistance to heat. When combined with carbon fibers, it's tough enough for use in rocket booster nozzles. Phenolic also serves as a binder in the manufacture of carbon-ceramic brake rotors.
Holtzberg was not the first to discover the virtues of phenolics for automotive use. During the 1930s, Henry Ford began combining soybean meal with this resin to mold the first plastic horn buttons, shift knobs, door handles, and timing gears used in mass production. When his supply of steel was under threat during the early stages of World War II, Ford had an entire car body made of plastic. At a 1941 gathering, he made news by taking a whack at his personal Ford equipped with a soybean-and-phenolic-resin decklid. When the ax bounced off inflicting minimal damage, his durability point was proven; in addition, Ford was enthused by plastic's potential weight and cost savings.
Amoco sold its Torlon business to Solvay Advanced Polymers years ago and is no longer in the Holtzberg picture. His latest strategic partner is the Huntsman Corporation of Houston, Texas, a global chemical company with 12,000 employees, $10-billion in annual revenue, a proven track record supplying the auto industry, and a burning desire to help Holtzberg succeed with its phenolic and epoxy resins.
James Huntsman, the vice president of the advanced materials division, acknowledges that it's a long and difficult task to convince any manufacture to replace conventional metal pouring - a 6000-year-old technology - with the patented Holtzberg Composite Casting approach. Nonetheless, this partnership firmly believes that Honda, McLaren, or any progressive auto maker should give this technology a serious look. Huntsman adds, "Considering today's intense competition, the race to higher fuel efficiency, and the need for environmentally friendly manufacturing, we're convinced that the time is right for a composite engine."
Plastics have made major inroads in automobiles with the average car now equipped with over 300 pounds of plastic trim, bumper fascia, and powertrain parts. Notable applications are the Corvette's fiberglass-reinforced body panels and chassis springs. Plastic fuel tanks and intake manifolds are practically universal with cylinder head covers and oil pans the next in line.
Formula One (F1) is an excellent place to scout composite-plastic applications because technology that's successful there eventually trickles down to premium sports car if not mom and pop sedans. Carbon-fiber reinforced monocoques were introduced in F1 in 1981 and made the leap to top Bugatti, Ferrari, McLaren, Mercedes, and Porsche road cars several years ago. Engine components made of composite plastic - blocks, heads, pistons, etc - are attractive but currently off-limits according to current rules for cost reasons. Ferrari and others have raced with carbon-fiber and titanium transaxles for nearly a decade. These parts have survived astronomical mechanical loads and sustained 300-degree F. operating temperatures.
Holtzberg currently has 17 licensees that use his patented resins and processes to manufacture rapid prototyping parts that are used to expedite the engineering and development process for regular production models. Ed Graham, the engineering manager at the Pennsylvania firm ProtoCam, is sold on this technology. "We've been making intake manifolds, fuel rails, and other parts for three years with the Composite Casting process," he notes. "Post-casting machining is practically eliminated because, unlike metal castings, the plastic parts don't shrink when they cool. Thermoset phenolic is strong and has excellent heat resistance. Our customers have been quite satisfied with the prototype parts we've supplied to them."
Numerous mass-production opportunities exist for composite-plastic castings. This could be an excellent way to put any large-displacement motorcycle on a diet. The range-extending four-cylinder engine that will initially power the Chevrolet Volt has a cast-iron block which seems ripe for replacement with something significantly lighter. Your weed whacker and chain saw would be less of a handful to operate with their aluminum crankcases replaced by composite-plastic moldings or castings.
So keep an eye on Matty Holtzberg and his cause. The way he sees it, reinforced-plastic engine blocks and transmission housings are clearly the next chapter in the automotive evolution story following wood, iron, steel, aluminum, and magnesium materials. He just might be right.