Corvette Chassis History Pt. 2: C2/C3 1963-1982

The C2/C3 Corvette Chassis That Zora Built

Dateline: 7.31.19 – As seen in the January 2019 issue of Vette magazine, Illustrations by K. Scott Teeters – When the 1963 Sting Ray made its public debut in September 1962, it was a total, “WOW!” And it wasn’t just the Corvette’s stunning new looks; it was the all-new chassis and suspension. By late 1959 Zora Arkus-Duntov was in charge of Corvette engineering. When Bill Mitchell’s design team started work on project XP-720 (the all-new Sting Ray), Duntov was called in to set the parameters for an all-new chassis. The completed Sting Ray looked like the sportscar from another planet and the chassis had everything except four-wheel disc brakes. Today the running chassis looks like a buggy compared to the stout aluminum, steel, and magnesium chassis’ of the C5, C6, and C7 Corvettes. But in 1963 the top-performing L84 Fuelie engine only had 360 “gross” horsepower and 352-LB/FT of torque putting power-to-the-ground with 6.70×15 bias-ply tires. That’s not much twisting on the chassis, so the chassis was more than adequate.

Even when the high-torque big-blocks arrived in 1965, for street use, the Duntov chassis could handle the job. The design didn’t start to show its limitations until the 1968 L88 racing Corvettes with wide tires started competing in long endurance races. Tony DeLorenzo once commented that after long 12 or 24-hour races, their Corvettes needed new frames. Their solution to this problem was a Logghe Brothers full welded-in roll cage. Greenwood’s wide-body Corvettes were so reinforced many asked, “Is there still a Corvette in there?” But for street use and spirited driving, the Duntov chassis served the Corvette well until 1982. Lets look at the chassis’ basics to see why it lasted so long

The genius of Duntov’s chassis was how much lower the center of gravity was. Chevrolet engineer Maurice Olley was a production car chassis and suspension expert when he designed the C1 chassis. As a racing expert, Duntov knew he had to get the center of gravity much lower. The C1’s chassis had a parameter frame with x-bracing in the center for rigidity. The car’s occupants sat on top of the frame. Everything measured from there; the cowl height, engine height, and everything else.

Duntov’s design eliminated the x-brace so that the occupants could be placed down inside the frame, dramatically lowering every data point from there. For rigidity the new frame had five crossmembers. Duntov then mounted the engine and transmission as low and as far back as possible and routed the exhaust pipes through holes in the second frame crossmember. The passenger compartment was pushed back as far as possible and the spare tire was mounted below the back of the frame and under the fuel tank.

The lowering of the engine/transmission and passenger compartment lowered the center-of-gravity from 19.8-inches to 16.5-inches. Moving major components as far back as possible in the shorter 98-inch wheelbase created a front/rear weight distribution of 47/53-percent. The engine centerline was offset 1-inch towards the passenger side because passenger footwell requirements were less than the driver’s. The extra offset reduced the transmission tunnel width and allowed the crankshaft and rear axle pinion to be on the same centerline. Ground clearance was just five-inches.

The build of the frame used boxed longitudinal sides with five crossmembers that were designed to suit the needs of styling. The new frame actually received computer analysis to determine the thickness needed for the parameters of the overall car. The front crossmember was welded to the sides and not bolted-on like the C1 chassis. The new frame with mounting brackets weighed 260-pounds, the same as the C1’s frame, but torsion rigidity increased from 1,587 lb/ft to 2,374 lb/ft per degree.

The C2/C3 suspension was a parts-bin marvel, although it didn’t seem that way. Duntov wanted an independent rear suspension and was immediately told, “No! It’s too expensive.” To get around this, Duntov used almost 60 full-size passenger car front suspension parts, including pressed-steel wishbones and ball-jointed spindles, and just rearranged them. The parts had already been engineered and proven, thus saving production cost. With a 9-degree slope, the wishbones gave an anti-dive reaction upon heavy braking. Then the inner pivot points were lowered to raise the roll-center to 3.25-inches above the ground. A recirculating-ball steering unit was placed behind the suspension and used a hydraulic damper to reduce kickback. All of these changes were very apparent when combined with the right shocks and anti-roll bars when the cars were first driven and tested. The money saved was more than what went into the rear suspension.

The independent rear suspension started with the differential pumpkin bolted to the 4th crossmember with the driveshaft as a device to control forward thrust from the wheels. Axle half-shafts with universal joints are on each side of the differential. Steel box-section control-arms carry the outer half-shafts and attach to the rear frame kickup assembly. Shims at the forward pivot-points are used to adjust toe-in alignment. Strut rods attach to the strut-rod bracket bolted below the differential and connect to the rear spindle support on the control-arms. The nine-leaf transverse spring with polyethylene liners between each leaf to reduce noise, mounts under the differential and is sprung against the rear portion of the control arm with long bolts. Duntov’s proposal to use a transverse leaf spring was not well received by Chevrolet chief engineer, Harry Barr, but no one could come up with a better plan.

For its time, Duntov’s chassis worked very well, but I’m sure that no one imagined it would be used for 20 years. The design proved to be easy to update. Disc brakes were in development when the Sting Ray came out and arrived on the 1965 model. When the new Mark IV became available in 1965 the suspension got stiffer front springs and larger diameter front and rear stabilizer bars. The new chassis was totally adaptable and could be made near-battle-ready with suspension component changes. During the 20-years of Duntov’s chassis, Racer Kits included; the 1963 Z06, 1967-1969 L88, 1970-1972 LT-1 small-block ZR1, and the 1971 big-block ZR-2. And from 1974-1982 there was the FE7 Gymkhana Suspension for spirited street driving. On the street, Duntov’s chassis could easily handle the 327 Fuelie to the LS6 454.

In the ‘70s chassis changes were made to conform to tightening regulations. Starting in 1973 the chassis had to handle the new 5-mph crash bumpers and steel side-door guard beams. In 1975 catalytic converters helped reduce emissions, but cloaked engines. A steel underbelly had to added to the chassis as a heat shield against the very hot converters. 1980 saw a big weight reduction from 3,503-pounds to 3,336-pounds thanks to an aluminum differential, lighter roof panels, thinner material on the hood and doors, and the use of the aluminum L84 intake manifold on the standard engine. The following year, a fiberglass-composite rear leaf spring helped shed 29-pounds. Early ‘80s Corvettes don’t get much respect because their restricted engines, but their drivetrain and suspension was as good as ever. An early ‘80s Corvette with a classic SBC crate engine would make for a stout performer.

Yes, Duntov’s chassis looks crude by today’s standards. But Corvette development is always empirical. If it weren’t for the C2/C3 chassis, there never would have been a C4 chassis, and so it goes. – Scott

Corvette Chassis History, Pt 1 – C1 Chassis – HERE

Corvette Chassis History, Pt 2 – C2/C3 Chassis – HERE

Corvette Chassis History, Pt 3 – C4 Chassis – HERE

Corvette Chassis History, Pt 4 – C5 Chassis – HERE

Corvette Chassis History, Pt 5 – C6 Chassis – HERE

Corvette Chassis History, Pt 6 – C7 Chassis – HERE


 

Founding Fathers, Pt 2 of 6 – Ed Cole, the Corvette’s Godfather, Pt 2 of 6

Ed Cole was the Corvette’s Corporate Angel

 

Dateline: 10.2.18 (All images GM Archives) The Corvette is arguably the greatest enigma in Detroit history. Every car line has to carry its own sales weight. In 1957 6,339 Corvettes were sold, the same year, Ford sold 21,380 Thunderbirds. Corvette sales didn’t surpass that figure until 1963 when 21,513 Corvettes sold. How did the Corvette survive? The Times and Angels.

It was the Wild West days when William Durant founded General Motors on September 16, 1908. By 1910 Durant lost control of General Motors to a bankers’ trust. In 1912 Durant started Chevrolet, secretly bought back controlling shares of General Motors, reorganized in 1916 as “General Motors Corporation”, only to lose control again in 1918.

Successful industrialist Alfred P. Sloan, became vice president of GM in 1918, then president 1923, and brought order and structure to the chaotic company. Sloan created autonomous operating divisions, centralized policies, planning, annual model changes, platform engineering, and emphasized “styling.” Sloan hired Harley Earl specifically to “style” GM cars. Eventually, GM owned 43-percent of all car sales! By 1955 GM sold over 5 million vehicles and was the first corporation to post $1 Billion dollars profit!

Ed Cole was born on September 17, 1909 and grew up on his family’s dairy farm. As a kid, Ed designed, built, and sold radio sets and when he was old enough, the natural mechanic started working at an auto parts supply store and building hot rods. For a time, Ed thought he wanted to be a lawyer, but that “car thing” got in the way.

In 1926 GM bought the Flint Institute of Technology and renamed it, “General Motors Institute”, focusing on creating industry and business leaders through a co-op program, teaching all aspects of automobile manufacturing. Cole enrolled in 1930 and was so bright that by 1933, without finishing his GMI education, he was hired by Cadillac’s engineering department. During WW-II Ed became the chief design engineer on GM’s light tanks and combat vehicles program. In 1946 Cole was promoted to chief engineer at Cadillac and was the lead engineer on the groundbreaking, 1949 Cadillac 331 OHV high-compression, high-revving engine. Ed Cole was the “go-to” guy in GM engineering, with great things ahead of him.

There was a tremendous economic boom after WW-II thanks to pent up consumer demands after the long depression and war, but by the early 1950s a slowdown was in the making. A month after the Corvette made its debut at the New York Motorama; Harlow H. Curtice became the President of GM and understood that to make money, you have to spend money. In February 1954 Curtice announced a $1 Billion dollar plant and facilities expansion plan. Ford announced their own $1 Billion dollar capital expenditure and Chrysler committed $500 Million for expansion. Curtice doubled down with another $1 Billion and third triage of $1 Billion in 1956! Time Magazine voted Curtice “Man of the Year” for 1956. Curtice said, “General Motors must always lead.” GM was the largest corporation in the world and Ed Cole’s star was rising.

With the success of the Cadillac 331 engine, Cole was in a prime position. In 1952 Chevrolet general manager Tom Keating promoted Ed to Chevrolet’s chief engineer. Cole’s major assignment was the replacement for the 23-year-old Chevy Stovebolt Six. A V8 project was in the works, but Cole hated it and started from scratch, instructing his team that the engine should be compact, lightweight, and powerful. By the fall of 1954, the new 265 V8 was ready for 1955 Chevrolet cars, including the Corvette. No one dreamed the basic design would still be produced over 60 years later. The next step in Cole’s career was Chevrolet general manager in 1956.

In 1952/1953 a 43-year-old Russian engineer seeking employment named Zora Arkus-Duntov sent letters to Studebaker, Chrysler, Lincoln-Mercury, Ford, and General Motors, explaining his background in engineering and racing. Duntov was told that he’d find better opportunities with smaller companies, because big car companies make bread-and-butter vehicles, and don’t have much need for his skills. Zora wrote two letters directly to Chevrolet engineering chief, Ed Cole. In November 1952 Cole personally responded with, “… if you are ever in Detroit, let me know.” Duntov wasn’t happy, at least is wasn’t, “Thanks, but no thanks.”

As providence would have it, Zora went to the GM Motorama at the Waldorf Astoria Hotel and “fell in love” with Harley Earl’s EX-122 “Corvette” concept car. Years later Duntov said, “… I thought it was the most beautiful car I had ever seen…” Just before the event, Maurice Olley, Ed Cole’s chassis and suspension man, was given Duntov’s first letter to respond to. On January 5, 1953 Olley wrote to Duntov, “If you are still available, and would consider employment with Chevrolet Engineering, we can arrange an interview.” After numerous letters and an interview in March with Cole and Olley, Duntov was offered a job as an assistant staff engineer, with a salary of $14,000. On May 1, 1953, Duntov was “let in the door” and things would never be the same.

Ed Cole’s motto was, “Kick the hell out of the establishment!”. Cole also hired Frank Winchell and three-time Indy 500 winner and engineer, Mauri Rose. Duntov and Rose hit it off great. Their boss, Maurice Olley, was a quite Englishman who did not like outbursts of enthusiasm; such as whistling. Rose could be abrasive and Duntov was outgoing and gregarious. It didn’t take long for Duntov and Olley to start chaffing. The GM blue/gray suit world was a very different from Zora’s European continental culture. The culture clash was shocking to Duntov.

Olley did not like Zora’s “Let’s try this!” style of engineering, he wanted calculations. Soon, Olley suggested Duntov might consider employment somewhere else. The final straw came when Duntov told Olley he was off to the 24 Hours of Le Mans drive for Allard. Olley said, “No!” so Duntov went over his head to Cole, who wasn’t much happier. Ed explained that Maurice was retiring soon and Zora was in good position to fill Olley’s place. When Zora explained that the Allards used Cadillac engines and engineers for assistance, Cole grudgingly agreed, but Duntov’s junket would be without pay. Zora was so put off, he bought a one-way ticket, intending to not return, and send for Elfi later! I’m sure that Ed Cole’s colleagues were telling him, “Ed, he’s all yours!” Duntov would be both “angel and devil” for Cole for the rest of his career at GM.

Although Cole was a corporate man, in his heart he was a car guy, and knew that the new 265 Chevy engine would be hot. Cole decided that two 1956 Chevy 210s should run the Pikes Peak Hill Climb with Duntov as part of the team and driver. The project was very successful with the cars breaking records. At the celebration party, Duntov proclaimed, “We ought to introduce the 1957 Corvette in a spectacular manor… lets show how fast the car will go!” Cole said, “Sure! How fast?” Duntov answered, “150-miles-per-hour!” Cole responded, “Yea, we should do that.” Duntov, being from another culture, thought Cole was serious!

Back at work, Duntov told his team, “Ed Cole said we should make a 150-mph Corvette.” So, the team set about the task. After some impressive performances with a heavily-modified mule 1954 Corvette with a 265 engine using a Duntov cam and aero tricks of the day, a team of three Corvettes went to the 1956 Daytona Beach Speed Trials. With John Fitch, Betty Skelton and Duntov driving, records were broken and the publicity was great. Cole was so thrilled; he proposed a three-car team to race at Sebring. Shockingly, Duntov told Cole that he wasn’t interesting in racing streetcars, so Cole put racer and engineer John Fitch in charge of the four-car Sebring effort. Duntov couldn’t resist a racing experience and joined the group of Chevrolet engineers. The Corvette took two class wins and Chevrolet ran their famous “Real McCoy” ads.

Later in 1956, Duntov heard that Harley Earl wanted to take a D-Type Jaguar, make a new “Corvette” body, and drop in a Corvette engine. This might have been a ploy, but Duntov said, No way!” Thus began the Corvette SS Racer project. Despite an embarrassing Sebring debut, Duntov was confident he could get the car ready for a three-car team for the 24 Hours of Le Mans. Unfortunately, GM chose to enforce the 1957 AMA Racing Ban. Not even Ed Cole could help.

The best Cole could do was to put Duntov and Mauri Rose in charge of a new “Off Road” parts program. Duntov handled the engineering and Rose worked with racers to field test the parts. This was the beginning of the Duntov “Racer Kit” series of options for Corvette customers. Cole’s idea birthed legends, including; 1957 RPO 684, 1963 RPO Z06, 1967 RPO L88, 1970 RPO ZR1, and many more. Ed Cole went on to become group vice president in 1961, executive vice president in 1965, and GM’s president in 1967.

Cole faced mandatory retirement from GM in 1974 at the age of 65. He immediately went to Checker Motors Corporation (Checker Cabs) and became chairman and CEO and was also chairman of International Huskey. Cole was an avid flier and a pilot. On May 2, 1977 Cole was tragically killed flying his private twin-engine Beagle B.206 Series 2 plane near Kalamazoo, Michigan.

 

 

Image; National Corvette Museum

1998 the National Corvette Museum launched there Hall of Fame. Ed Cole was one of the six men inducted that also included; Harley Earl, Zora Arkus-Duntov, Bill Mitchell, Joe Pike, and Larry Shinoda. – Scott

Engine History Made! 100,000,000 Small-Block Chevy Engines, and Counting!

Dateline: 8.19.11
Chevrolet announces the 100-millionth Small-Block Chevy engine to be built and installed in a ’12 Corvette in Fall 2011

Former chief of Chevrolet engineering and president of General Motors, Ed Cole.

This week Chevrolet announced that the 100-millionth Small-block Chevy engine will be built sometime in Fall 2011 and will most likely be installed in a 2012 Corvette! So three cheers to Chevrolet.

Hip, hip, HOORAY!
Hip, hip, HOORAY!
Hip, hip, HOORAY!

Although the small-block Chevy engine was designed to be an efficient passenger car engine, the design’s simplicity and durability has been providing Chevy fans with some of the fiercest engines ever. SBCs have powered just about every kind of race car from Indy and Le Mans, to drag strips and dirt tracks all over America.

Which SBC will be the magic 100 millionth engine has not yet been announced. It could be the mighty 430-horsepower LS3 engine used as the base engine for the Corvette, or possibly the most powerful production engine ever built in Detroit history, the 638-horsepower supercharged LS9 that powers the C6 ZR1 Corvette rocket ship. I’m sure that Chevrolet will make a BIG media splash about this car.

Enjoy our Small-Block Chevy engine gallery.

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The man credited with designing and developing the SBC was former General Motors president, Ed Cole. As a youngster Cole liked to tinker with radio sets and was briefly a field rep for a tractor manufacturer before enrolling in the General Motors Institute where he got his degree in engineering. In 1949, along with GM’s Harry Barr, Cole developed the acclaimed 1949 Cadillac OHV V8 engine. By 1952 Cole was promoted to chief of engineering for Chevrolet. His first major project was the design and development of the replacement for Chevrolet’s tired, old, Stovebolt-Six engine. The finished engine was essentially a simplified, smaller version of the Cadillac OHV engine he’s helped design in ‘49.

When nested between the front fenders of the new ‘55 Chevy, the 265-cubic-inch, 162-horsepower engine looked, well, tiny. It probably only took a few weeks for hot rodders to realize that there was a ton of red meat in the little lightweight engine. The new small-block Chevy quickly developed the nick name “Mouse Motor.” Within a few years, the new SBC completely changed hot rodding and racing. It was, “good-bye Flathead Ford” and “Hello Small-Block Chevy.” Continue reading “Engine History Made! 100,000,000 Small-Block Chevy Engines, and Counting!”