Doomed: Chevy Cosworth Vega (1975-1976)

Editor’s Note: This post is an excerpt from Eric Peters’ forthcoming book Doomed!

It worked better for Pontiac.

The now-iconic black and gold paint scheme made famous by the ’77 Trans-Am that Burt Reynolds drove into automotive history in Smokey and the Bandit failed to work the same magic on the first GM production car that got the same look—the ’75 Cosworth Vega.

Probably because under the striking paint job, it was still a Vega, the car that almost doomed General Motors due to its oil-thirsty engine that burned almost as much lubricant as gasoline due to ill-conceived (or rather, ill-manufactured) 2.3-liter aluminum block engines without cylinder liners.

A new casting process was meant to eliminate the need for liners, reducing manufacturing costs but ended up costing Vega owners plenty.

The “tallest, smallest” engine (so named for its long stroke) was prone to horrendous vibration and running hot, due to its Siamese cylinder bores, which made it more vulnerable to overheating, both deficiencies resulting in sealing problems between the aluminum block and the cast iron cylinder head.

Differential heating would warp the dissimilar surfaces; coolant would then leak into the cylinders, scuffing the “diamond cast” machine-finished surface, which quickly resulted in catastrophic wear and horrendous oil consumption.

GM tried to mask the vibration problem by fitting the Vega with extra-flexible rubber engine mounts that allowed the engine to dance under the hood without transmitting the movement to the car’s occupants in the cabin.

But the underlying problems remained including a just-barely-adequate cooling system that became inadequate when it ran even slightly low, which would happen when it boiled over. Then cue the overheating and then sealing and then cylinder scuffing and then oil-burning—plus shoddy valve stem seals and a backfire-tending carburetor that sometimes triggered fires downstream in the exhaust system. It made the Pinto seem like a Rolex.

But wait, there’s more!

Credit: Greg Gjerdingen

Early Vegas also were afflicted with an idle-stop solenoid bracket that had a tendency to work loose, jamming the throttle open. Chevy advised owners to “turn off the ignition and apply the brakes” in the event this happened.

The Vega’s problems weren’t just under the hood, either. The rear axle was prone to inadvertent disassembly while the car was moving; the “electrophoretic” anti-corrosion treatment dip applied to the body at the factory was not applied uniformly, resulting in early rusting of untreated areas, especially in the cowl area and around the front fenders.

Routine alignments could not be performed because of seized fittings that necessitated cutting off the affected components with an acetylene torch and replacing them before adjusting them. The area around the base of the car’s windshield often rusted out so severely that the windshield was no longer securely held in place and would fall into the car.

Six of seven early Vegas, which first became available in 1970 as ’71 models, were recalled for one reason or another and often several. GM had to replace more engines under warranty almost as quickly as the factory engines went through a case of oil.

John DeLorean, who oversaw the early years of the Vega’s development as Chevy’s general manager, blamed rushed development and rushed assembly for most of the car’s (and buyers’) woes. The Vega was hashed together over the course of just 24 months without, according to DeLorean, adequate time to fully test the essential soundness of the design.

One test mule reportedly came apart literally while being evaluated on GM’s proving grounds in Michigan. But instead of halting the production schedule to find out why this happened and fix it, management greenlit production. The company was reportedly desperate to get the car into showrooms for the 1971 model year, no matter what.

And then “what” happened.

“While I was convinced that we were doing our best with the car that was given to us, I was called upon by the corporation to tout the car far beyond my personal convictions about it,” DeLorean told J. Patrick Wright, author of On a Clear Day You Can See General Motors, which was published in 1979. By then, DeLorean was working on his own on what would prove to be another doomed car, the infamous stainless steel-bodied, gull winged DeLorean DMC coupe of Back to the Future movie fame.

When Vega production began in 1970, it was on a hurried-up schedule, too. The Lordstown, Ohio assembly plant was initially chucking out 100 new Vegas per hour, twice the usual volume. Much of the line was automated, using Unimate industrial robots to perform 95 percent of the 3,900 welds necessary to put the bodies together. But the work that still had to be done by hand was double-speeded such that a task that had previously been allotted 1 minute to perform was now supposed to be done in 36 seconds.

Predictably, build quality was spotty.

As was paint quality, which was below the usual standard because the spray booths were expected to finish cars much faster than they had been designed to handle, leading to runs and sags and orange peeling paint jobs that had to be redone either at the factory or the dealership.

Though initially well-received, the Vega quickly became GM’s biggest and most publicly embarrassing fail since the first-generation Corvair, a car that was far less lemony in terms of its basic soundness. Unlike the Vega, the Corvair wasn’t poorly built relative to others cars of its time and its bad reputation for evil handling wasn’t so much the car’s fault as the fault of drivers who failed to heed the factory tire inflation recommendations and then drove the car beyond their capabilities.

Cars magazine summed up the situation with the Vega as follows:

“Tests which should have been done at the proving grounds were performed by customers, necessitating numerous piecemeal fixes by dealers. Chevrolet’s ‘bright star’ received an enduring black eye despite a continuing development program which eventually alleviated most of these initial shortcomings.”

Credit: Vegavairbob

That sets the scene for the Cosworth Vega, which, so it was hoped, would rehab the Vega’s by-then horrendous reputation by showcasing technology that not even the Corvette was available with such as electronic port fuel injection. The Cosworth Vega was the first GM production car to come standard with it.

Also the black and gold paint scheme with matching gold-anodized alloy wheels (years before the Trans-Am would offer such) and “engine-turned” dash facing, styling touches that would be iconic a couple of years later when they were used to create the “Bandit” Trans-Am.

The Cosworth Vega also had things no “Bandit” Trans-Am ever got, including 9,500 RPM capability (with a 7,000 RPM redline for the production engine) and a higher (122 MPH) top speed. The “Bandit” Trans-Am’s 400 cubic inch V8 engine redlined just over 5,000 RPM and its top speed was gearing-limited to about 118 MPH.

But the “Bandit” was a Trans-Am and didn’t have the legacy problems that beset the Cosworth Vega before the first one was offered for sale in ’75. Still, there is no denying it was a revolutionary car for its time and had GM built a Vega that was more like the Cosworth Vega back in ’71, the stars might have aligned better for this ill-fated attempt to repair what was probably already beyond repair.

Development work actually began shortly after the ’71 launch of the regular Vega. DeLorean sent engineer Calvin Wade to England, to commune with British engineers at Cosworth, whose specialty was (and is) the development of high-airflow/high-revving engines, chiefly for F1 racing.

GM would collaborate with Cosworth to develop a new high-performance street engine based on race car engine design, in particular the dual overhead cam cylinder head bolted to the standard Vega engine block. This time, there would be no aluminum block/iron head mismatch and built-in sealing problems. While the block was more or less stock, it was fitted with high-strength/lightweight forged aluminum pistons to reduce the mass of the reciprocating assembly, so as to enhance the high-RPM capability. The crank was also upgraded to heat-treated forged (rather than cast) steel while the Cosworth-designed head got sintered iron valve seats.

A beautiful stainless steel header snaked backward toward the cowl, where it fed into (initially) a dual outlet exhaust. The engine with its aluminum rather than cast iron cylinder head shaved some 60 pounds off the Vega’s nose, resulting in a curb weight of just 2,760 pounds.

The car’s serious demeanor was enhanced by the absence of amenities such as air conditioning and power steering, but the real eye-popper was the Bendix port-fuel injection (PFI) system that fed the mighty-mouse engine. This was a leap ahead of the throttle body (TBI) systems that began to gradually replace mechanical carburetors beginning in the early-mid 1980s. TBI systems were functionally very similar to carburetors in that they used a single throttle body, which sprayed fuel into a common intake plenum, or manifold, the fuel and air then sucked into the engine’s intake ports. PFI uses an individual injector for each of the engine’s cylinders; this allows much more precise tailoring of the amount of fuel being injected, a boon for both power and economy as well as lower emissions, which GM and other car companies were faced with having to deal with in a big way by 1975.

To get by the EPA’s new strictures, almost every new car made for ’75 had to have a catalytic converter (essentially a chemical exhaust scrubber) and the still-carburetor-fed engines of the time had to be tuned to run very lean, which made them run not very well. It also had a crippling effect on horsepower and performance.

The ’77 “Bandit” Trans-Am looked fast but its 6.6-liter 400 cubic inch V8 only summoned 200 horsepower, which wasn’t enough to lug the 3,800 pound Trans-Am to 60 more quickly than about 7 seconds.

Thanks to its free-flowing Cosworth head, its Bendix EFI system and not having to lug around 3,800 pounds, the Cosworth Vega was nearly as quick to 60 and slightly faster on top. Its freer-breathing, much-freer-revving, shorter-stroke 122 cubic inch engine may have only developed 110 horsepower in production tune but development mules were making 170-260 using the stock block and even 110 hp was proportionately impressive for an engine less than half the size of the Trans-Am’s 400 cubic inch engine.

But it was also an expensive engine, accounting for much of the cost of the car, which at $5,918 asking MSRP, was nearly the same asking price of a new Corvette.

The Bendix EFI system included multiple sensors, in addition to multiple injectors and a computer—the ECU, or Electronic Control Unit—to run the works. It was very elaborate, very expensive tech for 1975.

And it was hard to convince people to pay for it in a Vega, rather than a Corvette.

Even so, the car press loved it. Motor Trend enthused that “it goes like the proverbial bat out of Carlsburg Caverns,” particularly praising the engine’s 7,000 RPM capability. Car and Driver described it as a “taut-muscled GT coupe to devastate the smugness of BMW 2002tii’s and Alfa GTVs.”

But the price was just too high and the reputation’s stink just couldn’t be dissipated.

After a poor reception in its debut year, Chevy tried further enticements, such as a new standard five-speed (overdrive) manual transmission, replacing the ’75’s four speed without OD (no automatic was ever offered due to the engine’s high-RPM, race-bred character), and the availability of a SkyRoof and 8-track tape player/AM/FM stereo combo.

AC, however, was still off the table. Also power brakes and windows. It was as close to a factory racer as you could buy that year assuming you could afford to buy it. Chevy even touted its cost: One Vega for the price of two.

It wasn’t the ticket for sales success.

Over the course of its two-year production life, just 3,508 cars were sold, falling well shy of the initially intended 4,000 examples Chevy had planned to sell. GM would not offer EFI in a production car for almost another decade and then in the Corvette, in the form of what was marketed as Tuned Port Injection (TPI) beginning in 1984. By then, people were willing to pay for it, provided it was in a Corvette.

The tragic thing about the Cosworth is that it was a good-looking, good-handling, extremely sophisticated car that probably would have done well if it hadn’t been a Vega.

And the Vega didn’t have to be the Hindenburg-level disaster it turned out to be for all concerned, including GM, which to this day hasn’t recovered from the damage to its reputation incurred by the slipshod design and rushed production of the ’71 Vega.

As of 2021, General Motors (all of it) sells fewer cars than Chevrolet, by itself, sold in 1970. Largely because it drove away half of its market by trying to sell people cars like the early Vegas.

Cosworth Vega Trivia

  • Cosworth Vega engines were hand-assembled on a special line by teams of two to three master technicians at the Tonowanda engine assembly plant in New York. A number of completed engines (perhaps as many as 500) were ultimately scrapped after the car was cancelled.
  • GM designer Bill Mitchell, who styled the 1970 Camaro, was heavily involved the styling of the original 1971 Vega, which borrows heavily from the Camaro’s overall themes.
  • Race versions of the Cosworth engines had dry sump oiling systems, higher compression ratios and Lucas mechanical fuel injection but were otherwise very similar to the production street car versions.
  • During pre-production testing, the Cosworth engine held together when spun to 9,400 RPM and subjected to 500 hours of operation at full load.
  • While first-year Cosworth Vegas are all finished with black and gold exteriors, second-year Cosworths were available in a variety of palettes, including Antique White, Dark Green Metallic, Buckskin, Firethorn Red Metallic, Medium Orange, Medium Saddle Metallic, and Dark Blue Metallic. The ’76 models also had differently-designed tail lights and grill as well as the five-speed overdrive manual transmission that was not offered in ’75. These last year Cosworths are also the rarest of the breed, with 1,447 examples made vs. 2,061 in ’75.
  • Both years came with serialized plaques, the gold-faced engine-turned dash with full gauges (including an 8,000 RPM tachometer) and Camaro-style steering wheel with special badging.
  • The last Cosworth Vega delivered to a dealer was painted Medium Saddle Metallic and delivered to a Cleveland, Ohio dealership.
  • The very first Cosworth (serial number 0001) is currently part of the GM Heritage Collection and occasionally displayed. It has a see-through Plexiglas hood to showcase the Cosworth engine underneath.
  • The Vega, itself, survived for one more year, but was cancelled after the 1977 model year. Its replacement, the Monza, was heavily based on the Vega but restyled to avoid any comparisons. It was cancelled after the 1980 model year.

Eric Peters lives in Virginia and enjoys driving cars and motorcycles. In the past, Eric worked as a car journalist for many prominent mainstream media outlets. Currently, he focuses his time writing auto history books, reviewing cars, and blogging about cars+ for his website EricPetersAutos.com.

Editor’s Note: The opinions expressed in this article are those of the author.

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