Tag: GM

GM TH700R-4 transmission – Jim O’Clair @Hemmings

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Another low-buck automatic conversion that could very well pay for itself

Several months ago we highlighted the Turbo Hydra-Matic 200-4R transmission as an automatic overdrive transmission for the economy-minded. The addition of an overdrive gear to any three-speed transmission, be it an automatic or manual shift, can improve fuel mileage and help decrease the wear and tear on your engine.

This month we will discuss the big brother to the TH200-4R referred to by General Motors as either the TH700R-4 or their later designation for it, which was the 4L60 transmission. Although some transmission installers feel that the low first-gear ratio and high second-gear ratio do not make the TH700R-4 the best racing transmission, there are quite a few adaptations you can perform to make it a race-ready drivetrain component. Weighing 184 lbs. this transmission can easily handle power torque ratings up to 650-lbs.ft. of torque, while propelling as much as 8,500 lbs. of payload down the pavement. This makes the TH700R-4 a prime candidate for a swap into any GM rear-wheel driver as a replacement for a TH350, Powerglide, TH400, or TH200-4R.

The TH700R-4 was the first overdrive automatic transmission used in GM cars and trucks in 1982, designated as a Hydra-Matic MD-8 transmission according to GM’s RPO codes. The quickest way to identify one of these units in a vehicle is by the square 16-bolt oil pan. The governor and speedometer drive are both located on the driver’s side of the transmission, the sleeve for the speedometer gear can be found in the tailhousing of the unit. TH700R-4 transmissions use a lock-up torque converter, and they use an electric control solenoid to operate the lock-up function. The electrical connector for this solenoid connector is also on the driver’s side of the transmission case.

Initially, the TH700R-4 came with a 27-spline input shaft from 1982-1984. Later production units were equipped with a 30-spline input shaft. Although the later 30-spline version is more desirable, both units can be interchanged if a torque converter with the proper spline count is also used. For the most part, you will find TH700R-4 models using the standard 153-tooth GM small-block flexplate; however, there are 168-tooth Chevy big-block and 166-tooth Pontiac flexplates available in the aftermarket. A detent or TV cable controlled the passing gearshifts. Several different detent cables were used depending on the vehicle the donor transmission came from. Later versions of this transmission, referred to as the 4L60E (1993 and up), used an additional electric kickdown solenoid to engage the passing gear; however, for this article we will be focusing on the earlier TH700R-4 and the 1990-’93 4L60 units.

TH700R-4/4L60 transmission shift ratios are: First, 3.06:1; Second, 1.625:1; Third, 1.00:1; OD, 0.69:1; Reverse, 2.29:1.

Both the TH700R-4 and the 4L60 versions have an overall length of 30-3/4 inches except in the Corvettes, which measure 29-7/8 inches overall. All other important dimensions such as bellhousing bolt circle and location of the transmission mount are listed in the parts locator section of our website at http://www.hemmings.com/parts-locator/transmissions.html.

You can find a donor transmission from one of these General Motors vehicles:

o 1984-’91 Buick Electra, LeSabre and Estate Wagon

o 1991-’92 Buick Roadmaster

o 1990-’92 Cadillac Fleetwood Brougham

o 1982-’92 Chevrolet Impala and Caprice

o 1983-’93 Chevrolet Camaro and Pontiac Firebird

o 1983 Chevelle

o 1982-’92 Corvette

o 1985-’91 Chevy Astro Van

o 1982-’93 S-10, T-10 and Sonoma small pickups and Blazers

o 1991 R and V series Suburbans up to 3/4 ton

o 1982-’93 C and K series pickups up to 3/4 ton

o 1982-’93 G series vans up to 3/4 ton and full-size Blazers

o 1991-’92 Olds Custom Cruiser station wagon

o 1991-’93 Olds Bravada

o 1986-’88 Pontiac Bonneville

o 1987-’88 Pontiac Grand Prix

o 1983-’86 Pontiac Parisienne

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How many GM EV1s still exist, and do any of them still run? – Daniel Strohl @Hemmings

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Every now and then, another forlorn dust-covered and inoperable GM EV1 makes the rounds on automotive websites and social media. Typically, it’s heralded as the last of its kind or a major discovery, and some people even make attempts to conceal the cars’ locations as if they were archaeological dig sites that needed to be protected from grave robbers and treasure plunderers. However, the reality is that many of the remaining EV1s not in GM’s hands are on public display, have been well publicized, or have become open secrets among generations of engineering graduates over the last 20 years or so. Amazingly, nobody seems to have made an attempt to run down the current whereabouts of all the GM EV1s still in existence, so let’s do so here.

First, a little background. GM built 1,117 EV1s for public release: 660 in 1997 and another 457 in 1999. None were sold to the general public; all were made available via a lease program to customers in California, Arizona, and Georgia. When those leases came to an end starting in 2003, GM took back every single EV1 and decreed that the cars would be removed from the road permanently. The subsequent crushing of many of the EV1s triggered protests from many of those lessees and others who felt that the car and its advanced technology deserved to remain on the road.

That said, GM didn’t destroy every EV1. Similar to what Chrysler did with the Turbine cars, the company donated some EV1s to museums and some to colleges and universities for their engineering students to pick apart and study. In all but one instance, the donated cars were made inoperable, and as part of the deal, GM mandated that the vehicles not be returned to the road.

But how many exactly escaped GM’s crusher? Sources generally claim 40, but that’s not a hard and fast number, and occasionally somebody will claim less—either 15 or 20. One EV1 fan claims there are as many as 180 EV1s, though some of those may be concept, demonstration, or show cars still owned by GM, and some of that number may have been crushed by GM. According to EV collector Steve Hawkins of the Beata collection, 37 total still exist, with nine of those currently in private hands, though as he noted, owners of the cars still prefer to remain secretive and a tight-knit group. “Just in the last couple of years we discovered another complete original car, but the contacts, trust and relationships to get that information developed over a decade of what we call ‘social engineering,'” Hawkins said. “There is another EV1 we are trying to identify now that will likely take years to verify. Our mission is to help every remaining chassis survive for history and education’s sake.”

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Livonia, There’s Something About You – Andrew Miles @Driven to Write

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Four feral felines from Buick.

*1953 Buick Wildcat I. Image: oldconceptcars*

Buick have form when it comes to concept vehicles, especially since a certain Harley Earl began such pioneering strides with 1938’s seminal Y-Job, which helped to define the Tri-shield’s design credentials. In 1949, GM’s Autorama car show was held at the Astoria Hotel in New York to promote new concept designs to a public desperate to embrace the future. Years 1953-1961 saw Motorama become a travelling show.

For 1953, Buick introduced the Wildcat, a low slung two seat convertible with a raked back windshield and party piece hood. Hydraulically operated, the roof disappeared beneath the rear panel at the flick of a switch. Other components employing pressurised oil included seat and window movements. The bodywork was fibreglass and the hub caps Roto-Static, where the centre is stationary and the wheels rotate, à la Rolls-Royce. As with many of these creations, public reaction was favourable but in essence, the Wildcat only really previewed the new for ‘54 Buick front end.

Wildcat II unveiled in 1954, based on the Chevrolet Corvette with power derived from a supercharged V8. A clamshell hood covered this powerplant, hiding the wheels which did away with conventional fenders. The chrome bumpers contained floating driving lamps which again, Joe Public applauded but with Corvette sales struggling at the time, there was no incentive to diversify into Wildcats.

Earl’s final attempt arrived the following year with something looking considerably more production-ready – you guessed it, Wildcat III. However, this new feline seated four, maintaining a grand feeling with a 250bhp V8 but for a feline, this seemed somewhat bug-eyed. Publicity shots saw designers Ned Nickles and Harley Earl grinning by the car’s side, but apart from a smattering of forthcoming styling cues, Wildcat III was another dead end. Earl’s retirement saw the name hibernate for thirty years.

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Pick of the Day: Different twist on the hot rod – Larry Edsall @ClassicCars.com

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With this being the 90th anniversary of the classic ’32 Ford hot rod, look for prices of those vehicles to get a bump as celebrations are held at car shows across the country.

It turns out, however, that you can have a hot rod without going to the extremes of the ’32 Ford. The Pick of the Day is a hot-rodded 1922 Overland, and it’s private owner in Sacramento, California, is offering it for what seems a reasonable $16,995.

Among the things making this hot rod more affordable while still quite rare is its conversion on an Overland chassis and, instead of a flathead Ford V8 or even a small-block Chevy V8, the builder opted for an inline 6-cylinder engine from General Motors.

Overland was founded in 1903 in Terre Haute, Indiana, by Claude Cox, a graduate of the local Rose Polytechnic Institute and an employee of the Standard Wheel Company. Cox relocated his automaking enterprise to Indianapolis in 1905. Three years later, Overland was purchased by John North Willys and became part of his newly renamed Willys-Overland company based in Toledo, Ohio.

For the 1922 model year, Overlands were offered in 3- or 5-passenger configurations, with roadsters, coupes and sedans each powered by a 4-cylinder engine rated at 27 horsepower.

The seller says this hot rod has steel coachwork and frame from a 1922 Overland while the GM engine is mated to a 2-speed “power-glide” transmission. The ad does not specific which GM inline 6 is used, nor does it include displacement or power rating

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Electric Hot Rods: Sacrilege, or a Glimpse of Our Future? – Terry McGean @Hemmings

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“Well, they’ve finally ruined Project X…”

“This is the worst idea I’ve ever seen executed on this car.”

“Look, they turned Project X into a golf cart.”

That last comment about the golf cart seemed to offer some insight. It stemmed from the belief floating around early in the week that the ‘57’s new drivetrain only offered one-hundred-some-odd horsepower–that wouldn’t be enough to excite anyone when mounted to a vehicle that likely weighed around 4,000 lbs with the battery packs. Without the performance, enthusiasts aren’t interested. Clean air and efficient transport might be benefits they’d look for in a commuter, but not in a hot rod. So, even when it became clear that the motor was actually good for about 340 hp, attitudes weren’t swayed much. That’s on par with a garden-variety mild performance small-block these days–no need for alternate propulsion to achieve that.

Again, it is that potential for rapid acceleration that has made the electric motor option at least mildly palatable for many enthusiasts, if not intriguing. While electric cars have existed for nearly as long as cars themselves, for most of its history, the automobile has been motivated by combustion engines, and the electric variations that cropped up sporadically through the years usually seemed like compromised oddities. As such, the tried and true combustion engine had remained essentially unchallenged from a performance standpoint.

But something changed in the 1990s, when General Motors created a concept electric car it called the Impact. It was designed from the ground up to be electric, rather than using an electric drivetrain in a modified existing car. The experiment was interesting enough to garner the attention of the California Air Resources Board, which then mandated that major auto manufacturers produce zero emissions vehicles as a stipulation of continuing to sell conventional combustion engine vehicles in California. General Motors released the EV1, the production electric car that was based heavily on the Impact, and consumers in Southern California and Arizona were allowed to lease the new cars.

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The GMC Syclone was the world’s quickest pickup | Revelations with Jason Cammisa | Ep. 13 @Hagerty

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The GMC Syclone wasn’t just quick — in its day, it was among the quickest vehicles ever tested. And that success was lingering: the Turbo Truck was, by a significant margin, the quickest pickup truck in the world for a staggering 30 years. That’s nearly twice as long as the McLaren F1 held the top-speed record.

Surprise: it also handled well, keeping up with the supercars of its day.

What’s not a surprise: the Syclone, and its SUV-bodied brother, the Typhoon, were not conceived through the regular product-planning channels at General Motors: they were dreamt up by a Real Car Guy — Kim Nielsen — and pushed through using the help of outside consultants.

To get into production quickly, before the S-15 Sonoma pickup and Jimmy SUV ended their product cycle, Nielsen worked closely with ASC/McLaren and then Production Automotive Services to develop the turbo truck. And then PAS won the contract to engineer, certify, and build the SyTy (Syclone and Typhoon.)

With just a little wheelspin off the line, the Syclone blasted from 0 to 60 mph in just 4.3 seconds, quicker than the then-brand-new C4 Corvette ZR-1 and almost as quickly as the Ferrari F40.

30 years later, there are many fast SUVs on the market, but until the 702-hp 2021 Ram TRX, there’s never again been a pickup this quick. And certainly none this good-looking: available only in black, with black trim that includes a deep air dam and (of chief importance) integrated fog lights.

Learn everything you need to know about the GMC Syclone in this entertaining episode of Revelations with Jason Cammisa.

GM’s New Pump-Gas ZZ632/1000 Crate Engine: 1,000 Naturally Aspirated Horsepower in a Box – Jeff Koch @Hemmings

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Modern rally cars fling themselves sideways around woodland courses with 400 turbocharged horsepower on tap. Today’s Indy cars make between 600 and 750 horsepower to go 230-plus mph at the 500. DTM touring cars from Germany top 600 ponies. And contemporary NASCAR racers churn out 750 horses and regularly touch 200 mph on superspeedways.

This is all context for Chevy announcing its ZZ632/1000 crate engine at SEMA, the annual automotive bacchanalia-infused trade show in Las Vegas. It’s all in the name: The engine displaces 632 cu.in. and makes 1,000 naturally aspirated horsepower (or 1004 horses, but when you’ve entered four-digit-horsepower territory, it’s probably okay to round a little). It also delivers 876 pound-feet of torque on pump gas. That’s more power than a NASCAR stocker or an Indy car has. All that in a box—and maybe between the wheel wells of your own car.

Other crate engines with 1,000 horsepower have been made available, but the ZZ632/1000 is all engine, no power-adder required. The block is shared with GM’s already-available 572-cu.in. crate engine, which includes four-bolt mains and a forged rotating assembly. For 632-cube duty, the block has been treated to a 0.040 overbore and was redesigned to fit connecting rods that are 0.375 inch longer. Those new rods are topped by pistons that, in conjunction with the new CNC-machined aluminum cylinder heads, squeeze the air-fuel mixture as 12.0:1 compression.

The RS-X Symmetrical Port heads were designed by Ron Sperry, one of his final jobs at GM after more than half a century of building hot street and racing engines for GM. Rather than the uneven port shapes of previous big-blocks, these heads feature symmetrical intake and exhaust ports so that no cylinder is “starved”; all eight chambers get an equal air/fuel mix. It’s a trick Sperry used on the Gen III small-block (i.e., the LS engines launched in the C5 Corvette). While not strictly new, it remains an effective power strategy.

The Deal That Could Have Changed History, GM tries to acquire Ford. Here’s why it didn’t happen – Larry Printz @TheDetroitBureau

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This week in automotive history, GM tries to acquire Ford. Here’s why it didn’t happen

Imagine General Motors owning Ford. It nearly happened, until it didn’t. TheDetroitBureau.com looks at what nearly happened, and why it didn’t.

William (Billy) Crapo Durant Founder of GM

William Crapo Durant — Billy to his friends — became President of the Buick Motor Co., after its founder, David Buick, left the company, along with $100,000. All was going well at Buick, and Durant soon left the office to have dinner with his daughter, Margery, when he was called to the phone. It was Benjamin Briscoe Jr., president of the Maxwell-Briscoe Co.

The conversation was recalled by Durant in notes for a never published autobiography and later recounted by Buick historian Lawrence Gustin in his book, “Billy Durant.”

“Hello, Billy, I have a most important matter to discuss with you and want you to take the first train to Chicago.”

Durant answered, “What’s the big idea, Ben?”

“Don’t ask me to explain; it’s the biggest thing in the country. There’s millions in it. Can you come?”

“Impossible, too busy, sorry,” Durant said. “But I can see you here. Why don’t you take the 10 o’clock Grand Trunk arriving at 7 o’clock tomorrow morning? I will meet you at the station and we will have breakfast together.”

Briscoe agreed, and boarded the train later that night.

A meeting begets a big idea

The next day, the two meet, with Briscoe telling Durant that a J.P. Morgan partner and Maxwell-Briscoe financier was toying with the idea of a large merger of automakers, nearly two dozen. Durant had his doubts.

The plan involved too many companies and would take too much to resolve any differences. Durant countered with another proposal, one involving fewer automakers that would sell medium-priced cars in large numbers, such as Ford, Reo, Buick and Maxwell-Briscoe.

Upon further discussion, they contacted Ransom E. Olds, who ran Reo, and Henry Ford, who agreed to meet with Briscoe and Durant at Durant’s suite in the Pontchartrain Hotel in Detroit.

Briscoe opened the meeting, stating he wanted the group to formulate a consolidation plan the could be presented to J.P. Morgan. But Ford and Olds wanted cash for their companies, at least $3 million each.

This proved to be a big hurdle. With the chances of success fading, the final straw proved to be a short item in the New York Times, stating that the first large consolidation of automakers was coming, and would be named International Motor Co. and capitalized at $25 million.

Morgan withdrew its support. The big idea was dead.

Durant carries on

Morgan may not have liked the idea, but Durant did.

Before long, he contacted the Olds Motor Works in Lansing, Michigan about consolidating Buick and Olds, with both companies owned by a holding company to be named General Motors.

Henry Ford was mired in the Selden Patent case at the time when Durant proposed the purchase of his company

Olds had fallen on hard times after the departure of their founder, Ransom Olds, several years before, and were anxious to consolidate. On Sept. 16 1908, General Motors was incorporated, starting an acquisition spree that led Durant to acquire the Albert Champion Co., the Oakland Motor Car Co., and Cadillac Automobile Co. among dozens of others.But one prize still eluded him: Ford Motor Co

At the time of Durant’s offer Ford had just introduced the moving assembly line

Durant tries again

In 1909, Durant approached Ford’s business manager James Couzens about General Motors’ interest in acquiring Ford Motor Co. Couzens said he would talk it over with Mr. Ford. At the time, Ford was fighting George Selden, a patent lawyer who was granted a patent for the automobile.

Selden formed the Association of Licensed Automobile Manufacturers and began collecting a 0.75% royalty on all cars sold. But automakers had to get a license from the ALAM. Having been refused one by the ALAM, Ford built cars anyway. Selden sued, and the case dragged on for years. Ford was still battling Selden when Durant’s offer arrived. With victory uncertain, and huge costs being incurred with the installation of the automobile industry’s first assembly line, Ford couldn’t help but be swayed by the offer.

“I had reason to believe that if we were successful, General Motors would not require any more motor car companies,” Durant writes.

Ford agreed to sell his company to General Motors for $8 million. His terms: $2 million in cash, $2 million in stock, and the remaining $4 million paid during the next three years at 5% interest. But Durant’s acquisition fee left GM short on cash. Durant turned to the National City Bank of New York to ask for a $2 million loan, even as GM’s board of directors gives Durant the authority to buy Ford on Oct. 26, 1909. But the bank was unwilling to take a risk on the fledgling industry, let alone Durant’s new company.

The answer was no.

The fallout

Ultimately, Ford would prove victorious over Selden upon appeal, and the assembly line proved a wise innovation. By the 1920s, Ford would control half the U.S. automobile market with a single vehicle, the Model T. Ultimately, through a combination of factors, GM would surpass Ford, become the top seller of automobiles in the U.S. for decades.

However, one wonders what might have been had things turned out differently in 1909.

While those same bankers later admitted they made a mistake, Durant harbored no regrets. “I never would have built up that business the way Ford did,” he recalled. “The Ford business would never have been what it is without Henry Ford, who has done more for America than any other man — more for the world.”

9 tragically flawed GM vehicles whose heroic fixes came too late – Sajeev Mehta @Hagerty

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Decades upon decades passed when General Motors could do no wrong, and the products rolling off its assembly line were proof positive of its business model’s supremacy. But nobody’s perfect, and mistakes had to be addressed to meet stockholder’s expectations. GM’s design and engineering teams made some great cars with serious potential that were packed with tragic flaws—and received heroic fixes that came right before their curtain calls. It’s all rather tragic, so here are nine examples to prove the point.

1993 Cadillac Allanté (Northstar)

You gotta give General Motors credit, because when it aims for the stars, it grabs a firehose full of ideas and shoots skyward. Take a shortened E-body coupe and turn it into a bespoke V-body, then deliver finished shells from Italy’s Pininfarina to Hamtramck via a convoy of Boeing 747s known as the “Air Bridge.” One of the biggest keys to the Allanté’s failure was the drivetrain layout (front-wheel drive does not a Mercedes SL competitor make) and the mediocre performance of Cadillac’s High Technology V-8 engines.

The lack of power was finally addressed in 1993, the Allanté’s final year, by the rocket-like thrust of Cadillac’s all-new Northstar V-8. The added grunt was competitive, but 1993 also included a heavily revised rear suspension, active dampers, and revised power-steering. As we previously mentioned, the 1993 Allanté was “finally, the internationally competitive luxury roadster its creators had envisioned … albeit six years too late.”

1988 Pontiac Fiero

One of the big problems with the Pontiac Fiero, aside from the engine fires of the early models, was the promise of sporty performance, which wasn’t realized until the last year of production. As we previously mentioned, cost-cutting sealed the Fiero’s fate well before 1988. There was simply too much parts-bin engineering: The compact X-body (Citation) front suspension was flipped 180 degrees and dropped in the back, while the front suspension was lifted from the T-body subcompact (Chevette). It’s a shame that in the Fiero’s final year the necessary suspension upgrades (new front control arms, knuckles, and an all-new tri-link rear suspension, plus a wider front track and, on WS6 models, staggered wheels) and improved brakes (four wheel vented discs) couldn’t alter the course of history. These bits were precisely what Pontiac engineers intended for the Fiero from the get-go. At least we got one year of mid-engine Pontiac Excitement.

2020 Cadillac CT6-V (Blackwing)

Hate to say it, but the Cadillac CT6 is not unlike the Cimarron before it. That’s because the last examples of Cadillac’s J-body experiment indeed improved when a 2.8-liter V-6 and five-speed manual transmission were standard equipment. Similarly, the CT6 never set the world on fire, because a flagship luxury sedan needs more swagger under the hood than a turbocharged four-cylinder could ever provide. (Yes, the CT6’s standard engine was 0.8 liters smaller than what’s on tap for a 1987 Cimarron.)

The CT6 didn’t receive a proper V-8 until the 2020 CT6-V hit the scene with the similarly star-crossed Blackwing motor. Because there is still a market for upper-crust luxury sedans (think Mercedes S-Class), the CT6 deserved an optional V-8 from the start. What happened when the CT6 got it all? Both the engine and the car unceremoniously met their maker

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Someone Owns A Twin-Engine Chevrolet Citation X-11 Mid-Engine Corvette Test Vehicle: Video – Sean Szymkowski @GMAuthority

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Robert Cope’s One-of-a-Kind X-11 research vehicle.

Thankfully, the V8 engine hasn’t met its demise quite yet. But, in the 1980s, automakers were concerned for its future. This led General Motors to chase new opportunities for the Corvette, which almost led to a mid-engine variant decades ago. Now, it seems the Corvette will finally fulfill those mid-engine dreams with the C8 Corvette.

That’s another topic for another story. This story, first reported by Jalopnik, is about some crazy man who has kept a 1985 Chevrolet Citation. But, it’s not any old Citation. This is a Citation X-11 mid-engine Corvette test mule.

That’s right. In 1985, Chevrolet created a Citation with two engines, one in the front and one in the back. Two aluminum 3.1-liter V6 engines were stuffed into the rear and front for a total of 400 hp. In regular driving, the Citation X-11 could use just the front-mounted engine to drive the front wheels. But, the driver could also turn the economy car into a beast with the flip of a switch.

In turn, that would unlock the rear engine, turning the FWD Citation into a 400 hp, all-wheel drive machine.

Hot Rod once described the Citation X-11 as so:

Imagine a GMC Syclone or Typhoon with less weight and nearly twice the power.
We like the sound of that. Have a look at the video of the Citation X-11.