Saw this clean 1980s? Cadillac at the grocery store....

[keiser31]

Not THAT old, but clean....

[TerryB]

Old enough to be an antique.  Nice car, I always liked that body style even though many referred to them as a Chevy Nova in Cadillac clothing.

[joe_padavano]

That's a 1976-79 Seville, not 1980s. Powered by an Oldsmobile 350 with a prehistoric ANALOG electronic port fuel injection system. I suspect most of them have been converted to carb by now due to lack of parts availability. And while it is derived from the X-body Nova platform, there were enough differences that GM redesignated the Seville as the K-platform. As an example, wheel bolt pattern is 5 x 5", not the 5 x 4.75" pattern used on the X-body cars.

Edited June 21, 2021 by joe_padavano (see edit history)

[joe_padavano]

23 minutes ago, TerryB said:

Old enough to be an antique. 

 

You realize that THIS qualifies to be an antique, right. 😉

 

[TerryB]

With all the discussions on pre WW2 cars it’s a reminder that cars like this qualify too.  My concern would be parts availability.  I don’t know how readily available parts are especially body, interior and trim.

[keiser31]

51 minutes ago, joe_padavano said:

That's a 1976-79 Seville, not 1980s. Powered by an Oldsmobile 350 with a prehistoric ANALOG electronic port fuel injection system. I suspect most of them have been converted to carb by now due to lack of parts availability. And while it is derived from the X-body Nova platform, there were enough differences that GM redesignated the Seville as the K-platform. As an example, wheel bolt pattern is 5 x 5", not the 5 x 4.75" pattern used on the X-body cars.

Thanks. That is why I added a question mark.

[Matt Harwood]

I think the first-gen Sevilles are great cars. Definitely not a rebadged Nova. They feel like Cadillacs and with less weight to haul around, that 350 Olds V8 does a better job than the 500-inch monsters in the bigger cars. We had a nice dark dark blue one that still had its original EFI that worked well--just like a modern car. Turn the key and it starts instantly and idles perfectly. These are on my watch list as they can't be $10,000 throw-aways for much longer, especially not in great colors like this black one. I think we got something in the high-teens for this one:

 

 

Arguably the best Cadillac of the '70s, Eldorado convertibles notwithstanding.

[Rusty_OToole]

45 years old is not exactly a late model. Owners loved those Sevilles and kept them for years, when the typical Cadillac buyer traded his car every 2 years. You used to see them in the driveways in expensive neighborhoods, 10 or 15 years old, still in everyday use and still looking pristine. Come to think of it I don't recall seeing one in shabby run down condition.

They seemed to hit a sweet spot like no other car of the time.

[pfloro]

As Joe stated, it was an early analog FI system. It's roots were from Bendix, Bosch (Jettronic something), and ?. A few years ago, I found some information on it's design. There was 1 injector per port so it was not a throttle body system. However, the injectors were "batch fired" and not sequentially timed to fire during each intake stroke. I don't know how the injectors were grouped. From what I read, the only driveability issue was some stumble/hesitation during engine warm-up. The "computer" engine temperature sensor was mounted right next to the EGR valve. This caused the mixture to be made more lean before the engine had fully warmed up. Aside from that, I was a very good system.

 

Paul

[TAKerry]

Great looking cars! I think they were based on the nova platform but the wheel base was stretched. Every bit a Caddy though. I even like the bustle back sevilles,  and come to think of it even the newer ones. Pop had 2, he had the last generation that was actually called a Seville, then the one after that which was pretty much the same car but newer was called an STS. I dont think that a Seville or Cadillac emblem was even on the outside body anywhere.

[Pfeil]

2 hours ago, joe_padavano said:

That's a 1976-79 Seville, not 1980s. Powered by an Oldsmobile 350 with a prehistoric ANALOG electronic port fuel injection system. I suspect most of them have been converted to carb by now due to lack of parts availability. And while it is derived from the X-body Nova platform, there were enough differences that GM redesignated the Seville as the K-platform. As an example, wheel bolt pattern is 5 x 5", not the 5 x 4.75" pattern used on the X-body cars.

I'll just add that the NOVA - PHOENIX - OMEGA - SKYLARK  X bodies that this K body comes from originally in the 2nd gen Camaro Firebird. The Camaro-Firebird provide the front subframe. As far as the body goes measuring the front fender the X and the K are the same length, measuring the front doors of the X 4 door and the K four door they are the same. Measuring from the back of the rear door to the end of the rear fender the X and K are the same. It's the rear doors and floors that are different - it's a 11" stretch there with more wheelbase 111 vs 114.3 and of course the canopy is different.

  If you live in Ca. or AZ,  those cars have to be forever smog checked and inspected. In Ca that means any car 1975 and above and Arizona anything 1967 on up in metro areas unless using historical plates. That means all the emission systems including FI must be intact and working order just like when it left the factory. 

Edited June 21, 2021 by Pfeil (see edit history)

[TerryB]

I had a 1977 Nova Rally 2dr that has the handling suspension.  It was only a 305 w automatic trans but it’s strong suite was the handling.  Great car overall for the six years I owned it.

 

[joe_padavano]

3 hours ago, pfloro said:

As Joe stated, it was an early analog FI system. It's roots were from Bendix, Bosch (Jettronic something), and ?. A few years ago, I found some information on it's design. There was 1 injector per port so it was not a throttle body system. However, the injectors were "batch fired" and not sequentially timed to fire during each intake stroke. I don't know how the injectors were grouped. From what I read, the only driveability issue was some stumble/hesitation during engine warm-up. The "computer" engine temperature sensor was mounted right next to the EGR valve. This caused the mixture to be made more lean before the engine had fully warmed up. Aside from that, I was a very good system.

 

Paul

 

The injectors were grouped to alternate with the firing order, just like a dual plane intake, and just like the alternate firing of the two injectors in the GM TBI system. The Olds firing order is 1-8-4-3-6-5-7-2, so one batch of injectors fired into 1, 4, 6,  and 7. The other batch fired into 2, 3, 5, and 8. The computer just needed two output drivers that alternated in firing. Early EFI port systems like GM's Tuned Port Injection worked the same way, as you need a crank position sensor to fire sequentially. This analog system also did not have an O2 sensor, so it was always operating in open loop.

 

Edited June 21, 2021 by joe_padavano (see edit history)

[joe_padavano]

3 hours ago, Pfeil said:

I'll just add that the NOVA - PHOENIX - OMEGA - SKYLARK  X bodies that this K body comes from originally in the 2nd gen Camaro Firebird.

 

Actually, originally it was the Nova, Omega, Ventura, and Apollo (which spell NOVA).

[8E45E]

23 minutes ago, joe_padavano said:

 

Actually, originally it was the Nova, Omega, Ventura, and Apollo (which spell NOVA).

I also read it as GM's  'AVON' cars.

 

Craig

[8E45E]

6 hours ago, keiser31 said:

Not THAT old, but clean....

 

 

 

 

What's with that downcast driver's side low-beam?

 

Craig

[Bloo]

Nearly all port fuel injection systems were batch fired in those days. They weren't "timed" to valve opening with very few exceptions. It gave more time for the fuel to vaporize, gave better emissions and driveability, and usually more power. Most systems sprayed half the fuel load for each batch on one rotation of the crank, and the other half on the second rotation to minimize errors by the injectors. There was nothing even remotely timed about it. You can get higher power from timed sequential injection, but it is much tougher to get right.

 

Some cars, mostly four cylinders, fired ALL the injectors in a batch. Those would stop running completely if one transistor failed. Not good. Bosch made a few systems like that as did others.

 

The Bendix/Cadillac system is an evolution of Bendix Electrojector of the late 1950s, the original electronic fuel injection system. Legend has it Bendix sold the patents for everywhere in the world except the US to Bosch, Bosch refined it, redesigned it, and that is where the Electronic fuel injection found on early 70s Volvos and Volkswagens came from. They batch fired. This should not be confused with the largely mechanical Bosch CIS systems found on some Volkswagens. Those CIS systems spray constantly through both rotations of the crankshaft.

 

The main reason everything has timed injection today is that US emission laws require the control system to be able to disable an injector on a misfiring cylinder. Each injector has to have a separate transistor to fire it, and separate wiring anyway. They are also getting better results from timed sequential injection now than they were in the 1990s, never mind the 1970s.

 

The biggest problem I remember with those Bendix/Cadillac systems was that they switched the fuel pump directly from the control box with no relay. It would burn up the plug and the circuit board. It was prudent to add a relay, and repairs on the control box itself were pretty iffy after new ones were no longer available.

 

 

 

 

[joe_padavano]

14 minutes ago, Bloo said:

Nearly all port fuel injection systems were batch fired in those days. They weren't "timed" to valve opening with very few exceptions. It gave more time for the fuel to vaporize, gave better emissions and driveability, and usually more power. Most systems sprayed half the fuel load for each batch on one rotation of the crank, and the other half on the second rotation to minimize errors by the injectors. There was nothing even remotely timed about it. You can get higher power from timed sequential injection, but it is much tougher to get right.

Yes, you need a crank position sensor to do sequential. OEMs do it to be able to better control emissions and mileage. The computing horsepower didn't exist in the 1970s, at least not at a price compatible with a mass production automobile. Batch fire just reads pulses in the distributor and alternates batches to correspond with each spark pulse. It really doesn't matter if you're synced or not that way, you just alternate. I believe the 1984 Grand National was GM's first sequential EFI system in a production car.

[76 Caddy]

1 hour ago, 8E45E said:

What's with that downcast driver's side low-beam?

 

Craig

The upper adjust screw is broken or should I say the plastic it screws into is broken.  I've replaced all of them on both my 76's.  From what I can see of the steering wheel, it is either a '77 or '78.  My Fleetwood was originally EFI but has been converted to a carburetor but my Seville is still original and runs great with 92,216 miles.

 

Tim 

[8E45E]

1 hour ago, Bloo said:

Nearly all port fuel injection systems were batch fired in those days. They weren't "timed" to valve opening with very few exceptions. It gave more time for the fuel to vaporize, gave better emissions and driveability, and usually more power. Most systems sprayed half the fuel load for each batch on one rotation of the crank, and the other half on the second rotation to minimize errors by the injectors. There was nothing even remotely timed about it. You can get higher power from timed sequential injection, but it is much tougher to get right.

 

Some cars, mostly four cylinders, fired ALL the injectors in a batch. Those would stop running completely if one transistor failed. Not good. Bosch made a few systems like that as did others.

 

The Bendix/Cadillac system is an evolution of Bendix Electrojector of the late 1950s, the original electronic fuel injection system. Legend has it Bendix sold the patents for everywhere in the world except the US to Bosch, Bosch refined it, redesigned it, and that is where the Electronic fuel injection found on early 70s Volvos and Volkswagens came from. They batch fired. This should not be confused with the largely mechanical Bosch CIS systems found on some Volkswagens. Those CIS systems spray constantly through both rotations of the crankshaft.

 

The main reason everything has timed injection today is that US emission laws require the control system to be able to disable an injector on a misfiring cylinder. Each injector has to have a separate transistor to fire it, and separate wiring anyway. They are also getting better results from timed sequential injection now than they were in the 1990s, never mind the 1970s.

 

The biggest problem I remember with those Bendix/Cadillac systems was that they switched the fuel pump directly from the control box with no relay. It would burn up the plug and the circuit board. It was prudent to add a relay, and repairs on the control box itself were pretty iffy after new ones were no longer available.

 

 

 

 

From the Seville brochure:

 

Craig

[Ed Luddy]

Always liked the looks of these. Rust killed a lot of them early up here in Ontario. Mostly due to the heavy winter salting. I tried to buy a very nice Naples Yellow with matching yellow leather a few years ago from a local prominent collector. But his wife had sold it the same day to someone who was there before me.

[Pfeil]

20 hours ago, joe_padavano said:

 

Actually, originally it was the Nova, Omega, Ventura, and Apollo (which spell NOVA).

Well if technicality is what we're after and we are talking of X cars from 1975-79 that Seville 1975-79 is based off of,

so Nova,

"Ventura II" ( Not Ventura) -  till 1977 and Phoenix 1978-79 still the same car a new name and marketing blunder,

Oldsmobile Omega,

Buick Skylark in two door coupe and hatchback and Apollo in 4 dr. sedan for 1975, and for 1976-1979 it just Skylark.

How is that?   

[8E45E]

15 minutes ago, Pfeil said:

Well if technicality is what we're after and we are talking of X cars from 1975-79 that Seville 1975-79 is based off of,

so Nova,

"Ventura II" ( Not Ventura) -  till 1977 and Phoenix 1978-79 still the same car a new name and marketing blunder,

Oldsmobile Omega,

Buick Skylark in two door coupe and hatchback and Apollo in 4 dr. sedan for 1975, and for 1976-1979 it just Skylark.

How is that?   

GM's hasty answer to the Energy Crisis, and the beginning of going 'corporate' with badge-engineered cars.  Not counting Canada, where there was the Pontiac Acadian based on the Chevy II since 1962, 1971 saw the release of the Ventura II at Pontiac dealers midway through the model year. Then at the beginning of the 1973, Oldsmobile got their version, the Omega, only to be followed by the Apollo for Buick dealers.

 

Craig

[joe_padavano]

56 minutes ago, Pfeil said:

Well if technicality is what we're after and we are talking of X cars from 1975-79 that Seville 1975-79 is based off of,

so Nova,

"Ventura II" ( Not Ventura) -  till 1977 and Phoenix 1978-79 still the same car a new name and marketing blunder,

Oldsmobile Omega,

Buick Skylark in two door coupe and hatchback and Apollo in 4 dr. sedan for 1975, and for 1976-1979 it just Skylark.

How is that?   

 

I had forgotten that it was the Ventura II. Still, the fact that they spell "NOVA" (or AVON) was too cutesy not to bring up. You forgot the Olds F85 version for the 1976-77 model years (speaking of downsizing nameplates).

[Pfeil]

25 minutes ago, joe_padavano said:

 

I had forgotten that it was the Ventura II. Still, the fact that they spell "NOVA" (or AVON) was too cutesy not to bring up. You forgot the Olds F85 version for the 1976-77 model years (speaking of downsizing nameplates).

Darn, I knew I forgot something ! Well done Joe! I still have a 76 Omega brougham that I special ordered. I have never seen a 76-77 F-85 in person, I believe there is a picture in my 76 sales catalogue on the last page.

 green one at the top

Edited June 22, 2021 by Pfeil (see edit history)

[Pfeil]

23 hours ago, TerryB said:

I had a 1977 Nova Rally 2dr that has the handling suspension.  It was only a 305 w automatic trans but it’s strong suite was the handling.  Great car overall for the six years I owned it.

 

 These cars were not built in haste and were a little over five years in he making.

 The 75-79 cars lead car ( styling bucks ) were first styled as "four door models", which is unusual and this is why the coupes don't look as harmonious. They were a breakaway from the short rear deck long hood cars from 1968-1974. They took their suspensions from Camaro Firebird. When John DeLorean went from Pontiac G.M. to Chevrolet G.M. he insisted the car would handle so he lifted the subframe and suspension from Camaro-Firebird. The basic "international" three box look they used came from G.M. of Germany's OPEL sedans. The New Cadillac also adopted this "international" look and if you read any of the Seville literature the international theme is throughout Seville brochures.

See my 76 4 dr sedan I special ordered, still original paint and interior 115K below, It's suspension and brakes are all 9-C-1 and T/A 

The handling is what made L.A. PD and many other departments pick them up. A friend of mine who worked for L.A. County bought over a hundred of these cars from L.A. Co. Sheriffs when they came off line. The 9-C-1 Nova is a great performer.

  

 

 

Edited June 22, 2021 by Pfeil (see edit history)

[joe_padavano]

1 hour ago, Pfeil said:

Darn, I knew I forgot something ! Well done Joe! I still have a 76 Omega brougham that I special ordered. I have never seen a 76-77 F-85 in person, I believe there is a picture in my 76 sales catalogue on the last page.

 green one at the top

 

Also in the 1977 catalog.

 

[8E45E]

2 hours ago, Pfeil said:

 These cars were not built in haste and were a little over five years in he making.

 The 75-79 cars lead car ( styling bucks ) were first styled as "four door models", which is unusual and this is why the coupes don't look as harmonious. They were a breakaway from the short rear deck long hood cars from 1968-1974. They took their suspensions from Camaro Firebird. When John DeLorean went from Pontiac G.M. to Chevrolet G.M. he insisted the car would handle so he lifted the subframe and suspension from Camaro-Firebird. The basic "international" three box look they used came from G.M. of Germany's OPEL sedans. The New Cadillac also adopted this "international" look and if you read any of the Seville literature the international theme is throughout Seville brochures.

See my 76 4 dr sedan I special ordered, still original paint and interior 115K below, It's suspension and brakes are all 9-C-1 and T/A 

The handling is what made L.A. PD and many other departments pick them up. A friend of mine who worked for L.A. County bought over a hundred of these cars from L.A. Co. Sheriffs when they came off line. The 9-C-1 Nova is a great performer.

  

 

 

The Edmonton City Police department had a fleet of those in 1978.

 

GM tried to move them upmarket with the Chevrolet, Pontiac, and Buick versions by dropping the low-line names by 1979 when that body style ended.  The Nova was replaced with the Concours, Pontiac with the Phoenix, and Buick with the Skylark.   The new Chevrolet version of the 1980 FWD X-body got renamed Citation, while the remaining two, and Oldsmobile Omega kept their nameplates.  Of course the Nova name reappeared in 1985 on the Toyo-let produced at the NUUMMI plant in California, which is now the home of Tesla.

 

Craig

[Pfeil]

20 hours ago, 8E45E said:

The Edmonton City Police department had a fleet of those in 1978.

 

GM tried to move them upmarket with the Chevrolet, Pontiac, and Buick versions by dropping the low-line names by 1979 when that body style ended.  The Nova was replaced with the Concours, Pontiac with the Phoenix, and Buick with the Skylark.   The new Chevrolet version of the 1980 FWD X-body got renamed Citation, while the remaining two, and Oldsmobile Omega kept their nameplates.  Of course the Nova name reappeared in 1985 on the Toyo-let produced at the NUUMMI plant in California, which is now the home of Tesla.

 

Craig

The NOVA name was never replaced.

In 1975 the upscale NOVA was called the NOVA LN ( Luxury NOVA ). Then NOVA Custom, NOVA SS, and NOVA.

In 1976 the LN became the Concours, and other NOVA's were the Nova SS and the standard NOVA.

In 1977 There is CONCOURS, NOVA Rally (replaces the SS) , and NOVA.

In 1978 the CONCOURS is dropped and the NOVA CUSTOM becomes top dog, then NOVA Rally, and plain NOVA. NOTE: The CONCOURS name was dropped to move NOVA down market to take competition away from the new downsized intermediates that had come out.

1979, with the same car lineup as 1978  is a 1/2 year production car ending to make way for the "NEW" X cars.

 

As I mentioned before the BUICK ( 1975-1979  always had the Skylark name ( the one year exception would be the 4door 1975 Apollo, but the coupe and hatchback were called Skylark). 

Edited June 23, 2021 by Pfeil (see edit history)

[8E45E]

9 hours ago, Pfeil said:

As I mentioned before the BUICK ( 1975-1979  always had the Skylark name ( the one year exception would be the 4door 1975 Opollo, but the coupe and hatchback were called Skylark). 

The Apollo came out in the middle of the 1973 model year, a year-and-a-half prior to Buick calling it a Skylark.

 

Craig

[Pfeil]

3 hours ago, 8E45E said:

The Apollo came out in the middle of the 1973 model year, a year-and-a-half prior to Buick calling it a Skylark.

 

Craig

Yes , but we are talking about the new ( 1975-79 ) X and K cars which are related and the platform from which they sprang from the Gen2 F car.

Edited June 23, 2021 by Pfeil (see edit history)

[8E45E]

3 hours ago, Pfeil said:

Yes , but we are talking about the new ( 1975-79 ) X and K cars which are related and the platform from which they sprang from the Gen2 F car.

The Apollo name was still used in 1975.

 

Craig

[Pfeil]

36 minutes ago, 8E45E said:

The Apollo name was still used in 1975.

 

Craig

This is the third time and here is part of the post from the last time.

 

" As I mentioned before the BUICK ( 1975-1979  always had the Skylark name ( the one year exception would be the 4door 1975 Apollo, but the coupe and hatchback were called Skylark). "

[8E45E]

11 minutes ago, Pfeil said:

" As I mentioned before the BUICK ( 1975-1979  always had the Skylark name ( the one year exception would be the 4door 1975 Apollo, but the coupe and hatchback were called Skylark). "

What difference does it make?   

 

Buick actually used the Skylark name as far back as 1953, and until 1998 on different platforms.  Don't be at all surprised if the 'Skylark' name eventually makes a comeback on an SUV.

 

Craig 

[Buffalowed Bill]

No disrespect to John, but if Keiser couldn't nail it the first time what does that mean for its lack of visibility? I bet if you went to fifty car shows or cruises, you wouldn't see another like it. I'm just saying that I go to car events to see the unexpected. At some point an individual car's survivability becomes the story when we know that 99% of its brethren are gone.  

[keiser31]

1 hour ago, Buffalowed Bill said:

No disrespect to John, but if Keiser couldn't nail it the first time what does that mean for its lack of visibility? I bet if you went to fifty car shows or cruises, you wouldn't see another like it. I'm just saying that I go to car events to see the unexpected. At some point an individual car's survivability becomes the story when we know that 99% of its brethren are gone.  

Those years are a blurr to me. If I had taken the time to see the numbers/date on the taillight lens, I may have been able to tell. I appreciate the lessons on the model that all you folks enlightened me with.

[8E45E]

2 hours ago, Buffalowed Bill said:

No disrespect to John, but if Keiser couldn't nail it the first time what does that mean for its lack of visibility? I bet if you went to fifty car shows or cruises, you wouldn't see another like it. I'm just saying that I go to car events to see the unexpected. At some point an individual car's survivability becomes the story when we know that 99% of its brethren are gone.  

That is very true for 1960's Austin Cambridges, Morris Oxfords, and the smaller FWD 1100 models.  Once a very common site here, but nearly all got replaced with Toyota Coronas, Corollas, and other similar size Japanese cars, only to see those from the 1970's disappear as well.    1960's British family sedans, and early 1970's Japanese cars do draw a crowd at a car show.

 

Craig

[Pfeil]

1 hour ago, keiser31 said:

Those years are a blurr to me. If I had taken the time to see the numbers/date on the taillight lens, I may have been able to tell. I appreciate the lessons on the model that all you folks enlightened me with.

I appreciate you taking the pictures and starting the topic. It's interesting the 75-79 Seville turned out the way it did. If Bill Mitchell had had his way the original concept would have looked more like a 1980 Seville with it's bustle back. I can't remember all of the politicking and trade-offs that went on to get it to where it ended up for production. The history is just as fascinating as the engineering aspect of the car. Compared to the X cars from 75-79, the K cars have really started to appreciate in valve. I can remember just a few years ago you could get a very nice one for under 10K. Not so today, and same holds true for 77-79 coupe de ville and de ville, 80 & 81 ok but not as strong with the 368 especially 81's V-8-6-4 but that can easily be deactivated.   

[Paul Dobbin]

15 hours ago, Pfeil said:

, 80 & 81 ok but not as strong with the 368 especially 81's V-8-6-4 but that can easily be deactivated.   

        Deactivated?    I bought a 1981 V8-6-4 in 1987.   Great car that seldom used the 6 cylinder option.  We added atrailwe hitch an towed a Airstream the

       lenght of the Blue Ridge Parkway.  Only problem was brakes getting off the Parkway.   Always herad how awful that 8-6-4 was, but never experienced 

       a problem with it.   After two years, sold it and bought 1977 GMC Eleganza and a 66 VW to tow, then a trailer for our old cars.   The 81 Seville was a luxury

       car in every respect, just not a tow vehicle.   Reputation was besmerched by auto officinatos that never owned one.  

[Pfeil]

3 hours ago, Paul Dobbin said:

        Deactivated?    I bought a 1981 V8-6-4 in 1987.   Great car that seldom used the 6 cylinder option.  We added atrailwe hitch an towed a Airstream the

       lenght of the Blue Ridge Parkway.  Only problem was brakes getting off the Parkway.   Always herad how awful that 8-6-4 was, but never experienced 

       a problem with it.   After two years, sold it and bought 1977 GMC Eleganza and a 66 VW to tow, then a trailer for our old cars.   The 81 Seville was a luxury

       car in every respect, just not a tow vehicle.   Reputation was besmerched by auto officinatos that never owned one.  

From Mac's motor city garage;

What went wrong? To make a rather long story short: GM’s early throttle-body electronic fuel injection technology wasn’t fast enough, nor sophisticated enough, to deliver seamless operation. And the electro-mechanical solenoid setup that manipulated the rocker arms wasn’t up to to sufficient speed, either. Four-cylinder performance was as horrible as you imagine, while the system would also hunt around among the 4,6, and 8 cylinder modes at steady road speeds, among other problems. The technology required to perform cylinder deactivation properly wouldn’t be ready for prime time for another decade or more.

After more than a dozen attempts to revise the system, Cadillac discontinued the feature at the end of the 1981 model year and advised its dealers to disable it for the customers who were having problems.  The V8-6-4 was a memorable failure in the history of Cadillac V8s, but unfortunately, it wouldn’t be the last.

 My sister had a 81 Sed. DeVille that my brother in law disabled the function and turned the car into just a V-8. I drove the car and can tell you ( I worked for a competitor ) and a one time I used to prepare all of our cars for magazine road test. A V-8-6-4 car like the Cadillac would have never made it out of the engineering garage.

 Couldn't imagine a car line letting the car go to the public ( can you say Gov. CAFE standard is why) and then the next year even worse, can you say HT4100!