(first posted 12/18/2013) Imagine lifting the hood of a 1967 Cadillac, and seeing this alloy SOHC V12 nestled there. It’s hardly a far-fetched notion. In the mid sixties, Cadillac came very close to replacing its aging V8 engine with a modern OHC V12. There have been references to this program, but there was almost no photographic evidence of these intriguing engines. A while back, blog.hemmings finally convinced Cadillac to send them some detailed pictures and more information.
this one is at the GM Heritage Center
Six prototypes were built in 1963 and 1964, all with a 60-degree bank, chain driven camshafts and hydraulic finger followers. The initial displacement was 7.4 liters, but an 8.2 was also built, which corresponds exactly to the size of the new V8 engine that eventually was built instead of the V12. Various induction systems were tried, including single four-barrel, dual four-barrel, and triple two-barrel carburetors, as well as fuel injection. Output was between 295 to 394 horsepower, and from 418 to 506 lb.ft. of torque.
According to historian Karl Ludvigsen, the V12 engines were planned to make their initial appearance in the new FWD Eldorado in 1967. GM drivetrain engineers at that time were considering a transverse engine orientation for the FWD system, and protested that the V12 would be too long. But supposedly they then relented, and switched to a longitudinal FWD system which could have accommodated the V12. But then the V12 program was killed, “due to the poor performance of the test engines and due to a predicted inability for the engine to meet anticipated emission controls”
What seems odd to me about that statement from Ludvigsen is that I have never heard of GM’s Toronado FWD program considering transverse engines, as Olds had been working on FWD prototypes since 1960 or earlier, and to the best of my knowledge, they were all longitudinal. Certainly Cadillac couldn’t have been considering their own FWD system; that just makes no sense.
As it turned out, the V12 died for other reasons. But it sure makes for fascinating speculation to think of a whole generation of Cadillacs with V12s under their hoods. It came mighty close to happening.
This would have been pretty neat, but the thing is the all new Cadillac 7.7 litre 472 V8 that came out in 1968 already made 375hp and 525lb-ft of torque with 1/2 the complexity and 3 times the durability.
But 1/3 the cool factor.
I dunno, there is something cool about the having largest displacement engine in a production car at the time.
Yup, ask the man who owned one. Even in my 6500lb Ambulance with 2.7x gears in the back, I could still break a tire loose with the 472! Every time I did it, everybody in the intersection was looking all over trying to figure out which car it was!
Of course, the 1970 Caddy 500 was the pinnacle of displacement and torque, before GM dropped the compression ratios in 1971.
my grandad had a 1918 v 12 cadillac
A buddy of mine in high school picked up a 1970 Cadillac hearse off of eBay back for something like $1,000 circa 1997-8. Went to Pennsylvania to get it.
The only thing it couldn’t pass was a gas station. Holy fudge would that car go! And yeah, it could definitely break the ass-end loose if he put his foot into it.
I once drove a 500cu in (8.2L) ’72 Eldorado convertible. Handled like a boat. Front wheel drive and such a marshmallow suspension, when I floored it all the bloated weight would heave back on the rear shocks and cause the front tires to peel out as they nearly went airborne.
There was also an 8.2 L version of the V12 built. And I suspect there might have been room for more.
Engineering excellence is the hallmark of true luxury brand, The customer buys the chassis and has it bodied by a coachbuilder over the top powertrains are perfect to generate snob value and sales a kinda later day Duesenberg, Giant miss step by Cadillac the brand could have been “something” a very fast ambulance for instance it would have put Cadillac a giant leap above Lincoln or Imperial and they would have priced it accordingly like an early Maybach
In the mid-60’s Cadillac was already “a giant leap above” Lincoln and Imperial in terms of prestige. They probably felt they didn’t need something like this to retain the throne. They overlooked that that prestige was built on a history of engineering excellence.
Given all the specialty tooling that was probably required for the V12, it may not have made sense to put it in production in terms of ever seeing any return on investment. Add to that the fact that it had no advantage over their big V8’s on paper and the looming threat of not meeting the coming emissions requirements.
If GM had green-lighted this engine, we’d probably be talking about it today in the same light as the Caddy 4-6-8, the Olds 350 diesel, and the aluminum Vega engine, and possibly the Lincoln-Zephyr flathead V12.
What I think is unfortunate is that they didn’t take what they learned from this exercise about building SOHC engines and apply it to their V8’s. If the big Caddy V8’s were all SOHC, that would have been beneficial in various ways: performance, “snob appeal”, emissions, etc.
A GM V-12 could’ve also precipitated a technological arms race with Ford and Chrysler that would’ve bankrupted the smaller two companies.
Chrysler and Ford may not have been working on a V12, but they weren’t exactly standing still either. If Cadillac had brought out the V12, Chrysler may not have cancelled the “ball-stud” Hemi project, which would have replaced the 440.
Chrysler was also developing a DOHC version of the Hemi, which was cancelled when they learned that NASCAR planned to outlaw DOHC engines. They also had their Turbine cars running around in consumer trials from 64-66. They were also doing R&D on new variants of the slant-6.
Oh man, yet another reason to hate NASCAR. DOHC production experience would have put Chrysler ahead of the curve that everyone had to climb eventually. And what an engine that could have been! So much for “Racing Improves the Breed”.
Was one of the Slant Six R&D variants a siamesed V-12? 😉
Eh, believe it or not, Olds, Pontiac and Buick all played around with DOHC headed V8’s in the late 60’s.
If these V12s had been available could Cadillac have been a Mercedes fighter?V12s were once the preserve of high end cars and not seen in mass produced cars until the Jaguar V12 of the early 70s.More cylinders or more cubic inches a fascinating what if.The initial problems were not something that couldn’t be overcome with research and development.Thank you for another great read and photos Paul
Paul, you say “Various induction systems were tried, including single four-barrel, dual two-barrel, and triple two-barrel carburettors” – don’t you mean dual four-barrels? Dual two-barrels seems a bit odd…..
You’re my copy-editor today! Yes, that was a typo. Fixed now.
Great article – close to 60 and a car guy but have never heard of this V-12 before – and I thought I was well read…….
Another reason I enjoy this site so much…….
What effect an OHC V12 Cadillac, especially in a car engineered properly in other areas, may have had on the marketplace is an interesting thought. It may have elevated Cadillac above Mercedes during the Mercedes invasion of the US during the late 1960s, and possibly even made Cadillac internationally popular as a car for the superrich who normally would buy something like a Mercedes 300SEL 6.3 or Maserati Quattroporte. We can only speculate.
If I were one of the winners of the recent massive lottery jackpot announced this week, I would obtain the blueprints to this engine, commission someone with the engineering skill and foundry access (Edelbrock, perhaps?) to re-create it, and install it in a suitable Cadillac — say, a 1949 convertible, a 1966 Fleetwood Brougham, or a 1967 Eldorado. Of course, this kind of thinking is why lottery winners waste all of their prize money after a few years. 🙂
But Cadillac didn’t need anymore image enhancement in the late 60’s, it already is a more advanced car in terms of features, ease of operation and durability than both the Mercedes and way past the Quattroporte. I mean a 300 SEL didn’t even have air conditioning integrated into the dash for christsake. To me a late 60’s and even and early 70’s Cadillac is still a more complete car than an equivalent era Mercedes, the MB may be very nicely engineered, but they were sorely behind in most of the luxury and comfort and convenience features that were common on most Cadillacs from the era.
“To me a late 60′s and even and early 70′s Cadillac is still a more complete car than an equivalent era Mercedes, the MB may be very nicely engineered, but they were sorely behind in most of the luxury and comfort and convenience features that were common on most Cadillacs from the era.”
No doubt about that.
The Cadillac superiority over Mercedes is only from an American perspective, Europeans place handling, braking and performance much higher than air conditioning. You really only need air conditioning in countries closer to the Mediterranean, a heater is far more useful in Northern Europe. I have driven a Fleetwood on British roads and it could not keep pace with an ordinary family car with an engine less than 2 litres. With their huge engines they may be quite fast in a straight line but only the Romans seemed built straight roads, it is too big for most European roads, and its cornering is all tire screaming drama where European cars don’t even notice; but If I lived in America and drove on your roads, or even Australia , I would drive a Lincoln, Thunderbird , Imperial or Cadillac, probably early 60s, they are so glamorous
We’re all talking with the advantage of 50 years of hindsight.
Back in the 60’s, it probably wasn’t needed because Cadillac was at the top of its game, and a V-12 would have been overkill. Delightful, sassy overkill; but overkill nonetheless.
From what we’ve seen in history, the V-12 can now be considered a missed chance. It would have elevated Cadillac even higher in prestige, making it a much more special car. Especially if it was limited to models only well above the standard deVilles. Which in turn would have (take your pick): a. Given the car enough status within GM to keep it from getting cheaped down like it was in the 70’s and 80’s; or, b. Assuming the history of the 70’s and 80’s continued unchanged, at least Cadillac would have been coming down from a higher height, which, hopefully would have it crashing out at a higher level.
I think the V16 Cadillac is a legend and first of all it is a legend because it is a V16..
A V12 Cadillac surely would have been more of a stand out, than the regular V8 Brougham.
I think back in the day Cadillac made the V16 it was a world class car for that brief window of time. I think it was Cadillac’s finest hour. They are among my favorite cars of all time.
This would have been a boon to Cadillac provided that it did not have the problems of the 4.1/4.5 and early Northstars. No doubt, it would have been more expensive to build than the 472/500 cast iron V-8.
Can anyone please explain the pros and cons of a V12 versus a V8 engine? Suppose two engines a V12 and a V8 have the same displacement, say, 8 Liters. and the same type of fuel injection, same compression ratio, to make things more equal. What would make one better than the other? As someone else mentioned, the V12 sure sounds more complicated and more chances of things to go wrong, mechanical failure ETC.
The V12 would be smoother running. There’s no smoother engine,realistically, given that it combines two inline sixes that are inherently smooth. Of course, V8s have been taught to be quite smooth too, but a V12 runs like the proverbial turbine, a word this is intrinsically used in describing them.
The V12 would have a less favorable torque curve, as in the case of any two engines the same size, the one with fewer cylinders will tend to make its maximum torque at lower rpm. Of course on engines this size, that probably wouldn’t be much of an issue.
The V12 would be thirstier, given its greater internal friction, and its higher torque peak. In that class of car back in the sixties, that didn’t really matter much.
Mechanical failure: that really doesn’t have to be an issue, if it’s built right. Most engine mechanical failures are not in their primary moving parts. The greater risk would have come from building an all-alloy engine, and the greater complexity of the OHC heads. As we know, GM had some very real issues with aluminum engines, like the B-O 215 V8, and later the Vega engine.
Most of those problems could have been avoided, but the risk was undoubtedly greater. There’s no question that Cadillac avoided a lot of potential risk by sticking to their tried-and-true iron V8 OHV V8s.
To sum up: the main advantages of the V12 would have been in superlative smoothness and prestige.
Sir! Thank you very much for this well researched answer! It absolutely answered all of the questions that have percolated in my head since the 1990’s! I can now put this one to rest now thanks to you!
I love this site and being able to ask experts like you questions like this. 🙂
I believe Paul, you’ve got a spot-on statement. The extra cylinders would’ve added a lot of prestige, but the cost analysis based upon tests in the day, the casting technology (not a strong suit of GM or America in the day) compared vis-a-vis with an iron block V-8 (not to mention the primitive emission controls soon to be coming during this period’s development days) made the decision – a wise one – to stick with a large displacement iron/iron V-8, the smart safe bet.
Packard was developing a V-12 variant of it’s V-8 during the troubled ’54-’55 period, but Packard being Packard (bled by the father-son teams at Studebaker!) didn’t have a pot to piss in for intense development nor a window to through it out of. Hindsight seems to favor that a Packard V-12 wouldn’t have made any difference as James Nance couldn’t get financing for his all new body plan that was supposed to happen for 1957 . . . .
It’s another why didn’t they/what if.Packard had built successful V12s before the war and had built the Rolls Royce Merlin V12 aircraft engine under licence so in theory it should have been easy.
It would be possible, but not especially “easy.” Cost was not a factor when building the Merlin, but it would most certainly would be in a car engine.
Ford also design a state-of-the-art aircraft-grade OHC V12, which not being adopted by the AAF, was chopped & derated into the GAA V8 for some models of the Sherman tank. But the V12 was restored for postwar heavy tanks, albeit still derated.
Go for a ride or drive a Jaguar XJ-12 sedan (my boss in Indiana loaned me one for 2 weeks)…. you will understand. Pure “silk” when accelerating. “Pace with grace.”
Smoothness…silky smoothness. It’s an inherently balanced design.
It reminds me a bit of the V16 Cadillac engines of the 1930s, which (if I remember right) were reputed to be complicated and fragile yet underpowered.
Still, this kind of overkill (if mechanically sound) is what separates a mass-market luxury vehicle from the truly exclusive. As Carmine has pointed out above, Cadillac was well ahead of its competitors in the mid-1960s (though if you can set aside the question of style, I think the 1967 Imperial might have been a better car) and so didn’t really need a V12 to move the units.
This would’ve been great for a halo car, a vehicle that has simply no competitors at all. Perhaps it would have been a worthy successor to the 1957 Eldorado Brougham.
Maybe the transverse V12 was being considered for this 18ft wide concept, though the Johnson administration nixed a plan to widen all of the nations roadways for this car.
Cartoon Don Draper seems to like it though….
Laughing Out Loud!
This wasn’t the last V12 concept from Cadillac, the 1988 Solitaire show car had a 6.6 litre DOHC V12 designed by Cadillac and Lotus Group, which GM owned at the time. It made 430hp and 470lbft of torque, I wonder how far it got along in actual development, it was supposed to be a runner.
That’s pure pornography.
I actually tested this engine on the dyno so yes, it was a runner. Lotus made just 3 of these engines and I recall it was a £1.5M project for Lotus.
I’ll probably get blasted for this, but I think that Cadillac made the right decision for the time. Their existing large-displacement engines made massive low-rpm torque, which is exactly what you need to get off the line with a 4500lb lead sled. I’m sure that the V-12 wouldn’t have been a slouch either, but from a buyer’s perspective (mostly doctors, lawyers & business owners in the small town that I grew up in) I don’t know that it would have helped them sell any more cars.
I still think that Ford (and Dodge) made a mistake by going to their modular V-series engines in their trucks back in the late 1990s. I have a 460 in my 1990 F350 crew cab, and it has amazing diesel-like torque. Even with 3.55 gearing, around town I usually upshift around 1100-1200rpm. You can’t do that with the mod motors in a vehicle that weighs over three tons.
My roommate had a 1997 Mustang SVT Cobra with the DOHC motor that he let me drive once, and I was let down – you had to rev the bejeebers out of it to get any power – not what I was expecting – I was used to that low-end grunt that puts you back in your seat right away (heck, even the 5.0 in the Mustang gave you that kind of feeling) at much lower RPMs.
I may have even seen one of these engines in the flesh – back when I attended GMI (now Kettering Univ) in Flint in the 1980s, they had a bunch of R&D motors from various GM divisions in their engine lab (which just sat gathering dust back in one corner IIRC) – I do know that they were playing with the HEI distributor prototypes back in the late 1960s as some of the test engines from that era already had them (also possible that they were added later I suppose).
I’ve never heard of any Dodge engine being referred to as a “modular” engine, only the Fords. Sounds to me like you’re mostly bemoaning that they discontinued the big blocks like your 460 and only offered smallblocks in the pickups, which is where the wide torque band disappeared. There is no replacement for cubic displacement!
If this had made volume production, just imageine what hot-rodders would have been swapping them into not all that many years later; and it might have made for some interesting pages int he Jegs and Summit catalogs.
Although the V-12 has more friction than the V-8, wouldn’t it have intrinsically better breathing, i.e., 24 valves vs 16? So if a regular Cad performed comfortably up to 80 mph or so, the V-12 could still have plenty of juice. Of course, the other factor would be making a car that didn’t have so much lift at those speeds that it felt unsafe regardless of its powertrain’s capacity.
I think the opportunity, which wasn’t necessarily that big of an opportunity, was for a higher-revving car that would have beat the snot out of the Mercedes Pagoda and C/R107 cars. I like those Mercedes, but if there was ever a mass-production car that dominated a market because nobody built a straight-up competitor, that’s it. If the corporation must be miserly, it could have been the first F-body or A-body variant with I.R.S.
This is true, although one might argue that with typical Cadillac power curves the better breathing would not be significant enough to be worth the expense; Cadillac’s contemporary V-8s had their gross power peak at 4,800 rpm and the net peak was lower than that. Most Cadillac engines spent their lives well under 4,000 rpm and if better breathing was the goal, a SOHC 3V V-8 conversion like the ones Pontiac was playing with would have been much cheaper.
The major motivation for the project, aside from prestige, was smoothness. One of the concerns with huge-displacement engines was that above a certain threshold of volume per cylinder, you start getting more roughness (which is still true today — you see this with V-6 engines that are silky at 3.0 liters and get increasingly raspy as they approach 4.0 liters). An eight-cylinder engine with a 500 cubic inch (8,200 cc) displacement is at more than 1,000 cc per cylinder, where a 12 brings that down to about 680 cc per, in addition to the greater intrinsic smoothness of the V-12 configuration itself.
The breathing depends a lot more than just that. It depends on how relatively big those valves are, and the combustion chamber, porting, valve timing, etc…Given the power being made by OHV V8s engines such as the Corvette’s shows how much development was/is left in that design, from a power point of view.
Did GM ever confirm the bank angle of the surviving prototypes? Since the V-12 was a clean-sheet design, you’d think it would be 60 degrees and Ludvigsen describes it as such, but as Daniel Strohl notes in that article, when Dick Langworth had written about the engine back in the late ’70s, he reported that it had a split-pin crank like the latter-day 3800 V-6, which a 60-degree engine wouldn’t need. Langworth thought it might be 90 degrees, presumably to share tooling with the V-8s, but the photos (which Langworth didn’t have — Cadillac wouldn’t release them back then) certainly don’t look like 90 degrees; Strohl thought maybe 75.
One of the potential problems with this engine is that it was supposed to have an die-cast aluminum block without liners, using a new process called Acura-Rad. That sort of thing is pretty common today, but that approach didn’t work out so well for the Vega in the early ’70s and I don’t know how happy Cadillac would have been with it five or six years earlier. GM had found die-cast aluminum blocks problematic enough with iron liners; trying to go without was probably asking for trouble.
The earliest Oldsmobile FWD prototypes did indeed have transverse engines, but because Olds didn’t have anything like a transaxle at that point, they used two different chain drives to transmit engine torque to the halfshafts. Oldsmobile eventually conceded that the dual chain system was too cumbersome and inefficient and went for what became the TH425 unit, which could be used with a lightly modified longitudinal engine. (I still don’t know what kind of arrangements, if any, GM made with Ford over the Fred Hooven patent for that concept. It’s possible that Oldsmobile experimented with the dual chain setup as an attempt to work around the Ford patent — which is quite broad — before deciding the latter was just more practical, but that’s pure speculation.)
Throw a protractor/compass on this picture of the front of the engine, and you’re likely to get the (obvious) 60 degrees that I did. How could anyone possibly think that looks like a 90 degree engine? Or even 75?
Langworth’s article (circa 1978) was done without benefit of photographs, which Cadillac refused to release. I haven’t seen the engine in person and the photos GM Media Archives sent me weren’t from end on. If the engine is indeed 60 degrees, I’m not sure where the split-pin crank came from; that was why Strohl suggested 75 degrees.
Interesting to note that the one pictured at the GM Heritage Center has the spark plugs on the intake side of the head, like the GMC 305 V6, the others on exhaust side. And the fuel pump is on the opposite side as well.
Interesting, the oil filler and power steering pump have different places too, I imagine that the one in the heritage center might be a real motor and the BW picture motor some sort of foam mock up.
The Heritage Center engine is the later version, more fully developed. A number of these engines were built, to try out different configurations.
The design of the fuel pump says the one in the color pictures is the older version having the serviceable, bolted together fuel pump while the engine in the black and white photo has the later non-serviceable, crimped together fuel pump. Now they could have replaced the fuel pump with what they had lying around to fill the hole before putting it on display. the crimped style pumps didn’t hit production vehicles until 65/66. The fuel pump bolt pattern is pretty standardized.
By “older” I meant more fully developed. And I’m just repeating what was said over at Hemmings blog, based on their observations of certain aspects of the engine in the BW shots, which apparently is missing some key aspects in its block. Does anyone actually bother to make the jump to the original source?
I actually read that article some time ago and did go through it again before posting the comment. There are some issues with said article. The big one is this line ” Despite the accessories bolted to the engine, the one in the (B&W) photos is obviously still somewhat roughed-in, with cylinders and pushrods open to the air; the engine at the Heritage Center is a little more refined and looks production ready.” – See more at: http://blog.hemmings.com/index.php/2010/04/14/success-cadillacs-ohc-v-12-engine-photos-found/#sthash.pmq1v1JF.dpuf
Being an OHC engine it of course does not have pushrods. I can only assume that the author is mistaking the head bolts for pushrods based on the photo. As far as the cylinders being open to air you see something similar, including the exposed cylinder head bolts in the HT4100.
Of course, lest we forget, General Motors DID build a production V12 in the 1960’s, albeit in a more prosaic ride than a Caddie. Covered here a couple of years ago….https://www.curbsideclassic.com/blog/the-gmc-twin-six-v12-702-cubes-275-hp-at-2400-rpm-630-ft-lbs-at-1600-rpm/
More on the GMC front. . .
The most curious part about it is probably that it’s not two straight sixes stuck together, but two V6s stuck together, which were an odd choice for heavy duty to begin with.
It actually is neither, KW. It’s a unique twelve cylinder block and crankshaft, although it DID use four heads and some internal bits from the 351 V-6, as Paul pointed out in his post about the motor.
Most interesting; histories often benefit, decades after the fact or period in question, when new info or pictures surface.
Something in Paul’s second paragraph beneath his third engine photo, about transverse FWD engine placement at Oldsmobile, caught my attention, as I thought I had read a contradictory statement in another thread. Here is the statement I recalled, from the last post in this thread https://www.curbsideclassic.com/curbside-classics-american/curbside-classic-1966-oldsmobile-toronado-gms-deadly-sin-16-lets-try-a-different-position/
Bill was speaking of a Y-body car, not the Toronado, so perhaps there is no contradiction here. Has there been any transverse-V8 FWD car in production, anywhere ?
“Has there been any transverse-V8 FWD car in production, anywhere ?”
The Taurus-based V8 Lincoln Continental from the late 90s? And wasn’t the Yamaha V8 in the origianl Taurus SHO transverse? And the Cadillac Deville from 1985? Or do I misunderstand your question?
Just about every Cadillac from 1985 on until the end of the FWD era, except the last of the RWD Fleetwoods. In other words, millions of them. And there was the V8 powered FWD Impala.
It was actually the second gen Taurus SHO; the first one was a V6.
Buick Lacrosse offered the 5.3 V8 briefly. Lucerne and the last Bonneville had Northstars as options. Also, the 4.0 in the Olds Aurora.
Not sure how I missed this the first time around. Captain Hindsight says that Cadillac made the right call. As pointed out above, the unlined aluminum block would have been problematic. And then there came the 1973 Arab oil embargo and Energy Crisis 1.0. It is fun imagining Lincoln running ads about its economical 460 compared with “Luxury Car C).
Imagine the quality issues with this motor, sounds like they’d make the Vega look like a Corolla. And, Oil Crisis 1 would have been heck at Caddy HQ.
I think a pushrod V12 in the 1957 Eldorado Brougham instead of the all the high tech gadgets of dubious value, particularly the air suspension, would have been more sensible. Cadillac was planning the Eldorado Brougham to be a much nicer car than the Fleetwood Sixty Special, priced about a $1000 more than the Eldorado convertible until the Continental went into production upstaging Cadillac. Had Cadillac not gone over the top with the Eldorado Brougham it might have been successful with sales of a 1000 or so annually.
An OHC engine for Cadillac would have been a waste without a better transmission. OHC’s are generally designed for higher speed performance, otherwise a pushrod is just as good. So to get the most out of a higher performance engine, an overdrive automatic would have been best, allowing a higher performance axle ratio to be used, but allowing the engine to run slower at highway speeds. GM was so late in designing the Turbohydramatic that they would have been better off if they had designed it to be upgradable to an overdrive gear in front of the torque converter (engine->overdrive->torque converter->driveshaft).
Thanks, JP and Paul. Clearly I haven’t been under the hood of a modern American car in a while.
My friend who’s owned a Caddy DTS for the last 7 or 8 years, has no idea whether the car has front or rear drive, and I wasn’t able to help with that. Wikipedia answered the question — barely, by mentioning that the previous car, the STS, was rear-wheel driven.
The DTS is front wheel drive and the engine is a V8, a double overhead camshaft engine with four valves per cylinder. The last STS was rear wheel drive, but the first STS was front wheel drive and was first in production for the 87 model year.
Who blew the dust off this one? LoL
Pic #3 seems to show a production ’64 Cad adapter plate at the engine’s rear, so they may have been fairly serious about a running mule in that time frame.
To be fair with 20/20 hindsight, if built, 12 couldv’e been a dud and brought on Cadillac’s “junk engine” stigma decades sooner.
Great article! I had no idea that this was in the works then. Like some have mentioned, perhaps this may have ended up being something akin to the 4-6-8 engine, the Vega aluminum, the HT4100 aluminum/ iron issues, GM diesel, or even like the Northstar. Or maybe like early GM fuel injection and the problems that it brought. The power levels not being better than the 472’s output makes me also ask the question: even if Cadillac did manage to up the power levels significantly, would they have a transmission capable of handling the power? Between the tooling costs of the engine and (assuming) a beefed up transmission, it must have cost significantly more to produce.
The V16 engine in 1930 did not require a beefed up transmission. This is because the smaller cylinders produce smaller power pulses.
Thanks, SOITWW. My friend really likes driving his car, though it’s hard for him to articulate why. He says he got it away from the dealer, whose personal car it was. It has a deer-watcher sensor in the middle of the grille, replacing the insignia. People ask if he lost the badge . . .
Very interesting stuff. I had read a bit about this engine, but I had not seen it in photos. Too bad this twelve was a dead end, it would have helped Cadillac stand out even more as the top American luxury marque. And it would have produced the first (the only?) FWD V12 in the world.
I find it rather odd that GM who in it’s Allison division could come up with a successful V12 engine and build almost 70,000 of then during WW2. They could have used some of the technology when trying to build a Cadillac V12. I also wonder why when they had a successful diesel engine division EMD that they did not use their knowledge to create a automotive diesel engine. I realize the divisions were supposed to be semi autonomous, but the entire idea of a corporation is to the parent company money. Maybe that is the key to their ultimate demise. I realize the automotive industries have a different set of parameters but come on guys there is no reason to reinvent the wheel.
Imagine the prestige if Cadillac had built a droptop roadster in 1960, say one quarter larger than the Corvette, and crammed with every convenience possible and that period’s styling, with this V-12. And a fuel injection option.
The ultimate GM halo car.
Yeah, that would have been cool to see. Though, you wonder if it would have been like the Allante……sporty luxury didn’t do so well at that point, so you wonder if it would have done much better in the 60’s. Part of me wonders if the reason why the V12 got the axe, was because they would have to charge so much for whatever vehicle that they put it into and go very high end……..Ford already found that the Thunderbird sold way more as a more practical four seater, and by the end of the 60’s, Cadillac was already on its way to lowering its standards of quality and making things cheaper, which had ended up in them de-valuing their marque and reputation, so a really high end car wouldn’t have likely been in the bookkeeping at GM. DeLorean wanted his own two seater at Pontiac (The Banshee concept…..beautiful car), but GM axed it apparently because they thought that it would cut into Corvette sales way too much, though they did end up pretty much stealing the front end of the design for the ’68 Corvette.
The “Heritage Center” engine seen in pic #2…
I wonder what the engine’s ignition system theory was?
Each cam has a distributor cap located at its front, and presumably a rotor beneath. Also, a distributor body of sorts, complete with vacuum advance can, is located in the Vee. Apparently coil triggering and control of spark advance was going to take place at the “distributor” located front and center?
With that, apparently there was to be an accessory drive nestled in the Vee, and that would paddle the fuel-pump too? This is already getting overly complex.
Some lucky new owner apparently took charge of the Banshee, 2 1/2 years back:
Always considered it weird that pretty much in the entirety of post-war America, the greatest luxury cars were propelled by basically the same blubbering engine technology as some college kid’s stripper budget muscle car. Just my two cents coming from Europe and having historically had as much variety in the engines as in the cars themselves. Maybe someone can provide some socioeconomical insight.
Apologies for answering a question with a question, but from a socioeconomic standpoint, in the muscle car era, in some nirvana-of-engine-varietey, could a common college kid who applied himself just a bit above the norm own a “blubbering” IE “hot” muscle car? Or would he be riding a bus or train home, or at most be happy to own some archaic 20 hp basic transportation?
In a nutshell, it’s the power and economy of mass production that drove the sameness.
These were experimental engines I think, and probably needed to be aluminum to keep the weight reasonable. The aluminum V8 for the compact cars in the early 60’s was troublesome, so these engines were probably going to have some of the same problems. It would make sense that a production V12 would have been for Cadillac, but I think that what they may have done with it is very speculative. The FWD Eldorado seems like one possible idea, but a RWD sedan designed for the V12 priced well above the Fleetwood Sixty Special might have been a more sensible choice. Putting a V12 in the FWD Eldorado would have put more weight on the front I think, which would not have been good.
Yes, more of the longer block would have been ahead of the front axles. I doubt aluminum would have saved enough weight to compensate.
Cadillac needed an S class-fighting, high-dollar, big and powerful sedan after 1985, not a halo like Allante. Gas prices had fallen, and there were a lot more youngish people with money to burn after a dozen years of recession and stagflation at best. But they were 5 years behind the times and building cars for the world of 1980.
1. I find it no surprise that Cadillac engineers couldn’t meet the power-production goals.
2. Those exhaust manifolds look like they were resurrected for the Trailblazer/Envoy 4.2L inline six-popper.
3. Aluminum block, external headbolts–Cadillac made that mistake again on the hateful “HT4100” V-8 in late ’81 for the ’82 model year.
The guy that said this would have turned out like the V8-6-4, Olds Diesel, and Vega 2300 was probably correct.
Why was the Cadillac V12 only earmarked for FWD cars instead of a RWD Cadillac or even something like a Cadillac equivalent of the Opel KAD as mentioned in the following Curbside Classic Automotive Alter-History article below from a while ago?
It would have also allowed Cadillac to eventually consider a 60-degee V6 for a smaller model if desired.
In Karl Ludvigsen’s book on the V12, it seems that Mercedes-Benz around that period considered both V8 and V12 versions of what eventually became the Mercedes-Benz 600 “Pullman”.
Why was the Cadillac V12 only earmarked for FWD cars instead of a RWD Cadillac
The V12 was never earmarked for FWD at all; these were clearly designed for RWD.
If Cadillac wanted a V12, they could have just made an OHV iron block 60 degree with the same bore spacing as the Chevy small block (4.40 inches). Prestige, smoothness, cost savings over the aluminum block, lower hood than an OHC engine, possibility of a derivative V6. If at some point in the future they needed a lighter block, Cadillac probably could have gotten 500 cubic inches out of that arrangement. GM had a tendency to go a bridge too far, and then throw up their hands and go back to the OHV V8 and sulk.
Paul, new link, same story.
What about a die cast aluminum caddy engine? I worked as a co-op student in GM’s Central foundry division in Saginaw Michigan in the late 1970’s and one of the engineer’s (Frank Browning) was working on the next generation of caddy engine that was going to have aluminum cast block and heads. he was trying to work out the sealing of the wet liners and had a V-12 die cast aluminum block next to his drafting table. Of course I asked about it and he said it was a 1962 caddy prototype….that’s all I know. Any comments?