(first posted 1/20/2015, updated with more pictures) Most of the time, I love the fact that I’m a car guy in Michigan. Sure, our roads are terrible and our car insurance is among the most expensive in the nation, but we have car museums aplenty to keep the most devoted motorhead pacified during the drab winter months. My wife and I recently visited the R.E. Olds Museum in Lansing (for about the dozenth time), and came across this weird gem.
Yep, a V5 Diesel. I can’t even imagine what Oldsmobile was getting at with this oddity, but I was able to find a clue online in an old Popular Mechanics magazine from 1982. Apparently, the V5 was planned for use in small trucks and X-Cars. Can you imagine an Olds diesel in an X-Car? Both have about the most sullied reputations in the world of automobilia, but maybe by the 1984 model year, the bugs would have been worked out enough to make a go of it. With 70 horsepower, it certainly wouldn’t be going fast.
Even though I’m not the world’s most ardent fan of the vehicles surrounding them, GM’s engines from the late-’70s through the mid-80s fascinate me. They tried almost everything to rationalize and economize their engine lines, and concocted some truly weird methods of propulsion, including this 4.3 Oldsmobile Diesel V6, which was obviously created by hacking two cylinders from an Oldsmobile small-block.
We’ll save all those Chevy V6s created by lobbing two cylinders from Chevy small-blocks for a later time. For now, we can bask in the glory of one of man’s weirdest engines, a V5 Diesel.
Update (1-2021): On yet another visit to the R.E. Olds Museum this past August, I was able to take a better look at this oddball. I’ve added the new pictures below.
Here’s the V5 from the flywheel side.
There might have been some possibility of this engine making production, considering the thought given to the font on the manifold plenum.
Here’s a closer view of the injection pump.
This is another view of the passenger side, the bank with only two cylinders.
It looks like Oldsmobile either didn’t get around to making intake manifold end gaskets, or maybe they decided to emulate any number of garage mechanics and simply use RTV.
The title needs to be corrected. My first thoughts were a V-5?! What? How? I need to see internal specs, etc. etc. Upon reading, it became clear that this 4.3 is akin to the Chevy 4.3 ( or as has been said a 350 minus two cylinders!) Interesting item, though! 🙂
No, this is a V5. The third pic is the 4.3 V6.
Yes, it’s as weird as it sounds.
The 4.3 Diesel V6 is NOT a Chevy; it is a small-block Olds with two cylinders chopped off.
For years I falsely assumed all GM 350s were the same, for it made seemingly little sense to reinvent the wheel across divisions in a large corporation dedicated to that American god, Efficiency.
Now I conclude that Sloanism virtually guaranteed popular confusion over driveline pedigree. It was never a significant issue with Ford & Chrysler.
Yep, there were four 350s, four 400s (at one time, and Olds actually used two different bores and strokes between their 400s), and three 455s. If you count the Buick “400” Nailhead (that was actually a 401 underrepresented to fit into to GM’s tacit rule on intermediate displacement), there would be five 400s. Chevy actually labeled their 402 big-block a 400 in certain models.
No wonder things got so confusing in the ’70s when they started interchanging engines among divisions!
I was just a kid when the interchanging of engines between divisions begun, but recall the high emotions and class action law suits this caused. Probably only the mouthpieces made any money, though.
Nothing could equal the wrath of a Buick owner scorned by a Chevy engine!
the worst was at the tail end of the ’80s when GM was putting the Olds 307 in Caprice wagons but using the same VIN code as the Chevy 305. hated getting one of those in because I could count on getting the wrong part from the jobber about 75% of the time.
Hatman, it was the Olds owners that got the Chevy 350. The simple fact was that the Cutlass was the best selling car outstripping the Malibu sales. The Olds engine plant was running at full capacity and couldn’t meet demand. Meanwhile there was excess capacity at the Chevy plants since the Cutlass had taken a bite out of their market share. I never heard of a problem with Buick’s engine production failing to meet demand so if you ordered a Buick with the 350 you got a Buick 350.
Thank you sir, for setting me right…it was a while ago! And I love a proper Rocket 350.
what changed the underhood notification fron gender specific to general specs was a lady successful lawsuit to gm finding a chevy or buic engine in her cadillac
You all forget the Australian General Motors Holden V8 GMH it came in 253 cu , 308ci & later 304 cu Fuel Injection and 355 cu so another GM 5 litre and 5.7 litre. These motors had their own Aussie only design but later ones had chev trans pattern. Were produced from 1969 to 1999 the last ones had the same design intake as the ls engines years b4 ls motors did Look them up , 5litre and 5.7 motors came with this intake and roller cams in 1988 thm 700 trans.
It makes a little more sense if you consider that the different GM divisions had their own engine plants and for a long time were usually responsible for manufacturing their own engines. (There were a few cases of divisions buying engines from each other for certain applications, but until the late ’70s, those were the exception.) It’s not like there were a bunch of big corporate engine plants that were churning out four different 350s simultaneously.
The reality is that GM needed millions of engines and there was no way they could crank them out of a single plant, so it wasn’t that big of a deal to have the different divisions have their own engine with its own dedicated plant. Yes there were development costs involved but those were planned to be amortized over millions of units and many years. Once they had the design it wasn’t that much more to have the individual tooling built vs more copies of the same tooling. All was fine until the Cutlass became the best selling car in the land and they didn’t have Chevy like capacity at the Olds engine facility.
I remain convinced that the move to 350-400-455 displacements shared by multiple Divisions was the first quiet step towards eliminating Division-specific engines.
@ Jim: That was really by a different, earlier management generation, so I don’t think there was much connection. I think it was more that none of the individual divisions wanted to be bettered by the others — Buick didn’t want people to pick a Cutlass over a Skylark because the Oldsmobile 350 was bigger than a Buick 340. As for the 455s, I think GM may have made that the upper limit of nominal displacement for everyone but Cadillac; the Pontiac 455 was actually more like 457 cubic inches.
I’m with AUWM on this; the change to roughly unified engine sizes (350/400/455) came in around 1970; I really don’t think GM was anywhere near ready to seriously consider moving towards shared engines at that stage.
I’m not sure when that did happen; for that matter, I don’t think it was a carefully planned policy change but more being forced into it by the very rapid changes taking place as well as GM’s decline in market share.
The Chevy 454 was less than 455 cubic inches, while the Old 455 was 454.5+ cubic inches, so was designated as a 455. The Buick 455 had the shortest stroke, but was more than 455 and could have been rounded up to 456. The Pontiac had the longest stroke and was based on the 389 engine I think.
Oldsmobile owners did get all bent out of shape, mainly because Olds “forgot” to mention engine sources. Buick did not forget.
I bet there was some in fighting and eventually a corporate mandate that resulted in the unified advertised displacements among the GM brands. For example for the Pontiacs
350 is actually 355
428 is actually 427 (had to one up Chevy’s 427?)
455 is actually 456
I don’t think when they settled on the 350, 400, 454/455 displacements there was an intention to eventually consolidate to one engine. I think the consolidation was driven CAFE and consumer fuel economy demands, the EPA, and the loss of volume.
Hi DID NOT say it was a Chevy, he said it was akin to the Chevy 4.3, ie a V6 derived from a V8. Huge difference.
Hmmm. I wonder if Elliott edited his post or if I’m just an idiot. It could be either.
Sorry, this is what hasty early morning reading does to you! I repent for my sin & will be more attentive in the future!! 🙂
This engine, as well as the Olds 4.3 diesel, has NOTHING to do with the 4.3 Chevrolet V6. I knew a guy who had an ’84 Pontiac 6000 with the Olds 4.3 diesel. Total POS.
I have a hard time believing that a V5 ever made sense to an engineer. Aside from what most likely were challenging problems in solving vibration issues from the odd number of V configured cylinders (has there ever been a mass-produced odd numbered V engine?), the packaging advantage over a V6 must have been small.
Maybe this was an elaborate April Fool prank by Oldsmobile Division engineers that was leaked and mis-identified as real by the automotive press. 🙂
Honda made a few V3s for their motorcycles in the ’80s.
Honda’s V3 was a 2 stroke Grand Prix racing bike firing on every revolution. Pretty successful in the hands of Freddie Spencer, but they eventually went to a V4 for their last 2 stroke race bikes.
Honda had a four stroke V5 until 2002. I thought I remembered it and googled “honda V5 motorcycle”. Grand prix level racing.
Honda V5 Racing Motorcycle Engine info.
https://www.goodwood.com/grr/race/historic/2019/6/hondas-famous-five-the-motogp-five-cylinder-legend/
At some point VW offered a VR5 (yep, a VR6 minus a cylinder) in Europe. I don’t know how many they sold, but they were in series production.
The Acura Vigor had a 5-cylinder. I find it interesting that Acura offered a 4 (Integra), 5, (Vigor), and 6 (Legend) as a lineup.
The Vigor five cylinder was an inline five, not a Vee configuration.
I recall Audi and Volvo also offering straight fives in series produciton, and others may recall additional manufacturers building them as well.
The Volvo inline 5 was installed into Fords Focus as the hotrod model.
Mr. George, I find it even more interesting that Honda had the guts to put straight and flat sixes in motorcycles, but refused to make a V8 ( that I know of ) in any car. Especially after Lexus ate their lunch on their concept of a new luxury division.
Just had a brain fart and sent this to CC. Like Paul doesn’t have enough to do. I’ll try again.
Honda has made V8s and I do not know why they made none that wound up in a street vehicle. I believe that the early 250 grand prix bikes were 8s and I think V8s. What is perhaps more interesting, however, was that they did put V8s into four wheeled vehicles. If you consider indy vehicles a car this is what google had to say.
http://www.honda.com/newsandviews/article.aspx?id=6505-en
Sorry, you are right, I neglected to specify street cars….
Lee, Honda built the very radical oval-cylinder V8 NR500 GP bike in 1977, but never really sorted it out. I’m not aware of any 250 V8s; that’s too small, realistically, for a V8.
And yes, Honda made V8 racing engines for Indy.
Paul: You are correct. I think the 250 motor was a six. Probably some other sizes were as well. They were worked on a 50cc three that they never brought out so they weren’t afraid of much. The VR is very strange and don’t think I can call it a V8. 8 rods but only 4 pistons if I understand correctly. Moto Guzzi did have a v8 bike during that time frame. Honda felt that to use four strokes he needed more pistons than the competition.
Old timers disease. I hate it. The CRS syndrome.
yup, there’s one parked round the corner from me (green Passat wagon)
You are both right — the VW VR5 introduced in 1997 was a full production V5 engine, and Honda had a limited production V5 motorcycle race engine in 2002-06, as well as earlier two-stroke V3s in the 1980s.
GM would have been V5 pioneers if this engine had made it into production, though. The V5 prototype must be an artifact of the “we can do anything” era at GM — perhaps its last manifestation, having emerged in 1982.
Right-o. VW has actually had a couple mainstream production inline 5’s, first in the Eurovan, and most recently in the previous generation of the North American market Golf!
Oops, someone beat me to it while I was typing. The Volkswagen VR5 was a 15-degree, 2,324cc V-5 derived from the narrow-angle VR6. It was offered in the Passat and the various derivatives of the Golf IV platform (Golf, Bora, SEAT Toledo and Leon — I don’t remember if it was ever offered in the Skoda Octavia), making 150 hp DIN in 10-valve form and 170 hp for the later 20-valve version.
Which stlll brings the question “why?”. Cut off one cylinder from a gas engine? Wouldn’t it have been better to debore and/or destroke the VR6 if smaller displacement was needed?
No clue, other than perhaps someone at VAG trying it to see if it worked and deciding it was neat.
I dare say so it could share all the parts except the cylinder block & head (there is one head that covers both banks), and more importantly it could be made using the same machine tools. The vee angle is only 15 degrees.
The VR or “inline vee” just seems like a bad idea overall though because the exhaust ports of the first bank are so long, running past the second bank.
That makes a certain amount of sense, BUT it’s not like VAG really needed an additional engine in that realm: the VR5 wasn’t significantly more powerful than the four-cylinder 1.8T, which was also cheaper to own in some European markets. A normally aspirated 2.3 is maybe cheaper to manufacture than a turbocharged 1.8, but I can’t imagine the VR engines were all that terribly inexpensive to build either.
I remember drawing a picture of a car when I was a kid whose badging identified it as having a V9 engine. I guess I figured that if a V8 was good, a V9 would be even better. As I grew up, I came to understand that V-type engines only came with even numbers of cylinders, and to assume that it was probably not possible to really build a V9. After reading this post, though, I have to wonder if maybe I was on to something….
How about a W9–3 banks of 3 cylinders?
Or next a VR5 plus VR4?…or a W10 next?.. this could be fun…one day I will con a test drive of a Passat W8, the closest thing to a flat plane crank V8 I could walk into a dealer and get to drive…
The ’16 Shelby Mustang GT350 has a 5.2-liter flat crank V8, coming soon!
Yes!!
not likely
The future is fewer cylinders, not more.
They will be adding things like electric superchargers, direct injection, sparkless ignition gasoline engines, generators turned by turbos, crankshaft mounted electric-assist motors, throttleless engines with multi-air valve technology, instant start-stop, direct servo actuated valves, and 8-10 speed transmissions.
All these new advancements will reduce fuel consumption, increase power, reduce engine size requirements, and make lots of cylinders unnecessary and wasteful. 3 cylinders will be the norm for smaller cars in 5 years time. 4 cylinders will be the optional engine upgrade for larger cars.
Hello, I am a late arrival to this conversation. I found that Bentley Motor Division of Britain still produces a V-10 which is configured just like the Oldsmobile V-5. There is a u-tube showing the complete assembly of a Bentley engine; very impressive.
Bentley has a twelve cylinder engine, not a ten cylinder. The Bentley’s twelve cylinders are are arranged as a pair of VR6 engines on a single crankshaft. The effect is like four banks of three cylinders each. There are two cylinder heads.
BMW made a v5 diesel and I think it ws used in some of the smaller Lincoln cars in the 80’s
No they didn’t. They made in inline 6 diesel, as well as fours. The 6 was used by Lincoln too.
And since when is “built in Lansing” a special feature?
When the museum is located there. Municipal pride & all that.
I’d like to know how this engine got R&D funding. My guess is the bureaucratic imperative of “spend extra funds, or get less next year.”
What’s ironic to me about GM’s automotive Diesel Disasters is, there used to be TWO sibling divisions specializing in this sort of powerplant: Detroit Diesel & Electro-Motive. To be fair though, these were mostly 2-strokes, & oftentimes, corporate PR about “synergy” is all cant.
Couldn’t do it in this day and age but for the time a 2 stroke diesel seems like a reasonable idea. Worked well in subs, trains, and (IIRC) bigger vehicles. Don’t recall many stellar performances from the four strokes they did make.
I think the decline of 2-strokes is due to EPA pollution rules for trucks & locomotives. EMD (now independent of GM) never came up with a competitive 4-stroke; their current 710 is still 2-stroke.
I have a conspiratorial suspicion (with no evidential justification) that GE lobbied the EPA for tighter Diesel emission controls, knowing it would hurt EMD more than themselves. But I’m more certain that the SD50/645F fail damaged EMD’s reputation badly.
The real problem with 2 stroke diesels, for road use anyway, was the powerband. I remember driving a Screaming Jimmy 5 ton dump, and there was only about 800 rpm to work with. On the twisty, windy Island roads on which I was driving, it made shifting a real chore.
If you ever visit San Luis Obispo, CA; it is worth riding their 2-stoke shorty town duty buses for that joyful sound, before they go away.
Hmmmmmmmmmm? 2.5 ltr V5 diesel? Somehow I think it still would have been more refined than the Iron Duke in my 1982 Celebrity.
The thing that is curious to me is the 70 hp/111 lb. ft. – I expected a higher torque rating. The TBI Iron Duke back in 1982 made 90 hp and 120 lb. ft. of torque. I would have expected roughly 20 more lb ft of torque from the diesel than what it is rated.
I have seen ONE 4.3 ltr V6 diesel in the wild, in a Cutlass Ciera that was pulling a boat.
Dan, a naturally aspirated diesel engine almost inevitably makes less torque than a similar-sized gas engine. For instance, a 1979 Olds gas 350 made 275 lb.ft; the Olds 350 diesel made 205-220 lb ft (depending on version).
It’s a bit of a myth that diesels are torque monsters; they are with a turbo, but not without. Non turbo diesels are quite sluggish, generally speaking.
So the torque on that 2.5 V5 diesel is right in line as might be expected, a bit less than the 2.5 gas Iron Duke.
sluggish yes, but due to the higher bmep they will produce more torque with a given bore and stroke vs. a spark ignition engine. i can’t comment on this engine, but GM was never a 4 stroke diesel engine company (needed Isuzu for that) so this engine must have some combustion chamber and intake flaws to hamper it.
Show me an example of that: two similar sized engines, gas and diesel, both non-turbo, where the diesel makes more torque.
For instance: VW’s 1.6L Golf/Rabbit engines (1980s):
Diesel: 74 lb.ft.
Gas: 92 lb.ft.
the examples you site are converted spark ignition engines with relatively low compression ratios (for a diesel) because as you state the engines are not originally designed for the super high compressions. if i had the time i would have to find equivalent bore and stroke comparisons for a “real” diesel and a spark ignition engine to compare. i remember the Farmall MD started on gas and converted to diesel and had a paltry 13 or 14:1 CR so it wasn’t a powerhouse.
still doesn’t hold water. I had a 1984 F-250 with the 6.9 (420c.i.) IDI diesel. it had 175hp/315lb-ft, while the gas 400 was 136/310, and the 460 was 245/380.
It doesn’t matter if an engine is a “converted gas” engine or not; that makes no difference to their intrinsic functioning.
Here’s an example where the diesel engine was designed as a diesel from scratch, the IHI 6.9 L V8, as also used in Ford trucks. It made 315 ft.lbs.
The very similar sized Ford 429 gas V8 made a whopping 476 ft.lbs.
You’ve got it wrong; a diesel is more efficient, because it wrings more power out of a given amount of fuel, but a gasoline engine is able to burn more fuel at any given time, hence it makes more torque (and hp).
That’s why historically, truck diesel engines were so much larger in capacity, in order to make comparable torque and power. The turbo changed that equation, of course.
i should have said more torque for a given (low) rpm. diesel’s typically have long strokes and high bmep at low rpm therefore high torque at low rpm. they can’t rev because piston speed would become outrageous. the spark ignition engines cited derive their peak torque from high rpm’s. Now the military has recently built some high rpm diesel’s with incredible hp and torque, so that can be done as well, but typically it’s detrimental to longevity. so the axiom is diesel’s make more torque from a given displacement (not bore/stroke) but only true for low rpm. run that 429 ford at 2100 rpm and see what kind of torque you got, the binder is making peak torque at that or less.
Cant give you non turbo examples but my 406 Pug had the 2.1 TDI engine that was the companion to the 2.0 turbo petrol engine both pumped out the same torque 195ftlbs but the petrol put out 150hp and the diesel 110
OK; I decided to take you up on the “more torque at lower rpm” statement. Below are the torque and hp curves of the IHI/Ford 7.3 non-turbo diesel v8, and the similar-sized Ford 460 truck gas V8. As is very evident, the gas engine makes more torque than the diesel at both its peak as well as at the diesel’s peak. At 1650 rpm, the gas engine is making some 380-390 lb.ft.; the diesel is making 345 lb. ft.
As I said before: a diesel can squeeze more power out of a given amount of fuel, but the gas engine can burn more fuel at a given rpm, hence generate more torque.
Back in the 40s and 50s, truckers loved the big Hall Scott gasoline engine, because it made more torque than the Cummins and GMC/DD, but it also burned a whole lot more fuel in the process.
And the reason diesel engines can’t rev much above 4000 rpm, even racing ones as used in LeMans by Audi, is strictly because diesel burns slowly; there’s just no way a diesel can be made to rev high for that reason. It has nothing to do with rods and stroke and such.
Of course large truck engines rev more slowly than that because of their sheer size, but a gas engine that size wouldn’t rev any/much higher either. It’s a matter of scale.
i think i’ll pick up my good book and maybe say a prayer for personal enlightenment on you part Paul. I’m only human.
Paul, I don’t know if the previous comment was a compliment or not- but that explanation was brilliant. A simpleton such as myself understood; for example, I thought why Diesels didn’t rev much beyond 4k was due to their internal mass of reciprocating parts- but I do recall from long distant undergrad studies that while diesel has more kinetic energy, it burns slower than fuels such as methanol. That’s why we see methanol, not Diesel in many race cars. Rock on….
you’re entitled to your opinion but not your facts. Diesel fuel has a higher energy density than gas. it also combusts well at lower flame speed. you can optimize the bore/stroke to have a longer lever arm (long stroke) to exploit this at low rpm. I suspect the Binder truck engine (which Ford stopped using because it wasn’t a great design) was not optimized for torque with that torque/hp curve at such a high rpm. Consumers probably wouldn’t accept a 2100 rpm truck motor, plus all accessories are optimized for higher rpm. the transmissions have been designed for greater gear reduction and could not handle the torque at low rpm. there is no inevitability of gas’s higher torque than a similar size diesel. and because of diesel’s higher energy density it can handle much more high pressure air with forced induction and just kill a gas engine in torque production. and if i put a smiley at the end will you not be pissed? sheesh
You’re mixing up apples and oranges. We’re talking about apples to apples comparisons.Diesel engines have to be designed for the application they will be used in. No, a giant 2100 rpm Cummins engine is not going to work well in a pickup, never mind in a Jetta.
Smaller diesel engines are designed to be as efficient as technology allows; the competitive pressure to do so is huge.
The IHI/Ford 7.3 was designed by IHI to be a medium-duty truck engine, before Ford decided to use it. No, it was not designed to be used in a semi truck, road grader, locomotive or cargo ship.
If you’re saying that very large diesel engines have a higher thermal efficiency than a small diesel engine, I’m not going to argue that point. The most efficient IC engines in the world are the giant oil burners used in ships.
But that’s not what we started out talking about: that a gas engine will create more torque than a comparable sized diesel engine. And I’ve given you not opinions, but facts to verify the point.
Now it’s your turn. Instead of opinions, how about you show me the facts on a diesel engine that makes more torque than a comparable sized gas engine. That’s what my original comment was, and I’ve backed it up. You haven’t. You’ve just expressed opinions and generalities, but nothing to contradict my assertion (and facts).
What you fail to grasp is that because of the slow burning characteristics of diesel, there’s only so much diesel fuel that can be burned for a given amount of air. Trying to inject more will cause it to not all burn (run rich) and smoke. The only way to overcome that is with a turbo, which allows more air to be forced into the engine, thus a larger amount of diesel fuel too.
The reality is this: a naturally aspirated diesel engine is just not very powerful, and has a poor power-to-weight ratio. Which explains of course why there haven’t been any naturally aspirated diesels built in decades, for any application, except for some very cheap industrial engines.
A naturally aspirated diesel is essentially inefficient in terms of its weight and cost to build, and therefore is completely an uneconomic proposition. Which is why they don’t hardly exist anymore.
It’s much more efficient to build a smaller, lighter turbo diesel, and that is what essentially everyone does now. But that’s outside of the scope of our debate. But it explains why the naturally aspirated diesel went away: it’s intrinsically weak and lethargic, compared to a comparably-sized gas engine, as per my original comment.
plus we’re seeing the new generation of GTDI (gasoline, turbo direct injection) are torque monsters in their own right. 3.5 liter GTDI V6 in the F-150- 365hp, 420 lb-ft. 3.0 Ecodiesel in the Ram:240 hp, 420 lb-ft.
The much higher compression ratios of diesel engines plus the greater energy density of the fuel should tell us all very plainly that diesels have an advantage over gasoline for low RPM torque. Slower flame propagation speed should have zero effect at very low RPM.
However, this is a moot point in my opinion because we are talking about laboratory produced numbers. In the real world, what matters is SUSTAINED torque output. Gasoline engines run hot or overheat when forced to produce max torque for sustained periods. Diesel engines do not. There is less waste heat generated by a diesel engine as compared to a gasoline engine and this is why the diesel engine is less prone to overheating under heavy sustained loads.
Think about the waste heat subject now, and add this fact to the other 2 advantages of a diesel(compression ratio and energy dense fuel). Not only does a diesel generate more energy from combusting its fuel, it also transforms it into rotating mechanical energy more efficiently due to the higher compression ratio, AND it loses less energy in the form of waste heat. How on earth could a diesel NOT have more torque at very steady very low RPMs?
BTW there are probably more naturally aspirated diesels built today than ever before and not just for cheap industrial applications. Yanmar, Mahindra, Isuzu, and Kubota manufacture scores of small N.A. diesels for gensets, tractors, marine applications etc. These applications demand continuous torque production, not the intermittent torque requirement of autos. just look how long a gas engine lasts in a high performance boat (not very).
@ jz78817, I think BMW’s 3.0 liter (tri)turbo diesel in their M550d “outtorques” them all: 381 hp, 546 lb-ft.
BMEP for forced induction diesels is far superior to forced induction gas. the dispute was naturally aspirated.
these calculations fully scale down. 2100 rpm doesn’t mean big rig Cummins, hell even my little Kubota (900cc 3 cylinder) only winds up to around 3000. you could have an optimized for torque 7.0 L motor at 2100 rpm. the gas engine could never make that torque at 2100. but there were no automatic transmissions that would fit in a truck that could handle the torque at 2100 rpm so the engines were optimized for higher rpm and then they lose their sweet spot. they are as optimized as much as possible (however i worked for IH briefly and they are mostly engineered-by-marketing and accounting) at that rpm, but that is not where they could make the most torque.
What did you do at iH?
Insert cricket sound effects.
Sorry, I’m not buying it. You would not be able to generate any significant amount of more torque out of a non-turbo diesel, no matter what the bore/stroke.
Show me something, instead of just words. Show me a 7.3 L indirect-injected non-turbo diesel with a significant higher max torque than that IH motor. I’m waiting…..
sorry i have a wife and son and another life beyond the internet. BMEP for naturally aspirated gas engines is 120 to 150 psi, and diesel is 100 to 130. of course the gas BMEP is achieved at usually 3000 to 5000 rpm because of the flame speed being faster. so you can see there is overlap and you can optimize a long stroke low rpm diesel with a BMEP of say 130 psi and the gas engine at that same rpm would be under the 120 psi minimum because it’s out of the sweet spot. therefore a torquey low rpm diesel motor with a long life even though piston speeds may be up there because of the long stroke.
worked for IH construction equipment division for 3 years during IH financial crisis. they made a great tractor motor in the 466, the larger dozer motors and the truck motors not so much.
Paul
It depends…….
A naturally aspirated diesel can be very high on torque and have superior response to a turbo-diesel. All you need is enough volume and enough compression….
A good example was the Fuso 20-litre V-8 diesel. Mitsubishi built most of them turbo-free because they sought high torque straight off-idle with rapid tip-in “throttle response”. It worked as they expected and had the added benefit of a brilliant sound. They sure do sound good!
True, Ive been using a company pickup this week for getting various depots, a Toyota 3.0 4 cylinder diesel 4WD and its a gutless wonder ok on flat going but point it uphill and theres nothing but the same Hilux with a turbo diesel 3.0 or 2.8 pulls really well, forced induction and diesel go together like bacon and eggs.
I guess I will throw in my 2 cents worth. A diesel engine is more efficient because of the high compression and no throttle. The cylinder deactivation that some engines have (Chrysler 300C for example) get better fuel economy when in 4 cylinder mode because the throttle has to open more reducing pumping losses.
GM’s powertrain website shows a 2 liter turbo diesel that has 263 lb-ft of torque. There are a number of 2 liter turbo gas engines with various peak torque ratings, but in general they have about 260 lb-ft too. Turbocharging a diesel engine should make it more efficient. Turbocharging a gas engine requires a reduced compression ratio and will reduce efficiency.
My turbocharged ATS generally got about 29-30 MPG on trips to Rochester MN. I will be driving my 3.6 V6 CTS there soon. On my trip in the CTS to the west coast I averaged 27 MPG (more downhill from Flagstaff to home). The CTS’s highway rating is 3 MPG less than the ATS’s.
Turbo a diesel and you are going to need to reduce compression, same as for a gasoline engine. Reason is that the peak pressures and temperatures escalate with boost. Eventually you will get to the point where the engine is not going to survive. Pistons hole, rods bend, bearings fail, gaskets burst etc.
20 to1 compression in the turbo diesel in my road car, those engines dont come in NA diesel.
Too add to the above arguments, I googled BMEP and found on wiki that for non turbo engines there is a typical range for gas from 8.5 to 10.5 bar and a diesel is 7 to 9. Obviously one could design both engines to have the same BMEP.
Turbo gas engines have a range from 12.5 to 17 and diesels range from 14 to 18. Again it is possible to design both engines for the same BMEP.
The Olds 350 diesel V8 had a 22.5 : 1 compression. I think that the limiting factor in the torque was that the heads would blow off if more fuel were injected.
That is for max torque. You are not comparing torques at equal RPMs. If you do, I’m pretty sure the diesel will be the winner at lower RPMs.
John, did you not look at the two torque curves I posted in an earlier comment. The Ford gas 460 had significant more torque at 1650 rpm than the IH 7.3 diesel. Your argument doesn’t hold, unless you can show me actual examples.
And any engine can be designed to run at full torque continuously, gas or diesel. There used to be many big gasoline truck engines, etc. It’s just a matter of having the proper cooling system.
Of course a diesel is more efficient; that was never the point or issue in this discussion at all. The issue was that a naturally aspirated diesel engine typically produces less torque than a naturally aspirated gas engine. And no one has shown any evidence to the contrary, just generalized concepts that don’t actually translate into specific facts to support the contrary.
I did not look at your torque curves. I will. I will also look up the compression ratio of the IH 7.3
I have been thinking about this debate. I have decided that the difference in energy content of diesel vs gasoline is irrelevant to this debate. All that matters is the amount of air available for combustion of the fuel because the air is the limiting component in the fuel-air mixture. Diesel fuel has more BTUs per volume because it is a longer carbon chain molecule than is gasoline. But to oxidize that fuel you still need the same ratio of oxygen atoms to carbon atoms, therefore I will argue the ratio of oxygen atoms consumed per BTU heat energy output is the same with both fuels.(the presence of ethanol in gasoline may make this an incorrect argument though)
The air available for combustion is identical in the two engines since we are comparing identical engine displacement operating at identical RPMs. Therefore I believe the only advantage diesel has over gasoline is the compression ratio.
The compression ratio is all it needs however. If we consider two identical engines in every way except one has a 9 to 1 compression ratio and burns gasoline, while the other has roughly double that compression ratio and burns diesel, the diesel will win the torque contest. Theoretically of course. there are other details that will effect actual chemical energy to mechanical energy conversion.
fuel atomization
combustion efficiency
incomplete combustion
combustion chamber temperature
exhaust temperature
There is a concept called “stoichiometric ratio”. This is the theoretical amount of air required to combust all fuel molecules without any leftover oxygen molecules. In the real world, the stoichiometric ratio never works. Different fuels require different amounts of “excess air” to fully combust. I do not know how the excess air requirements differ between diesel and gasoline. I suppose it is possible that the excess air requirements of diesel are so much more greater than gasoline that it puts diesel at a disadvantage. Without better info I will choose to ignore this possibility because it does not seem likely to me..
The pumping loss issue I think it moot. I say this because in a contest of torque, both engines will be operating at full throttle. Therefore I give no advantage to diesel for its lack of a throttle.
Diesel will lose mechanical energy from its more energy hungry fuel delivery system. Injector pumps and fuel tank circulating pumps will consume more power than will a gasoline fuel pump. But I can’t believe this could be anywhere near as big a factor as having double the compression ratio. Besides, the gasoline engine must generate high voltage current for spark plugs while the diesel does not.
I think it is entirely possible, in fact likely, that diesel fuel combustion is a much trickier puzzle to master than is the gasoline puzzle, mainly because of the high pressure nozzles. My experience with power oil burners in industrial process high pressure boilers tells me this is so. I would bet dollars to doughnuts that there has been much more improvements in diesel than gasoline combustion in the last 50 years. Therefore I will hypothesize that comparisons between 40 year old engine designs are not representative of current reality.
it’s fundamentally about BMEP. that is the pressure on top of the piston and that’s what makes torque. it’s fundamental and you should probably read MIT Professor Charles Taylor’s 2 volumes on Internal Combustion Engine Theory, however, it is an engineering textbook filled with calculations. anything else is just peanut gallery commentary with no science behind it. what you would need as an example is a long stroke low rpm diesel motor and then convert it to gas to see how the diesel kills it in torque, but nobody would be so stupid as to build a gas motor like that. The old gasoline truck engines of yore were great but they didn’t last as long as the diesel’s.
If wiki is more or less correct, then for a diesel to have the same torque as a similar sized gas engine, the diesel would have to be at the upper end of BMEP while the gas engine would have to be at the low end. The Olds diesel V8 was kind of like a gas engine turned into a diesel, and the torque output is low.
However, most new diesels are turbocharged and have more torque than non-turbo gas engines. The diesel cycle is all about fuel efficiency, not torque. Truck engines are designed for torque, but fuel consumption is also important.
The basic problem with the above discussion is that diesel engines are designed for a particular service class and gas engines are also designed for a particular service class. Comparing them is probably pointless. What should be compared with what? The same size, or same power output, same fuel consumption…?
sort of my point. difficult to compare engines and especially gas engines converted to diesel, they were optimized for gas and therefore make poor diesel configurations with the wrong bore/stroke and probably head design. the example above is not good because the Navistar powerstroke was not a great engine and forced Ford to develop their own. the fundamental argument is that naturally aspirated diesels inevitably make less torque than similar sized gas engines. that statement is not true.
i think Paul conceded that turbo diesels make more torque than turbo gas engines. he’s just a zealot about the other issue for some reason.
Comparing gas to diesel turbo engines is utterly futile, because you can dial in any amount of torque you want depending on the boost level. Which is why chip-tuned turbo engines (gas or diesel) make insane amounts of power.
As the wiki numbers show, gas engines generally have higher BMEP numbers, which of course perfectly supports my point. Why are we still even arguing this.
There is an equation online that allowed me to compute the Olds diesel bmep for the 78 engine (220 lb-ft) which turns out to be 6.5 bar. This is below the usual range.
I finally found a gasoline engine that was also made into a diesel that was designed for sustained torque. There would never be a car like this, and not even trucks, but it is an engineered engine. John Deere model 720. Nebraska test no. 605. 6″ x 6.375″ 360 c.i. gasoline 50.3 hp @ 1125 rpm, 260.6 ft.lb. @ 788 rpm. Test No. 594 6.125″ x 6.375″ 376 c.in. diesel 56.66 hp @ 1125 rpm, 306.8 ft.lb. @ 731 rpm. if you factor up the gas tractors peak torque by 4% due to the displacement disadvantage, it still only comes up to 272 ft. lb. So the diesel won pretty handily and it did it at a lower rpm. the hp was measured at the belt pully, so if you know 2 cylinder JD’s, it only had to go thru the clutch so that was crank hp. So this was truly an engine that was well engineered and it was made into fine gas and diesel versions, and the gas tractor gets left in the barn when it comes to naturally aspirated torque. never mind the record setting fuel economy on this beloved Johnny Popper. not mine in the photo, i do have a brother with a gas 630. go to a county fair tractor pull sometime and listen to one of these lug, far different experience than 2 stroke Jimmy for sure but impressive.
Congratulations on finding one example. But the problem with it is that these engines are antiques; more specifically, the JD twin design goes back to the early 20s, and the diesel came out some 15 years later or so.
The point being is that the JD gas engine did not have anything approaching a modern, well-breathing head design. The diesel was a newer design, and undoubtedly more optimized.
I’m not trying to split fine hairs here, but the technology was changing rapidly back then. My whole point here is that modern gas engines breathe better and can burn more fuel, even at low rpm than a diesel, hence they generally have a higher BBMEP and better torque.
and diesel’s haven’t improved since 1956 either? you don’t understand the fundamentals here but it’s one of those things. you own the ball and bat (website) so you play by your rules but it’s plain to others who have posted. i’ll just be content with my University of Illinois mechanical engineering degree and 36 years of professional engineering experience. you fall back on your website. i’ve seen you beat down other people before, but it is viewed as mean spirited and desperate. i knew i would never convince you Paul, but others know the truth and that was my purpose. Good day
I’m not trying to beat down anybody, and I’m perfectly happy to change my mind in the face of convincing facts. Keep one thing in mind, the original comment was about the apparent low torque of that V5. And I commented that automotive naturally aspirated diesel engines almost inevitable have less torque than comparable gas ones. The subject of this debate is not about industrial engines or antique tractors. It’s about automobile engines.
But you chose to drastically widen the discussion, and not sticking to the original one.
I and others have shown numerous examples of automotive gas engines having more torque than comparable diesel engines. I even found a truck engine to compare although that was outside of the primary issue.
You keep talking about optimal ultra-long stroke slow speed engines, as might well be used in a setting outside of an automobile. And very early on, I conceded that under certain design parameters, you might be right.
But you are not right when it comes to automotive engines, and ones used in mid-sized trucks and such. Injecting theoretical aspects and engineering principles doesn’t mean anything when we’re talking about real actual engines as they were built: the gas ones had more torque than the diesel ones.
But in the face of all that evidence, about real engines built by engineers who knew, given the times, how to build the best automotive diesel engines (Mercedes, VW, etc.), you just won’t accept that fact.
We’re not talking about engineering principles; we’re comparing the actual torque output of actual engines that were built back then. And in every case and example, the gas engines had more torque.
So the problem is not me beating on you, it’s the facts I and other have presented that’s beating on you. And it’s your utter unwillingness to concede that the debate, as framed initially, has not gone your way, because you want to argue on engineering principles that don’t really directly apply to the debate. If it was a different debate, maybe so, but not this one. Sorry.
BlueOvalDave
So what?
Given two engines, both of the same displacement, both naturally aspirated, both at the same rpm and both with the same volumetric efficiency, the gasoline engine WILL make more torque than the diesel. Fact.
The reason is that the diesel engine burns approximately 80% of the air it ingests. There is not much you can do to get past this well known limitation of the diesel engine. Inject more fuel per injector squirt in the attempt to obtain more torque (by consuming more of the ingested air) and you might get a tiny bit more torque but you’ll also get more and more smoke. Holy rolling coal! All this signifies is that most of the extra fuel you are chucking in is only partly burning and ~20% of the air is not doing anything at all. Meanwhile the gasoline engine burns around 99% of its ingested air. You just aint going to get around that.
Size for size the gasoline engine will make the better torque given the restrictions I mentioned at the start of my post. Now were you to expand the diesel by, say 50%, well then it would be a different story!
Cheers!
wild west I’m not suprised to hear that the Olds BMEP was sub-par. GM never did know how to design a 4 stroke diesel, that had to bring in Isuzu to design their truck motor today.
Except that you probably need gross brake torque rather than net.
Head gasket problems where common on all these v8 diesels right through to the 6.5
My experience with my 78 Olds Diesel was that once you got it up to cruising speed (it did not accelerate quickly) was that hills did not seem to bother it at all, although on high altitude mountain grades it was slow.
In my 1979 World Cars book I found a few non turbo diesels in the German market:
VW – 1471 cc diesel – 50 hp – 59 lb-ft torque.
VW – 1457 cc gas – 70 hp – 81 lb-ft
300D – 5 cylinders 3000cc – 80 hp -127 lb-ft
gas engines are 6 cylinders 2500 cc -129 hp -145 lb-ft
These engines were designed in a common era and so seem to comfirm PN’s point that the gas engines have more torque, at least in production engines.
Audi has a 5 cyl diesel too 121 CID 70 hp : 91 lb-ft
gas 4 cyl 97 CID 85 hp : 90 lb-ft
Wow. What could the benefit of this possibly have been? Certainly not engine physical size, or expense to manufacture. This has CAFE written all over it. “Smithers, I want something to squeeze every last tenth of an MPG out of this Delta 88 for those tests at EPA.”
In their defense, the five cylinder engine seemed to be a minor thing in the early 8os, with both Mercedes and Audi fielding one, IIRC. However, those were inline engines which would not have the horrid balance issues that a V configuration would bring. But I suppose that with enough balance shafts, you can make anything run smoothly, more or less.
RE: in-line – Mercedes, Audi, and later Volvo, and also VW, all in-line except VW which had inline as well as VR5. The Mercedes 5’s were relatively common in Europe, Audi used them both with turbo and without between the late 70’s all the way up until the mid-90’s and now has one again in at least some versions of the TT. Volvo used a 5 in the 850/S60/V70 lineup and VW until last year had a 5 in some versions of the Jetta and Passat here in the US. I’m sure I am forgetting some (or many) but there are a lot of them. Oh, GM even had one in the Colorado/Canyon truck if I am not mistaken, but again an in-line.
The few German straight 5’s if driven were surprisingly good. I especially liked VW’s 2.5.
Ford has a 5 pot diesel in the Thai developed Ranger Ive driven a few they go quite well and are very popular here es[ecially for towing caravans and boats which needs tprque not hp.
I agree, GM was looking for any PR that said “We are saving fuel nowadays”. I remember the V5 in buff book ‘coming soon’ articles and thinking the same ‘wtf’.
When GM killed the diesels, I thought they would make a comeback, but then brand loyalty died then, too. And I dont blame them!
What I find unforgivable is what General Motors did to ruin the diesel engine’s reputation as a reliable engine for cars. 🙁
While I think GM soiled their reputation for building diesel cars, Mercedes diesel reputation continued on without any side effects I think.
GM might have fixed the diesel’s if the EPA had not been so intent on imposing emission standards for diesels. The real problem with the Olds V8 diesel was trying to make it as cheap as possible. This was the basic problem with the Pontiac Fiero too.
I agree. It’s unforgivable, though, that there aren’t many cars and light trucks with diesel engines. I can think of many cars that would benefit from a diesel engine. What good is cheap if the quality suffers as a result? That’s the problem with American cars of the 1970s and 80s.
What is not clear to me is who is at fault, GM’s upper management or Oldsmobile’s manager. Obviously the various divisions thought they had to propose things as cheaply as possible, and probably upper management encouraged that idea. However I think most of the problem with Olds diesel was Olds management.
Who’s at fault is irrelevant. Management is not the ones doing the work at building the engines. What matters is how well the workers do the job with what they have to work with. If the materiel is of acceptable quality, excellent! If it’s not, too bad. They wouldn’t be able to fix the problem if they had the time.
As a lay person to engineering, this is all wrong; but who I’m I to question the organization of many tentacles that also made the V864, messesd up early TH O/D light duty transmissions, 4100 V8 for their flagship division, even for full sized models, wonky display electronics for their flagshipship sports car, on and on. All during this time period.
I specialize(d) in human resources as a military NCO; now retired, in a different field. April Fools jokes are great for morale. I’m all for them, as long as no one gets hurt physically or emotionally. However, I hope this isn’t one- it shows way too much free time, unless they could whip out such prototypes in an afternoon.
I did some googling, what I found is that it had the injection pump in the place where the “missing” cylinder is supposed to go.
It was supposed to be used as an optional engine in the X-cars and small trucks.
https://books.google.com.pr/books?id=f9kDAAAAMBAJ&pg=PA20&lpg=PA20&dq=v5+diesel+oldsmobile+engine&source=bl&ots=fsZnUnC_ua&sig=pulKvdtWqe9gvn38Q6rk2p5dit0&hl=en&sa=X&ei=cXO-VNz0MLiHsQSXkYGQDA&ved=0CDsQ6AEwCQ
http://www.onedirt.com/news/ever-heard-of-a-v5-diesel-engine-olds-made-one-in-83/
Most of the sites that I found have basically the same information.
Thanks for your research- now it makes some sense. Looks like a good place for a diesel fuel pump metering system to be out of the way, especially for a small car. I do agree with Principal Dan: I found the torque surprisingly puny. Were turbo 4 Diesels too costly to even consider?
The VR5 and V3 make sense for their respective situations, and were likely well designed. Though the V5 would have run like a V6 with a plug wire pulled.
I’m not against GM producing a diesel engine for cars. Unfortunately, what we got by the late 70s, early 80s, was a piece of junk that would fall apart on itself, and totally soured diesel engine’s reputation for good quality, from which diesel has yet to recover. If that isn’t fucked up, I don’t know what is. I like diesel engines for their durability, their fuel economy, and their reliability. But if General Motors isn’t going to build their engines the way they’re supposed to be built, or their cars to withstand the compression diesel engines are known for, then perhaps they had no business even attempting to build diesel engines for cars.
The 4.3 diesel V6 was not simply the 5.7 with two cylinders lopped off. It was essentially a completely new design with its own (more robust) head bolt pattern compared to the V8. the V6 had each cylinder surrounded by 6 bolts instead of 4. If the engine hadn’t been so gutless and hadn’t had its rep tarnished by the 5.7 it would probably have been a durable engine.
Do you know if the 350 Diesel eventually received similar updates? It does seem that the 4.3 and the 5.7 share bore and stroke, but I must assume that the 350 was updated for Diesel duty…at least that’s what I’ve always heard. I’ve never had one apart.
No. The block was similar to the gas Olds 350 (not the same, nor was it a mildly modified block; it was quite different) because GM wanted to be able to use as much of the production tooling from the gas engine as they could. There was no gas Olds 4.3 V6 to share tooling with so they weren’t under that constraint.
jz78817 is correct. The Olds 350 diesel still had the same head bolt pattern as the 350 gas engine right to the end, so they could use the same tooling to manufacture it. For the 1981-and-up 350 diesel engines, they tapped the block deeper to use longer head bolts. They should’ve really used larger diameter head bolts or more of them (like on the V6 diesel) but they didn’t.
The Olds diesel 350 block was very much based on their gas 350. It used essentially the same block, but modified for heavier duty use, with more metal, stronger mains, etc. It’s not exactly the same as the gas 350 block, but a direct development of it. Which is why the diesel 350 block is often used by racers for hi-po gas engines; all the gas engine parts fit.
It didn’t have enough head bolts, and/or the bolts used weren’t strong enough and stretched. That is the main problem with the Olds diesel engine. The other issues had to do with water in the fuel, lack of proper sediment control, etc.. The basic block and internal parts were fine; it was just a problem of keeping the heads on, given the much higher compression.
The 4.3 V6 was an adaptation of the 350, but with further refinement and changes to allow it to be used in a transverse layout, and an extra head bolt per cylinder. it was supposed to have fixed the problems of the 350, and was better in terms of keeping its heads on.
Update: the early D block version of the 350 had internal issues too, since the bolts holding the crank caps did not have enough meat where they went into the block, causing crankshaft failures. There were other issues too. The D series (first) was problematic all the way around. The later DX series fixed some/most of these issues.
This engine was not properly developed, and obviously rushed into production without being fleshed out. A common GM Deadly Sin.
As for why the 2 stroke diesels went away, it was a two-fold thing. First is that while few could run with it on level ground a Detroit could smell a hill a mile away and it was scared of them. A Cummins or Cat would flatten those hills right out.
Second was GM being GM and penny-pinching the product into an unreliable mess so that by the end of the Seventies Detroit Diesel had about as bad a rep as an Olds diesel. Detroit Diesel used to own the market in the US but by the Eighties it was a pale shadow of what it had been.
Over the last few months, I’ve become fascinated with those old 2-stroke Detroit Diesels. I believe Kettering himself came up with the idea (which is nothing like a 2-stroke gas engine, by the way).
Yes, he did. I did a post on the birth of the DD here: https://www.curbsideclassic.com/trackside-classic/the-birth-of-the-gmemd-two-stroke-diesel-engine-very-well-ket-we-are-now-in-the-diesel-engine-business-excerpts-from-my-years-with-gm-by-alfred-sloan/
the Chrysler EBDI (external breathing direct injection) was very similar to the Detroit Diesel design, except in gas engine form. it was closed-crankcase with a blower for aspiration. the EBDI was supposed to be the showcase engine for the Neon when it launched, but still couldn’t meet some emissions limits.
What a strange, strange motor. If the injection pump is where the 6th cylinder would have gone…was there nowhere else to put it? I’m still kind of failing to see the rationale here. Tight engine bays? Pure pursuit of MPG (but in that case why not use a slightly larger-bore or higher-compression I4?) Hmmm….
I’ve heard of inline 5 engines, inline 6 engines, V6 engines, inline 8 engines, V8 engines. But I’ve never heard of a V5 engine before.
I’m wondering if the Popular Mechanics article is the same one I saw. According to the article I saw, GM was looking into a series of modular engines: same bore/stroke, same pistons, same rods, same valves, same lifters, same valve springs. The plan was for an I3, a V4, a V5 and a V6. In keeping with the modular concept, there were 2 distinct cylinder heads: one covering 2 cylinders, one covering 3.
that actually was the way the old two-stroke Detroit Diesels were, especially the series 71. the -71 could be had in configurations of 1, 2, 3, 4, 6, V6, V8, V12, V16, and V24 cylinders. all used the same piston/rod/sleeve combination, and the bigger engines used combinations of parts from the smaller ones. want to build a V12? Use a V12 block, install 12 of the -71 series pistons/rods/liners, use two 6-71 heads and two 6-71 blowers. V16? cast a V16 block, use four 8V71 cylinder heads and two 8V71 blowers.
I think I read that same article about GM planning a line of modular oddball engines. They were all awful Iron Duke-type pushrod beasts. There was a photo of a V-5 but I can’t remember if it was otto or diesel.
JZ I rebuild a Detroit Diesel 6-71 in an occupational program so I could graduate high school. If I recall the heads were three 2-cyl units.I knew there were 2-71 engines but don’t remember anything in the shop docs about a 1-cyl 1-71.
Now that I think of it, the article I read was in Road & Track in the early 80s, and nothing was said about the engines being other than Otto. Pushrod beasts, yes. There was a photo of an engine, but I forget the number of cylinders.
I remember when we had been joked at a barstool (about 20 years ago) with a pal of mine about cars and about a “non-existing” oddities like the “V5” engine… That “joke” was already a reality at that time… Thanks for posting this interesting article.
V5?!?!!? Now that’s a weirdo plant if Ive ever seen one. Inline 5’s can be pretty nice, Audi’s turbo version in particular. Ive never driven one, but Id love a 6spd manual TT-RS with that motor….
Doomed to failure without even having to think about it. V5? Really?
The thing that bugs me about this V5 is the firing order and harmonics. Examining how GM made the 3.8 Buick an even fire engine shows how much effort it takes to make a “non-natural” engine design more inherently smooth. Now, on an inline 5, firing is spaced out every 144 degrees, but how would that work out on a 90* (or is it 60*? I guess I never noticed) V5 engine?
It seems like it would require some real thought! There would be little experience with this engine architecture, so you’d be pretty much blazing a trail!
Perhaps that explains why it’s only a prototype 🙂
My neighbor had one of those rare 4.3 diesels. In a Buick Century. Engine worked OK; it was the huge starter motor working against the 17 to 1 compression ratio that trashed the flex plate. Buick did a customer goodwill repair and then he sold it….
When I was a kid and those “Electra 380s” came out in ’85, I always wanted to see an “Electra 430,” as advertised in the brochure. Never did, they were all 380s in my area. I don’t even remember any Electra 300s around. I think in ’86 (or ’87?) the 3.8 became the only engine in Electras.
From what I understand, Olds was always the “innovative” division of GM. A V-5 engine? I don`t think so.
A V5 engine seems like a silly idea. A straight 5 make some sense. A well designed turbocharged 4 would have been a good plan.
I remember reading an article in Collectible Automobile on this engine many years ago,,,,,from what i can recollect the V5 design was driven due to space and packaging limitations in the transverse application for the X cars. The problems associated with the 350 diesel and subsequent bad press, essentially sank any interest in moving forward with the V5.
It is curious GM looked a 2.5-litre displacement for the Oldsmobile V5 diesel, given a hypothetical V5 version of the 260 / 4269cc Oldsmobile V8 Diesel roughly displaces around 2668cc. Unless GM were using the V5 diesel as a test-bed of sorts for more Euro-sized V6/V8 versions of the Oldsmobile diesel displacing around 3-4-litres.
Unsure about the viability of a V5 diesel, though it is a pity GM did not resolve the issues of the Oldsmobile V6/V8 Diesels so they could be quickly upgraded to turbodiesels.
One could also argue it would have been cheaper for GM to instead base the Oldsmobile V6/V8 diesel and Pontiac V8 Turbo (plus McKellar 421 Pontiac SOHC V8) engines around the Chevrolet Small-Block V8 (together with properly developed versions of the GM 122 4-cylinder and GM 90-degree V6 units along with production all-alloy variants derived from all-alloy Vega V8) whilst lower-displacement versions are modified to utilize the bore/stroke of the Buick V6 to be applied on alternate versions of the GM 122, GM 90-degree and Chevrolet Small-Block V8.
My bad, the GM 122 was derived from the 60-degree V6 not the 90-degree V6.
Essentially envisioned a related properly developed 4-cylinder engine derived from both the 90-degree V6 and Chevrolet Small-Block V8, a better conceived Pontiac Trophy 4 engine drawing inspiring from the GM 122, Chevrolet 2300 and Iron Duke engines (along with the earlier Chevrolet 153 4-cylinder).
Are the cylinders a uniform size?
Not too many years ago, GM was developing an HCCI engine that was part-time compression and part spark ignition and supposedly more efficient. Wonder why it went the way of the Wankel.
I’m on my second inline-5 gas Volvo. When someone asks me about such an odd engine, I’ll point them here and say “You ain’t seen nothin’ yet”.
The use of silicone to put the engine together was not unusual for GM. GM engines used a sealant of some kind rather than a gasket in many places back then. Silicone and anaerobic sealants.
As far as the V5 goes somebody somewhere must have the “dirt” on why this engine disappeared. That engine looks like a prototype ready for production.
I’m not sure why anybody thought this engine was ever going to be a good idea. The Iron Duke 4 cylinder was actually a better engine, and that’s saying a lot, given all the problems that engine had. It had more HP and torque, and gave good fuel economy, for the time. It had it’s own problems, where smoothness was concerned, but it was at least more balanced than a V5 would have been.
Such a waste. This needs to go into somebodies Crosley ratrod.