Worst Engines of All Time: GM 2.5L Iron Duke Follow Up

A follow up video to my previous video on GM's 2.5L Iron Duke, addressing key viewer commentary. This engine was used in the GM A, X, N, F, and P (Fiero) cars as well as S-10 trucks.
See original video here:
• Worst Engines of All T...

[@joshuagibson2520]

Some of the best car content anywhere. I'm a late 70s Z28 guy, but I can only take so much Camaro and Mustang content. What a huge breath of fresh air thus channel is.

[@mattmalone524]

Here is the good thing tho. The Mustang now is the best selling sports car in the world and the best selling in Germany for the last 3 years. Considering is this the country that makes the Porsche,BMW, Mercedes, and Audi, that's quite a feat. Now the Corvette has a 32v DOHC engine so that is also going to be very popular in those countries as well. America builds the best V8 engines period and the GM 3800V6 Gen 2 is one of the top five best V6 engine of all time.

[@SuPerbMusiCFan]

@@mattmalone524 and this relates to the original comment how exactly?

[@mattmalone524]

@@SuPerbMusiCFan It does relate in my estimation. American cars seeem get a bad rap and I always come to their defense. I realize he wasn't knocking American cars but casual readers that read these comments may and the fact that we have cars to compete with German exotics on their own turf, I think that is remarkable.

[@codyluka8355]

@Shawn 🏴‍☠️ Stafford I agree, it was pretty funny that the Iron Duke was the base engine in the 3rd Gen Camaro and Firebird from 1982-1985. I did drive a friend's '87 Firebird that had the 2.8 V6 in it once and it was pretty enemic. The Iron Duke models had to have been absolutely hopeless.

[@1Smooth___Operator]

@@mattmalone524 no lies detected

[@kcindc5539]

I got to witness someone getting “Iron Duke’d” first hand. My grandpa wrecked his positively ethereal 283-powered pale yellow ‘67 Chevelle (sad day for me as I was 15 and wanted that car badly) and replaced it with (you guessed it) an Iron Duke-powered ‘81Citation that shook like a nervous chihuahua and was painted what can best be described as “diarrhea brown”. Being a Florida car, idling with the car in Drive and the A/C on is a punishment I wouldn’t wish on anyone.

[@drippinglass]

Was the Chevelle a 2 door?

[@kcindc5539]

@@drippinglass nope. Four door. Black vinyl bench seat interior.

[@pcno2832]

The AC probably made much of the difference; my father's '81 Citation was the last car he bought without it and the shaking didn't leave nearly the same impression on me. The fact that the heat trickled all summer (a chronic GM problem during those years, best solved with a manual summer cutoff valve) bothered me a lot more.

[@michaelbenardo5695]

Richening the idle mixture smooths out the idle quite a bit. You just have to remember how much you turned that screw out, so you can put it back when it is time for a smog check.

[@jeffrobodine8579]

GM never liked flipping the bill for balance shafts.

[@calbob750]

I owned a 1986 Olds Cutlass Ciera with the “Iron Duke”. A gutless engine, but 32 MPG highway.

[@firehawk6188]

You hadn't experienced an 82' Cavalier with the 1.8L 2bbl engine + TALL geared 4 speed manual. The absolute slowest car I ever owned but would go FOREVER on a tank of fuel it seemed like! Jumping in my dad's 80' Citation with the same 4 speed made it feel like a rocket ship. My buddies mother bought an 82' Camaro with a 4 speed! Awww heck yea!!! Until we drove it. 2.5L iron duke. WOW

[@michaelbenardo5695]

@@firehawk6188 While it was no rocket, it WAS stronger than foreign-style 4 cylinders.

[@ohioalphornmusicalsawman2474]

My Dad had a 2.8 v6 powered '88 Celebrity wagon that got 30 on the highway, and was far quieter,,smoother and stronger than the "buzz bomb" 2.5 liter noisemaker

[@robertv2787]

In 1982 I was a test engineer at GM's Milford Proving Ground - what a great job! Anyways we ran tests comparing the 4 '82 A car engines for acceleration and fuel economy. We tested a Chevy with the 2.8L-V6, a Buick with the 3.0L-V6, a Pontiac with the 2.5L Iron Duke, and an Olds with the 4.3L-V6 Diesel. The 2.8 and 3.0 were carbureted, the 2.5L had TBI fuel injection, and the 4.3 was indirect injection diesel. All had the 3 speed THM125 automatic. The results were, the 2.8L was the quickest (0-60 about 12 sec I think) and got better economy than the 3.0. The 2.5 and the 4.3 were similar, with the 4.3 diesel being a bit quicker, and the 2.5L getting a little better economy. So the 3.0

[@robertv2787]

sorry - so the 3.0 and the 4.3 did not make much sense and did not last very long in the lineup.

[@dennissmith9577]

Do you have any stories of working with GM's wonderful Cross-Fire fuel injection during that time?

[@robertv2787]

​@@dennissmith9577 Sorry Dennis, no, other than remembering that it did not perform any better than the Qjets.

[@Sheisthedevilyouknowwho-ft9we]

Always good to hear from guys who worked at GM. You got the inside knowledge 🙂

[@Sam_Eassa]

My first new car was a 1978 Pontiac Sunbird with the Iron Duke. I was so disgusted by the lack of power that I traded it one year later for a new 1979 6.6 Litre Trans Am which I still have in my garage today. The interesting point is that due to the gas crisis of 1979, I ended up paying less than $2000 for the trade. People were paying premium for the 4-cylinders and no one wanted the T/As in those days.

[@michaelbenardo5695]

I am not a sporty-car lover, (too old, need something easy to get in and out of), but a Trans Am sure would be fun today!

[@jeffrobodine8579]

You made a good investment on that Trans Am.

[@Sam_Eassa]

@@jeffrobodine8579 I believe so. It's a WS-6 and I kept it all stock and have only 50K miles on the odometer. I keep it garaged and only drive it around 100 miles a year. Glad I cut my losses with that Sunbird.

[@drippinglass]

I think you are mistaken. Pontiac sold 116,000 Trans Ams in 1979... during the gas shortage. To put that into perspective... that was just Trans Ams, not including Formulas, Espirts, and Firebirds... Chrysler didn’t sell that many E body Barracudas in 5 model years.

[@life_of_riley88]

A high school friend of mine had a 1970 Hemi Cuda in his garage that his dad had bought in 1980 for like $300. No one wanted them, and it's worth an absolute fortune today.

[@johntierno546]

A noisy, crude, rough and weak engine that gave no driving enjoyment. Sounded like it was full of marbles. I don't care how long it runs for, that just means all the more suffering with it. An engine that encouraged people to check out the competition. Definitely one of the worst ever. Your analysis is correct Adam. And by the way I had one in a Citation that ended with a rod out the front of the block and oil on the hot exhaust which ignited and I gladly let it burn. It was over. Finally.

[@Sheisthedevilyouknowwho-ft9we]

301, runs extremely smooth. Half a 301, not so much 😢

[@zythr9999]

😆

[@davidpowell3347]

Was she over the "redline" when she blew?

[@SCREECHTRUMPET1]

My experience was that a 2.5L Iron Duke with a 5-speed manual transmission was much better than one with a 3-speed automatic. In terms of smoother idle, better performance, and better fuel economy, it was evident that the 5-speed manual transmission helped.

[@bnjoo]

I'm sure the flywheel helped them, as Adam failed to mention.

[@evoblade2000]

When I was 16, my father gave me 1979 pontiac gran le mans. It was a smooth running V8 car, but it did have some issues. A year or two later he traded for it a 1990 chevy celebrity with an Iron Duke. That car ran rough as a cob, was loud (due to a developing exhaust leak), and probably made 50 hp. It could not maintain speed on hills no matter how early or how hard you mashed the gas. I have never had such contempt for a car. I used to rip the shifter around while i was driving in the hopes that the transmission would break, but it stubbornly ignored me, like a truculent mule. I did not miss that car when it was replaced. Celebrity I hope you slowly rusted away in a junk yard and got melted down to make a sewer pipe.

[@RareClassicCars]

That’s pretty funny.

[@noscwoh1]

The only thing worse than a car you love that breaks (ahem, Northstar) is a car you hate that won't. 😂

[@satchelh]

All good points mentioned here. I remember the disappointment and even maybe disgust people had for the cars of this time based on expectations. Also, reliability isn't immediately realized, it grows with time and miles.

[@amhicks21]

I went from being used to driving a 1986 buick century with the 2.5 to driving a 1991 caprice with the 305. Over 20 years later i still remember how blown away I was by how smooth and quiet the 305 was compared to the iron duke.

[@michaelbenardo5695]

4 cylinders have never been known for smoothness. 8 cylinders, whether inline or V, are super smooth.

[@amhicks21]

@@michaelbenardo5695 true, but putting such a clattery 4 cylinder without even a balance shaft in an otherwise very smooth driving and comfortable sedan just doesnt fit. They shouldve stuck with LLV's and S10's in my opinion.

[@jeffrobodine8579]

@@amhicks21 My 1979 Toyota Celica had a honey of a 20R 4 cylinder motor in it. Much smoother than my 1983 Chevy Camaro with the 2.5 Iron Duke I once had.

[@jeffreysproul9110]

@@michaelbenardo5695 Not all 4 cylinders are rough. Honda 4 cylinders are very smooth especially with a Honda manual. Also the 2.2 4 cylinder in my 99 Chevy S-10 with a 5 speed manual was very quiet and smooth. The 2.4 4 cylinder in my hybrid 2012 Buick Lacrosse was very smooth. The technology has vastly improved and with the addition of EFI the 4 cylinders have become much better and more refined.

[@michaelbenardo5695]

@@amhicks21 In 1977, when it was introduced, it seemed fine, and I don't think anybody was yet using balance shafts. I know a friend's father bought a brand new Olds Omega in late 79 when they came out as 1980 models, and he let us drive it. We thought it was fine for a 4 cylinder, felt stronger than any foreign 4 cyl. And despite all the bad press about the first year X cars, he never had any trouble with his.

[@wingman427]

Excellent points. I can remember the shock of going from a large V8 car to a smaller much less powerful and less comfortable vehicle. Not something that I would regard as quality not to mention value.

[@shoshone3]

History is about to repeat itself, if those in power have their preferred outcome.

[@davidpowell3347]

I remember the even bigger shock of finding that a $5,700. car with a tiny 2.8 V6 in it could show its taillights from a standing start against such as the later model Ford 351,Olds 307 and Chrysler 318s -- (earlier V8s like the Olds 330,Pontiac 326/336,Ford 289 Hi Perf. ---- I suspect not)

[@cooluser23]

You forgot the Fiero. Dead reliable when driven like an economy commuter car. Destroyed instantly when driven like a mid-engined sports car.

[@WhitefolksT]

@Shawn 🏴‍☠️ Stafford 3rd gen F bodies have been mostly all destroyed by drunk men with mullets, 5 figure child support payments in arrears, and multiple felonies on their rap sheet.

[@WhitefolksT]

@Shawn 🏴‍☠️ Stafford see...you've still got your car!!! Winning 🇺🇸 👊🏻 🎂 and congrats from a 95 Z28 6spd owner.

[@greggc8088]

I loved the Iron Duke. Had one in my S-10 bought new in 88. But it was a noisey timing geared son of a gun. Also had to reseal the valve cover every 15-20K. It was still a lot more durable than any other GM 4 cylinder. Plus, as a broke young adult, I loved that the S-10 with the Iron Duke would get 30 MPG on the highway at 60 MPH.

[@michaeloliver2337]

The Iron Duke may not have been a great engine, but it has to be remembered that it came as a replacement for a terrible engine, the all aluminum Vega engine, which didn't have iron sleeves and quickly scored the cylinder walls.

[@pancudowny]

The aluminum cylinder bore were coated with a special chemical made by Dupont, and the designers made an error in calculating the engine's thermal expansion.

[@russellharper3027]

Strange that they wouldn’t actually measure and verify the thermal expansion before going to production. As I understand, they were under pressure but for an aluminum cylinder, that seems like an important thing to know.

[@user-wz1qo1cn3i]

I heard the reason the engine was called Iron Duke was to emphasize the fact that this engine was NOT made of aluminum.

[@ogr7771]

When I first saw the first video, I thought the same thing, because my very first new car was a 85 Chevy S-10 with a 4 speed and I loved it, very reliable, decent gas mileage etc. but yes it was a bullet proof, old school crude engine. Id take one again in a heart beat.

[@mikek5633]

You are right on this one. I had one in my S10 and, of course, it was reliable. When mine started knocking, they replaced my cam gear with an aftermarket metal one. Was still noisy, but I did get over 400 thou. Kilometers on it and it had an insane amount of idle time on it (volunteer firefighter). My dad had the 86 olds calais, and yes, that thing had a deafning rumble to it at idle !!! He regretted trading in his Cadillac for that thing.

[@ohioyodertoter6827]

I had a 83 omega it was noisy but extremely dependable and good on gas I loved it

[@rogermason5833]

After watching your "Iron Duke" videos, I realize how lucky I was to avoid that engine when I bought a new '82 Celebrity. We got the 2.8L V6 engine. It was pretty gutless, but had none of the Iron Duke harshness you describe.

[@keithjackson286]

It really didn't have any business being in the A-body... I drove a 6000 with an Iron Duke. It was dog slow. (or turtle)lol

[@michaelbenardo5695]

But that V6 did not have the durability of the Iron Duke.

[@ohioalphornmusicalsawman2474]

Absolutely true. My parents had an '84 Omega with the 2.5 Liter buzz bomb, which they traded for an '87 Buick Century with this motor. The Omega was slow, but the Century was dog slow. That Century should have had a 2.8 v6 for the quietness appropriate to a Buick. Both cars were junk as far as reliability as well, were burning oil before 100K miles.

[@johnh2514]

Adam - I recently found your channel and I’m so glad I did. Your insights are quite interesting…and I’m very envious of your car collection…simply amazing time capsules! I would love to see those vehicles someday. Keep up the outstanding work.

[@ELMS]

I think the determining point here is comparing the Iron Duke to any four cylinder from Toyota or Honda. Those were beautiful, smooth, user friendly engines. The Iron Duke was a good tractor engine.

[@michaelbenardo5695]

But the Japanese engines of that era were too small for an American car, even those X cars, as we Americans want strong low RPM torque, something that small engines are not capable of producing, and Japanese engines of that era were VERY NOISY, even if they were smooth-running as far as 4s go.

[@judethaddaeus9742]

@@michaelbenardo5695 Nissan and Toyota were making 2-3 liter engines in the late ‘70s and early ‘80s.

[@ELMS]

@@michaelbenardo5695 That’s a good point. They were small, probably too small to power a Citation.

[@ohcrap3263]

I have a 2016 2.7 liter 4cyl Tacoma, that engine reminds me so much of the Iron Duke I had in an S10. 85 model with a manual. The Toyota is more refined but the power feels very similar. I know the Toyota will last forever. I sold the S10 and that truck is still in use on a farm, over 300k. It finally achieved tractor status!

[@michaelbenardo5695]

@@ohcrap3263 A Toyota 4 that big? If the Iron Duke at 2.5 is 151 cubic inches, that 2.7 is even more. I never knew they made anything that size.

[@johnz8210]

TV's without a remote, the yellow pages as your only source of finding something, taking your film to the store to get developed, and the GM 2.5.

[@sking2173]

... and the full bush ...

[@ajay-xjs]

Excellent channel, I love it. Great that you take time to read the comments and are humble enough to accept them and explain further. I watch a few car channels and this is in my Top 2

[@kcindc5539]

And there it is, in all its glory! It’s a power plant, it’s a rock crusher, and it turns any vehicle into a rolling massage chair!

[@michaelbenardo5695]

But it LASTS, and it WORKS.

[@RareClassicCars]

Hilarious

[@stephendavidbailey2743]

Thanks for correct use of its [possessive] and it's [ it is ]'

[@kcindc5539]

@@stephendavidbailey2743 the added complexity of having three of them back to back to back was completely unplanned.

[@mark98070]

Looking back in time I agree with you about what nice cars and trucks GM once produced. I can see why you are fond of these cars and not so much the crap they are building today!

[@keithjackson286]

I had a friend of mine that had the balance shafted version in a five speed Grand Am... He said he loved it. His side car was an 85 Honda Accord and he said that version of the Iron Duke was ok.

[@steveoh9838]

Perfect explanation Adam, makes so much sense. Keep the interesting content flowing man.!

[@michaelmurphy6869]

Adam, I must agree with you on the overall outlook of that engine and the vehicles they were installed in. I personally never owned one, but had driven many vehicles equipped with that engine and had repaired numerous ones. To be honest, customers had both a love-hate relationship with their 2.5 equipped vehicles. The late 70's and basically the entire decade of the 80's is a time that not only GM but all the domestic manufacturers want to forget ever happened. Serious quality issues, thrown together engineering, (which probably frustrated allot of engineers, possibly due to the bean counters corner cutting. Forget the R&D, let's just see what happens approach, especially GM.) With all the new regulations coming forward (at that time) its amazing anyone of them survived. Thanks Adam for the follow up video. Keep up the good work.

[@pancudowny]

Let's not forget decisions as to power-train options, because of image-related issues... such as not making the '82 Trans-Am with a turbo V-8 (Makes it quicker than the '82 Corvette) or de-tuning the SVO Turbo 2.3L OHC I-4 for '86. (For '85: Made 205-hp vs the 5.0L V-8's 200-hp) And don't get me started on how GM killed the V-6 Chevette they threw together, but kept developing the Lotus-designed engine they really intended for it.

[@Henry_Jones]

The iron duke wasnt a bad engine. It just had bad applications. It was a great motor for the s10 and the mail truck. Terrible motor for the a bodies, n bodies and ESPECIALLY the FIERO and CAMARO

[@SomeOne_86]

yeah whoever thought putting an 87hp engine in a fucking muscle car was a good idea should have been fired on the spot.

[@keithjackson286]

@@SomeOne_86 Lol!

[@keithjackson286]

You know... It actually powered the N Bodies pretty well... It was dog slow in everything else.

[@Henry_Jones]

@@SomeOne_86 the cheif designer of the fiero didnt have a choice. He had to basically told he had to take the front end of the citation, flip it 180 degrees and modify it to make the fieros rear end. bam the rear end and engine assembly of the fiero is born. It stayed that way till 88 when it got a new irs and then it got canned.

[@SomeOne_86]

@@Henry_Jones honestly the fiero is such a missed opportunity. The car is beautiful, but the drivetrain was just so underwhelming.

[@jhancock1575]

I had a 1980 Pontiac Sunbird with the 2.5 iron duke. It had rough idle that I could never fix. Looking back, the engine was dependable but I was never happy with it. “Dieseling” was a problem also. I never bought another GM car with a 4 cylinder engine after that experience.

[@The_Future_isnt_so_Bright]

1990 Ford tempo with a 2.3L pushrod turd or 1990 Honda Accord F22A1 inline 4 with balance shafts, rear windows that roll all the way down, 5 speed auto that operates like a manual transmission internally, and glass headlights that you can change the bulb in. I could name features of this car all day, awesome vehicle and was truly over engineered in all the right ways. Except the turning radius was terrible, you couldn't remove the front rotors without total disassembly of the suspension, the transmission had no serviceable filter but it had all external shift solenoids on the case for making repairs easy, and 2 timing belts, one for waterpump and cam , the other one was REALLY tiny and drove the balance shafts. 500,000 mile cars, easily .

[@manonmars2009]

I am now of the age where I do remember the utter dismay I experienced when the new cars of 1980 and 1981 came out. The cars of the 1960s and 70s were what I call "real" cars. They had for the most part six passenger seating, a big trunk, long hood with an engine to match. You fed these cars raw meat at feeding time. The 1980s changed everything. I was so turned off that I never bought a new car in the 80s. I waited until 1993 to buy a new Volvo 240. I still drive it to this day.

[@michaelbenardo5695]

The 80s were a sad time for cars, mainly due to the EPA and CAFE.

[@greendryerlint]

And most of the 1980s cars were so underpowered. My first car was an inherited early 1970s Cadillac. It was not what you would call a fuel miser. But I used to enjoy seeing people in econoboxes furiously shifting to keep up while I just effortlessly and smoothly passed them at part throttle. I got pulled over once and the poor cop in his 1980-something cruiser (might have been one of the poor neutered Gran Furys) said he'd been trying to catch up with me for miles and I was just driving normally. (he amazingly had a good sense of humor and gave me a warning) The late 80s and 90s were such a renaissance period when electronic fuel injection arrived on the scene and once again started an 'arms race' for the most power between manufacturers.

[@judethaddaeus9742]

@@michaelbenardo5695 The oil shocks of 1973-74 and 1979-82 were a major factor in the crapification of American cars at the time.

[@michaelbenardo5695]

@@judethaddaeus9742 Yes, I lived through those, with the odd/even days, the long gas lines, them running out of gas by the time you got to the front of the line, etc. The first one, 73 - 74, didn't hurt the cars too much at first, but it spurred President Gerald Ford into pushing through the CAFE rules, that only applied to American-made vehicles, (foreign-made vehicles were covered by a much looser regulation; if they produced a Gas Guzzler, only that make and model was slapped with the Gas Guzzler tax. If Detroit did, and it dragged down their corporate Fleet Average, EVERY SINGLE CAR THEY SOLD, NO MATTER HOW ECONOMICAL IT WAS, was slapped with the tax), which did indeed lead to the eventual destruction. The 79 - 80 one, combined with Japan's heavy subsidies to their auto exports and restrictions on OUR cars being imported to THEM, finished the job.

[@calvinnickel9995]

@ Manon Mars You realize they made the Volvo 240 every year of the 80s, right? And I think you’d be disappointed in those 60s cars. Horsepower was SAE gross not net. Most of those big V8s made less than 200hp.. and 0-60 was done with a rolling start to sell magazines. Interior room was terrible because the engine and transmission and driveshaft tunnel took up space in the centre and the frame rails took up space outside. People were smaller back then, too. Good luck getting six 200+ pound Americans into one.

[@scottfelsted3203]

I had a 1987 Olds Cutlass Ciera with the Iron Duke. Great mileage, great pickup. I beat it to death. Lol I seldom drove under 85 mpg. No vibration. It was good.

[@dmiller1000]

I remember reading an article back in the 90s about how GM and Ford were so far behind Honda and Toyota in engine tech and on quality control - and it showed. Of course people ran down to these dealers. Watch old stock footage of freeway traffic from the 80s, and watch again in the early 2000s - it went from mostly Big 3 to mostly Japanese. Seems like the Big 3 were never able to make a sufficient profit on smaller cars (look at all the stumbles over the years). Now they've virtually given up. And they're now being leapfrogged by Tesla, Rivian, & Lucid on electrics. This channel has had videos about this. Can they come back or just hold their own? I guess yes/maybe - GM and Ford make and sell multinational products (assuming the world doesn't go to war), so that should be sustaining for them in some manner. But they're not special companies like they used to be.

[@wyhop6071]

I had a 1980 Oldsmobile Omega Brougham with an iron duke/manual transmission. It was nothing but problems from the day I drove it home from the dealership! One of the many problems it had was an undersized piston. It took an Oldsmobile engineer to finally figure this out. GM at its finest!

[@Ascotman]

In 1985, I was working at a Prudential Insurance Agency. One of my fellow salesman, bought a brand new Cutlass Cierra, 2 dr, with the 2.5 Iron Duke. He was very proud of it, and after showing us fellow salesmen, it would not start! Totally dead! had to have it towed back to the dealer! Another salesman bought a 1985 Fleetwood Brougham used, or Demo from a Cadillac dealer, and the HT 4100 blew up the first week he had it! To be positive, a sales manager bought a really loaded Brand New 1985 Buick Riviera, and he loved it!

[@michaelbenardo5695]

That HT 4100 was another piece of junk. It almost killed Cadillac, and would have if it was an independent automaker and not part of GM.

[@mikeharbison8762]

I was worried you were going to moderate your views on this, but your nuance and assertions about expectation ring valid for me.

[@davidchristensen6908]

I have enjoyed all your video showing off your cars. This porch chat we are having really is a home run. I agree completely about the Iron Duke. I worked with a plumbing company that used the mail trucks with this engine. We called them Armadillos. These trucks ran and ran and sounded horrible but in the mail truck version the company would buy retired mail truck for fleet use. Shop mechanic became a wizard with engines. Seems like everything only took a couple of hours to fix. It seemed like he could put a replacement engine in a couple of hours, said another engine not a rebuild engine. Love to hear your point of view.

[@MrNK1964]

Thanks for that perspective. It is particularily revealing to an European enthusiast such as me, who always thought that the Americans' distaste for 4-cylinders in the early '80s came from having been too pampered and having been used to silky-smooth V-8s for too long. Something quiet incomprehensible and unacceptable from the European perspective, as you can imagine ! :D For we, Europeans, had had to do with tiny 4-cylinders even since the 1950s.

[@michaelbenardo5695]

We Americans never really liked 4 cylinders. Not only gutless, but rough and noisy. A 6 is fine, but an 8, inline or V, is best.

[@stoneylonesome4062]

My Citroën SM has a 90° V6, there were a lot of instability problems when they were first introduced.

[@jeffreysproul9110]

GM did get better with the 4 cylinders my S-10's 2.2 was a lot smoother and did not vibrate. Also the 2.4 in my 2012 Buick Lacrosse E-assist was fairly smooth and had decent acceleration for getting on the highway or passing. GM and Ford are capable of building great vehicles when they want to and when the bean counters don't cut too bad.

[@noone-nd4ml]

People in north america loved the I6s which were strong smooth and could get good fuel enconomy. 25-35 mpg out of the smallers ones like the 170. The only problem was they wete lonb

[@michaelbenardo5695]

@@noone-nd4ml We didn't back then consider them long, as the Straight 8 was the long one.

[@Dr_Reason]

84 Fiero, 2.5 TBI, 3 speed auto.Vibration was OK. I fixed the TBI manifold porting and it would redline top gear. I spun a rod bearing.... After a patch rebuild with a new connecting rod, bearings and ARP rod bolts, it held up quite well and would bark the rear tires from a light. When we traded it the dealer took it for a spin and said it really was a quick car thanks to the V6. I did not argue with him.

[@bnjoo]

Out of the park, exactly, Adam. This perspective is excellent reason, backed by experience from childhood for my hate of GM. Your insight is exactly what happened with customers and helped to generate generations of Honda and Toyota buyers. And to that we can discuss the profile that each buyer fits as well.

[@realflagracer]

What do I think? I think you'd be great to go to a car show with! These porch chats are so refreshing. Highly enjoyable 💯

[@johna.4334]

Great video as always Adam. Keep 'em coming please.

[@brianhechinger6726]

To those who payed attention to what you said in your previous iron duke and Omega vid, you did explain your opinion and I agree with it.

[@Galfrid]

Excellent points. Context is everything!

[@stoneylonesome4062]

Dude you sound sick. Take care. I await more of the series.

[@jeffrobodine8579]

The Iron Duke was a big upgrade for the 1977 Chevy Vega/Pontiac Astre compared to the previous aluminum motor.

[@stevenlatham4397]

Excellent video. You couldn’t be more correct. These were super weird when they were in the mid engine Fiero as well. They’d about vibrate you out of the seat.

[@judethaddaeus9742]

The Fiero 2M4s with this engine had a propensity to catch fire, as well.

[@michaelbenardo5695]

When those Fieros were new, the main complaint was that they had decidedly UNsporty performance and might catch fire. Hardly anybody complained about excessive roughness. Not back then.

[@DucatiPaso750]

@@michaelbenardo5695 the news programs really had a field day with the Fiero fires. They milked it for everything they could. Yet the fires on Fieros we're on less than 1 percent of the cars.

[@michaelbenardo5695]

@@DucatiPaso750 They destroyed that car. It seemed like a pretty swell car to me, as long as you didn't try to compare it to a Ferrari or Lamborghini. Yet nothing about the Japanese cars that turn to rust a day after you bring it home. (That's one reason the Cubans don't like them - they rust too easily).

[@christianobrien4465]

100% honest and straight forward explanation of "the facts of life" regarding the GM 2.5 liter 4.cyl engine. The lest minutes of the explanation is a perfect summation of the damage the "Iron Duke" did to GM and perhaps the entire American Auto industry. That said ... I still love these cars and trucks and just like you.. it's so much easier to love them today than it would've been had I just traded in my 1973 Chevrolet Impala or C-10 on one of these vehicles. Keep up the amazing work...

[@michaelmedley8506]

I just want to say great job on your channel

[@samuelgoodman2825]

You can believe me or not,but a close friend of mine who is a lifelong mechanic had a late 80s Buick skylark with a 2.5 and after over 200k he decided to re build it and the rear main bearing only had one half of the bearing insert in the block not cap,never been apart.Never had any drivability problems.Cant explain but saw it.

[@kenzahner2682]

I agree w/your views on this engine wholeheartedly! I had a '79 Monte Carlo with a 267 V8 that I traded in on a '86 Grand Am and was disappointed on how rough this engine was. It was a fairly reliable engine (it blew a head gasket at 34k miles) but went on to 145k when I traded it in 1995.

[@keithjackson286]

My sister's Grand Am did the same thing... And it went 178k before it died

[@pokerinthefrontliqueurinth4971]

I can totally relate to the problems with the Iron Duke. My Mom had an 84 Buick skyhawk and I forgot about the idle vibration until I watched your previous video. Oh yeah and my Dad replaced the timing gear as well because of said issue.

[@bnjoo]

One of the first cd players in my friends cavalier would not play at idle. Back then the over sampling was low

[@spc_inv]

I agree with your assessment on the id 2.5L. My parents owned 2 cars in the 90’s with this engine. I still remember the buzz, diesel sound and total lack of power

[@corottolt1]

You have helped me to understand why the iron Duke was not a really great engine. I had heard some murmuring about that at GM when I worked their. I heard though that it had some racing success.

[@kipvevea5731]

In my area we had a lot of problems with headbolts breaking, I still have my extra long lefthand twist drill bit to remove the broken bolts.

[@1straightcut]

I liked your first review. I found it good and kind of funny in that it called it one of the worst, yet encouraged guys to buy one to try it. My parents had one in a Chevrolet Celebrity. My parents bought it used with 80-ish thousand miles. I thought they were going to have numerous problems with the engine, transmission and steering rack, yet they had zero! The engine was just as you said - low power, good fuel mileage, rough, etc. To me at the time, I thought completely uninspiring when you could have "foreign" car that was far more enjoyable to drive.

[@isfeldt34]

The song of my childhood. They sound pretty unique when cranking. A 1986 Pontiac 6000, and a 1977 Pontiac Astra. They just have that unique characteristic sound, you can definitely tell one ones on the road.

[@winstonsmith3685]

I remember the first time I drove a newer S10 with a 2.2L, coming from my old 2.5L Duke S10. W.O.W. I couldn’t even tell it was running at idle. I still miss the old Duke though. Paid $1100 for it used and ran the hell out of it for 5 years.

[@sking2173]

That 2.2 had balance shafts. They work !!

[@leohilke6753]

The Tech 4 name was used to heighlight 4 significant techologies used on the Iron Duke engine. These technologies are 1) Direct fire distribuless ignition using two twin plug coils 2) Throittle body fuel injection 3) Roller hydraulic vaslve lifters and 4) Fabricated stainless steel exhaust manifold. These 4 technical features were all in place by about 1982. The introduction of thes features were used on a very high volume, low cost engine approxamate;ly 5 years before they became widedspread usage in the industry. These features were developed to meet emmissions and fuel economy which were the prime drivers at that time period..

[@RareClassicCars]

Number 1 came out in 1987. Number 3 in 1985 I believe.

[@3beltwesty]

@@RareClassicCars The 1982 Iron duke in the camaro has 2) Throttle Body and 4) fabricated exhaust manifold .. It tends to "eat" them, fatigue failures due to the engines beastly shake. In California I use to replace the manifold right before each 2 year smog inspection and the O2 sensor too. Otherwise you had a loud exhaust and failed also the smog emission tests. The 1981 GM cars in California that used the same exact O2 sensor had them replaced every 12 months. GM used a fabricated stainless exhaust manifold to allow the sensor to heat up quicker to get the engine in closed loop mode quicker. Some pre 1982 non California iron dukes had a cast iron exhaust manifold and with an O2 sensor too. I got one off a junked GM Sunbird at a junkyard. 3) I believe the roller lifters came out in 1985 too.

[@brianhdueck3372]

Adam, you are absolutely right. I drove many of them though not my own. They baited a lot of sarcasm back in the day. The flood of customers flocking to the imports speaks in part to this.

[@foghornrooster7521]

Good review. Very informative.

[@troyp9485]

Honda was producing buttery smooth high revving engines that made the Iron Duke feel like a tractor engine. GM lost market share for a reason.

[@sking2173]

Basically, the “Iron Duke” was indeed a tractor engine ...

[@blautens]

I agree 100%. My roommates first new car was a 1989 S10 with the 2.5 and a 5 speed, and he was was a Porsche mechanic. He appreciated the engine for what it was, but we both knew it belonged in trucks, not cars, especially with auto trans. For that matter, I felt that way about the 2.3L in my 1981 Mustang, it was tolerable only because I could push the clutch in, but miserably rough in a car with an automatic transmission. No wonder it was my last domestic 4 cylinder.

[@tcwascawy1]

For a young man you've got a real handle on what it was like in those wild an wooly days of the late 70's through the 90's. My wifes 1970 Toyta Corona (a college grad/used car gift in 75) made almost Anything American pale in comparison. I owned a 67 Olds Delta 88 Custom and after trying Chevrolet I went to a 78Toyota Celica GT and later added a new 81 Cressida. Both lasted decades and were flawless. Almost everyone we knew with American cars then were disappointed at least. I still do love "classic" American cars 50's and 60's especially and have owned a few. But the 70-90's were an era of American Automobile disappointment and longing nostalgia. Quelle domage. Keep up the good work, really enjoy your show.

[@garymotley8196]

Adam, I understood what you were saying the first time and I think that the people got offended really weren't paying attention. My grandmother was looking at a Pontiac 6000 during that period when they were fairly new and after hearing it run, I steered her towards a 1986 Ford LTD with the smooth running 3.8. The iron Duke sounded as if it was coming apart. She was downsizing from a 1973 Pontiac Grand Prix SJ with the 455! Please don't worry about the negative comments, you know your stuff!

[@cadillacguy1890]

My father in law traded in a 1980 Citation 2.8 for a new 1986 Cutlass Ciera 2.5. Timing gear on the Ciera broke in 1994,, car had about 70,000 miles on it. FIL said “no more fours”. He was obviously disappointed with the refinement of the engine. He moved to a 1994 Buick LeSabre with the 3800 series I, and what a difference. Smoother, quieter, much more power and virtually the same fuel economy.

[@kevin122759]

What are you thoughts on Holden built GM cars, Pontiac gto, G8, Chevy SS compared to the other GM vehicles built at that time? You are so interesting to listen to. Do you have any information about the Pontiac 455 superduty?

[@DustinDriver]

You're right! Also I'd love to see a video about the Quad 4 engine. Interesting history and I guess it was pretty good although I don't have any experience with it.

[@PaulGeerE]

I had a 'Tech 4' version of the 'Iron Duke' in an 1985 Chevy Celebrity - It was 'reliable' - Starting on very cold day with the throttle body fuel injection was an adventure and the so call 'brakes' on that car made sure that you didn't tailgate! Truthfully I sort of miss the old dear...

[@kevinbarry71]

Love these videos. Maybe you could do a quick talk on morning sickness. That whole problem with GM steering racks. Another way GM sought to sell Japanese cars

[@21stcenturyfossil7]

GM expected it's customers to regain their sanity and start buying big rear wheel drive cars again. I'm pretty sure the plan was to build crummy FWD cars until the fad went away. GM figured that keeping GM customers loyal was just a matter of getting GM customers to buy cars GM wanted to make.

[@kevinbarry71]

@@21stcenturyfossil7 I guess it's sort of work. All they build nowadays are big pick up trucks and SUVs. They don't build cars anymore at least in the North American market

[@21stcenturyfossil7]

@@kevinbarry71 You are correct!

[@christopherkraft1327]

Thanks for sharing another porch chat!!! 👍👍

[@westernjeep4015]

I recall the 2.5 Pontiac being installed in the CJ Jeep platform circa 1980-83 as standard equipment. As fitted in the application, engine NVH was noticeable when compared to the 258 AMC six, which was a relatively smooth unit. The 150 AMC four, which superseded (in a manner of speaking) the 151, was a more refined, smoother engine, albeit of modest power output.

[@littlejohnny47]

Adam, I agree that GM lost a lot when customers could compare a GM 4 cylinder with a foreign competitor’s 4 cylinder. I believe GM and others continued to sell cars because many Americans being highly conservative would not consider a Japanese car at all. It is funny to see today that most of my rural neighbors have a big American pickup in the driveway next to a Toyota Camry or Highlander. Times and expectation change.

[@timothykeith1367]

In that era many rural areas did not have local dealers of Japanese cars

[@littlejohnny47]

Timothy Keith, good point! I suspect the mid-west was especially empty of dealers. New England at the time was well served as far north as Maine and east to Chicago. Odd stuff not seen elsewhere like Saab, Volvo, Subaru, etc. We serviced a Subaru 360 that was so tiny three guys could almost pick it up without a lift! Maybe the snow and ice opened eyes to alternate vehicles…?

[@drewbenefield2001]

I have owned 2 1988 Celebrity’s with the 2.5 one was my first car in 1998 250k until I was rear ended! 2 5 years ago I found another one 122k miles and runs like new! But I maintain my cars like crazy lol. Oh I have a 1990 CRX 400k miles on it. Keep up the great work!

[@Vegaswill714]

Your comments are dead spot on Adam. In 1993 I bought a Honda Accord because it was so much more refined than the American cars of the era. I sold it in2021, not kidding. That says it all. My dad was furious that I bought a Japanese car because he fought in the Pacific in WW2.

[@chriswright8464]

Pops had a 83 Pontiac 6000. GREAT CAR. Had it 15 years.

[@lcurtsinger4313]

Let me start by saying that I am in complete agreement with you, but here is the strange part that I didn't understand, I was selling Oldsmobiles at the Troy Motor Mall in the 80s, if one of those cars came in ( used) for a trade in and was equipped with a 2.8 carburetor it was a 500 deduct listed in the weekly black book that our used car manager often referred to for reference, we salesman didn't understand that,but we're told it was because of lack of fuel injection and mpg, some funny moments when someone would compliment the owner of a new Toro and tell them what a pretty Calais that is, love the content

[@jetsons101]

Two videos in one day, a double whammy, thanks. The vibrating of the Iron Duke was somewhat of a safety feature for sleepy drivers. Pull the engine to change a cam gear set, OMG. Still the best--Chevy 327. Thanks

[@votingcitizen]

You said it. I got a 88 Somerset handed down from the in-laws. Very very low miles (in-laws aged out of driving) but really cheese compared to 77 Olds or 76 Caprice or my 89 Century Limited. Nearly everything about it was a down grade - door opening/access, instrument layout, and the engine, ugh. A real POS. That Somerset was neck and neck with the 80 Fairmont for worst ride evah.

[@michaelbenardo5695]

My mother had a Mercury Zephyr, the Merc version of the Fairmont. She liked it very much. No, it didn't measure up to a Lincoln, but it didn't cost as much as a Lincoln, or even a full-sized Merc, either. And it was easy on gas, and quieter than a foreign car. 6 cyl usually is quieter than a 4.

[@votingcitizen]

@@michaelbenardo5695 The Zeph was definitely more upper crusty that the vinyl Fairmont. Those were the end of an era for FoMoCo - midsized, rear drive econoboxes. After that came the aero design era. Fairmont was the only car I ever bought new from a dealer. As required for my field sales job - american four door. I would have preferred a Caprice but that was out of my price range. The ol' Fairmont was yr most basic, reliable, quiet, family man car. Paid her off and gifted to Mom in tip top shape.

[@montymatilda]

I agree with you Adam and you didn't even touch on the lack of performance in this video.

[@codyluka8355]

I think you just nailed it right on the head, Adam. The "Iron Duke" was best suited to be teamed up with a manual transmission rather than an automatic. My Iron Duke powered 1991 S10 was equipped with a 5 speed manual and even though it was not very powerful, I could keep up with traffic on the freeway. Driving through mountain passes, however, required patience and plenty of shifting to maintain your speed. Passing, at times, could be interesting as this engine does not like to rev and it gets pretty breathless at the upper end. It might have been an "okay" engine in terms of reliability and durability but it was light-years behind all of the other 4 cylinders in the market at the time. A pushrod 4 was pretty low tech.

[@michaelbenardo5695]

But it was STURDY. And that, after experiencing the disaster of the "state of the art" Vega engine, was what we wanted. STURDY.

[@codyluka8355]

@@michaelbenardo5695 I agree, it was STURDY. To get the most out of the Iron Duke...or to make it more bearable, a manual shift was the only way to go. You had 2 more gears and they were spaced out pretty good. The automatics at that time were limited to a 3 speed which did nothing for power as the transmission sucked up what limited power it could produce. Definitely not in the same league as what the imports were putting out. A Honda with a 4 speed auto was pretty peppy at the time.

[@nick_nt7574]

I have a 1984 Pontiac Fiero with that engine with a manual transmission, and even though it was behind me, I had the sunroof rattle so much because of the engine just idling, which is why I open it when I drive the vehicle. I enjoyed the follow up video nonetheless.

[@johnlobbestael626]

My son had an '85 Somerset Regal, small V6, the phenolic button on the front of the cam (to keep it from moving forward) wore out, and that car had the WORST seats I have ever experienced!

[@remingtonwingmaster6929]

I hated them with a passion. Unrefined is giving them too much credit and I even raise an eyebrow to the reliable argument. I completely agree that it turned some people away from GM coupled with a bevy of other substandard products and QC issues. By the late 90's I gave up on my love affair with GM and turned to Honda. By the mid 2000's I gave up on GM's trucks and turned to Toyota.

[@michaelbenardo5695]

But Toyota, and the rest of the Japanese, not not make 3/4 or 1-ton pickups. Only 1/2 tons.

[@remingtonwingmaster6929]

@@michaelbenardo5695 If I needed one of those I'd go Duramax, thankfully I don't. The Toyota's have been pretty much bullet proof. The last 5.7 Vortex I had was a good truck. The 5.3 after that was not. Neither was the truck.

[@andrewinaustintx]

I agree - if you were coming from an inline 6 or a V8 - an early eighties four cylinder engine seemed agricultural. With regards to crude, but reliable - I believe the 1.8 liter four cylinder, single cam, push rod engine in a 1980 Toyota Corolla wagon that I once owned only made about 75 hp. Granted we had a 55 mph speed limit, but even the competition to the 2.5 Iron Duke could be incredibly anemic by today's standard.

[@turnne]

@Andrew in Austin You didnt experience a Honda 4 cylinder of the early 80's.....smooth as a sewing machine

[@michaelbenardo5695]

Thank you. ALL cars of that era were gutless, partly because of super-tall gearing, in the pursuit of better gas mileage in laboratory tests. My 81 Chevy 1/2 ton was that way too, a 6 cyl. manual transmission with, of all things, a 2:73 rear end. I wanted that truck as a working truck, so I immediately had a guy put in a 4:10 for me. HUGE difference in pulling power and hill climbing ability, and it actually used LESS gas in stop and go city driving.

[@pgtmr2713]

4 cyl. engines always make more noise than just about anything else. Worse as they get larger. I had a late 80's Corolla FX 1.6l ohv. It was smoother made around the same power as a Iron Duke, 0-40 it was savage, but that was gearing. It took abuse from me, Top Gear Hilux levels of abuse, with no sign of ever giving up. Toyota also had the 4AGE 1.6l which I had in an MR2, smooth, high revving, one of the best sounding 4 cyl. engines, 118hp. It had T-vis which doubled the intake runners at higher rpms. This was so it had low rpm power and high rpm. There was even a Formula Atlantic racing engine had around 250hp, and later 5 valve head engines based on the 4AGE. Truly a great engine, many would use the word legendary. The Iron Duke was an unrefined, inefficient, engine, "good" for transportation, when even at that time there were "much better" for transportation engines and cars. Both of those Toyotas were noticeably easy on the wallet for gas and maintenance and I'd even use the word fun. Straight up agricultural each and every time a bit of exhaust pipe rusted through though :-D Mercedes had one of the smoothest 4 cyl. engines back then. Porsche 944 was... okay for a noisy 4 Banger.

[@michaelbenardo5695]

@@pgtmr2713 5 valves per cylinder? That's too complex. I'll take the Iron Duke any day over those. But yes, the bigger a 4 is, the rougher and noisier it is.

[@pgtmr2713]

@@michaelbenardo5695 You'd take a 87hp engine over a 175-185 engine? Complicated doesn't matter. It will outlast the Iron Duke. Literally no downside to it.

[@sthier24]

I had a 87 Buick Century. It was silver. It had the Iron Duke. The silver paint came off the horizontal surfaces in chunks. I couldn't get GM to repaint the car. The body shop guy said..."I guess the paint didn't stick that day". The cam gear failed in the middle of no where. 200+ mile towing bill. Fixed it and got rid of it. Lost a lot of faith I had in GM after this car.

[@johnr9659]

I totally agree! I do remember driving a Chevy Citation driver education car , the whole dash and steering wheel would violently shake while stopped at a stoplight. NOT very refined I definitely would say... Does your Omega exhibit this?

[@RareClassicCars]

It did until I increased the idle speed.

[@jsd795]

Differences in opinion and going back and forth with someone about it is part of what makes talking cars fun.

[@johngoodwyn8246]

Could you give us a list of car's you own now and maybe a top ten car's that are your favorites ? Any car's that may go up in value (future collector) that are on the way up that may be a good buy right now. Thanks J.B.

[@tommcmillan3143]

Great points, thanks!

[@MM-fq3ys]

I drive a Grumman LLV every day at work, with well over 250,000 miles on all of them and held together with bubble gum and bailing wire. You’re right, they are reliable in essence of their durability; but what a punishment to drive for 6+ hours a day. The fumes, the vibration, the erratic power curve…but mostly the noise and vibration all day long. My nerves, nose, and body in general are shot by the end of the day. So yes, reliable, but definitely not a comfortable experience. Love the channel, keep up the good work. Got any Olds 98s in the barn???

[@DILLIGAF88]

Had one in a 84 Fiero and cam gear went bad, had to pull the motor to replace it. Oh the memories 😂😂

[@richgallagher725]

back in the day, people (Americans) would chalk it up to, “U.S. isn’t good at building 4cyl engines, we’re much better at V8’s”. That held true until Japan (Toyota) came out with their own V8’s, like the Lexus, then later with the LandCruiser & Tundra. Then they started dominating NASCAR races, could you have imagined !? Research the top 5 finishers of the past 10yrs of Daytona races, you’ll see the majority are Camry’s !!! Turns out what we all kind of expected all along, they’re just better at building engines, in general, than the U.S.

[@sking2173]

Do you think that NASCAR engine in those Camrys bears any resemblance to any engine that Toyota has ever built ??

[@UNCFIPP]

Im loving your videos. Is there enough interest or quirks and things(good & bad) to do a porch chat on the caddy 429/472/500??

[@RetroAnachronist]

I had one in an ‘80 Pontiac Sunbird. RWD. Automatic. Loved it. Tons of power for what it was.

[@errorsofmodernism9715]

If someone came from high revving 4 cyl OHC japanese engines, I was used to a 4 cyl Kawasacki 900 Z1 and I drove a 4 cyl Mitsubishi Mirage Turbo, when I drove my girlfriends Chevette it drove like it might be International Harvester engine. The technology was at least one or two generations behind the times.

[@calvinnickel9995]

The Chevette had an overhead cam engine.

[@garybaldwin1061]

Great explanation. I came close in 1982 to buying a new chevy citation with this engine. I had a couple small kids at the time. I guessed I dodged a bullet. I ended up getting a ford tempo a little later. However the citation looked great.

[@sking2173]

I agree with you. I thought the Citation was a fine looking car when it came out, and I loved the utility of the hatchback design; it just made sense. I guess I also dodged a bullet because I ended up getting a used 1978 Oldsmobile Cutlass with a 305 instead. That ended up being a great little car !

[@jimmy_olds]

My mom bought a new 1986 Celebrity. She then got a 1992 Saturn SL2, a car that made her Iron Duke Celebrity seem buttery smooth, then on to a 96 Lexus ES300… and never left the Lexus brand. If you’ve ever driven a Lexus you’ll know exactly how smooth and refined they are. Her Saturn was course, loud, and had a miserable ride, she bought into the quirky marketing though. With that, my brother had an 92ish SL1, which I learned how to drive a manual transmission in, and remember his being far more comfortable than hers. As course and unrefined as the pre balance shaft Iron Duke was, the Saturn engines/engine mounts/insulation were worse, at least from our experience.

[@gregblanton9386]

The iron duke 2.5 may have been a rough idling engine on the street, but in a racing application it was hard to beat with thousands of wins and many championships when mated with the pontiac cross flow head.

[@Jasona1976]

It is crude, noisy, and as unsophisticated as possible. GM should be ashamed to have ever turned out such garbage.