Ok, guys. There are some errors in this video. I mixed up the bore and stroke, amongst other things. This is what I get for trying to make a video while I was away for the weekend, without having access to my paper GM manuals. Please take it for what it is, and I'll try to do better next time. This isn't anywhere near a full-time job for me, so sometimes I have to try to put things together wherever and whenever I can.
I drive one in a 1989 Grumman LLV at work. It’s a very reliable engine if maintained. Most of my coworkers dog these engines and their trucks stay in the shop.
VMF tech here, these things are solid if they’re cared for! Considering the conditions they’re operated in, it still shocks me how well they perform overall.
@buzzwaldron6195 The Vortec 3000 was a different 4cyl based off the Chevy I6 engine. But it was very similar. The Vortec used the standard Chevy bellhousing pattern, which made it ideal for OEM's who used them in boats, pumps, and industrial equipment. It could interchange with the 4.3L and V8's. The Iron Duke used the GM Small Corporate bellhousing pattern like all other FWD engines like the 2.8L, 3.1L 3.4L and 3.8L V6's.
I got an 88 s10 with the iron Duke when I was 12. That little engine took a ridiculous amount of abuse and never skipped a beat, the head cracked eventually but it just put coolant out of the exhaust, kept the coolant topped and kept trucking lol
I dated a girl in high school that had a Camaro with the Iron Duke and a 5 speed. 1st was very low and it launched pretty well. If you drove it like a normal person, you couldn't tell the difference between the 2.5 and the 2.8 and I remember her getting almost 40 mpg on the hwy. It was only if you put it to the floor that you realized how little power it actually had. I would still have taken the 2.5 and 5 speed over the 2.8 and the 200R4.
Iron Duke one of Best Engines... no timing chain to stretch and slip, no timing belt to break... just gears drive... more power than an early Ford flathead V8...
I owned a base model Jeep CJ5 with the Iron Duke and in that application, it was a great fit. Reliable, decent gas mileage and in a Jeep CJ, no notice of any vibration and the engine would pull the CJ5 faster than I cared to try to drive it on the highway.
These engines are considered crap by many people, but they so were not. They were not powerful, and by the end of their life their fuel economy was a joke, but they were reliable. I have seen these engines with hundreds of thousands of miles on them, both well taken care of and abused. They were so under stressed that you almost could not kill them. A good friend of mine, about 24 years ago he got his driver's license, and his first vehicle was a 1982 Chevrolet S10 with an Iron Duke and a 5 speed manual. That truck was bought brand new in 1982, drove on the road from the dealership to his grandmother's house, never to see a road again till about the year 2000. It worked its entire life on a small farm. The truck was beat to high heaven, very little maintenance ever done on it and yet, when my friend and his dad put new brakes and tires on it, new fluids all around, some bushings, tie rods and shocks, the truck was on the road and happy. It got pretty decent fuel economy and it never failed to just start up and run. I will say this though, the parking brake did not work, and the engine was so worn out, you could not park the truck on any kind of slope, it would roll in gear..... I once had to hold the service brakes at the water company while my friend paid his water bill, we had to park on a steep hill.....Yet that tough little engine just kept going. They put a lot of miles on that truck before someone wiped it out while it was parked in front of their house.
Many years ago (when I was a teenager) my dad picked up an 1985 Chevy Celebrity with a 2.5. (It might be important to add that my father owned a used car dealership at the time and this came from an auto auction.) It was fairly low mileage but lacked power and would only hit 55 miles per hour with a tail wind or downhill grade. It was driven by the teenage drivers in the family for a few WEEKS before I was tasked with investigating the lack of power. I was going to hook a scanner to it to check for any DTCs, weird sensor readings, etc.. The test procedure calls for verifying the Check Engine Light is operational with the Key On Engine Off before continuing. It was not. I then realized the oil pressure light was not operational either. I pulled the instrument panel and both bulbs had been removed. (Auction car, remember?) I replaced the bulbs and started the engine to see that the oil pressure light remained lit when it was running. Further diagnosis revealed the pin had sheared on the oil pump drive shaft so the oil pump was not running. I replaced the shaft and the car ran great afterwards with normal power and no noises. I don't think there are many engines out there that could survive being driven for a couple weeks with no oil pressure whatsoever.
Bought a brand new Blue 1987 2 door Pontiac Grand Am with 2.5 , 3 speed auto. I loved it. It was Bulletproof and I towed a 16 ft Bayliner boat with no issues. Yes. It wasn't a speed demon. But that cast iron block and head was a tractor like motor. Boats used it also. It was reliable and I still see them mail trucks going strong every day. I wish they never discontinued them. These Turd engines they build today are disposable trash. Duke was the King in my eyes. I'm 62 and owned 34 vehicles. All of them had great reliable motors and trannies in them. I miss the 70's,80's,90's so much. thanks for the memories.
Well, not exactly. Grumman LLV's had them until mid 1993. For late 1993 and 1994 they had the GM 2.2L. I used to work on these for the USPS, exclusively, for a living.
I've had 2 of these in a Grand Am and a Fiero. The Grand Am always ran great. I was a teen back then, I do remember an older guy thinking something was wrong with it because of how noisy the valvetrain was at idle, but that's just how they were. The Fiero stripped the timing gear on the end of the camshaft. It's a soft material (to prevent noise), so that's a pretty common failure. It's a non-interference engine so no other damage was done. But it's still a big job to fix because you have to drop the engine and remove the cam to get a new gear on it. They sell steel gears for it, reportedly louder but it solves that failure point. My Fiero Duke also had low compression on 1 cylinder, so probably needed rings. It's one of the simplest engines you could ever hope to work on, so it would have been a great candidate for a complete overhaul and rebuild. I wanted to do that but the car had severe structural rust so I replaced it instead. The Quad-4 is a much more powerful engine, but I don't think it replaces the Duke. The Iron Duke - well named because it's all iron - is simple and durable. It's more tolerant of imperfect maintenance, and everything on it is cheap and it's easy to work on. The Quad-4 is a performer with soft aluminum heads, failure prone head gaskets, dual overhead cams and an interference design. It drives great when it's in good condition but it's easier to ruin and a lot more complicated and stress inducing to tear into. I think the Quad-4 hurt the reputation of some cars like the Cavalier. It wasn't forgiving enough for many of the young or non-enthusiast drivers who ended up owning them. I think someone who wants to be self reliant in maintaining their own car with a minimum of cost, stress and headaches would have more success with the Duke, especially if they're not an experienced mechanic yet. As such, I think the Duke is a much better *economy* engine, but the Quad-4 was a great *performance option* for small cars. The Duke's performance lagged when other engines migrated to multiport injection. The Duke never had a major update to add MPFI and to support higher levels of power. This kept it simple, but when the Chevy 2.2L did get MPFI, it replaced the Duke as an economy engine.
Back in the early 80's I had a 79 Chevy Monza 4 speed with a 2.5 Iron Duke... It was very dependable and ran pretty good. Good times and good memories.....
I had a 1980 Chevy Monza with the 151 and a 2-barrel carburetor (4-speed manual transmission). It ran like crap. Every upshift was followed by a fairly loud POP sound. It fouled out the spark plugs every couple of months or so. Its power was underwhelming, and its fuel economy peaked at maybe 26 MPG. I would imagine that most of the problem with it was the carburetor, rather than the rest of the engine, but there you have it. A few years later, I picked up a 1990 Buick Century with a TBI version of the Iron Duke, mated to a 3-speed automatic. That one left me stranded at my girlfriend's parents' house during the winter. It just refused to start. It would crank, but that's it. That car peaked at maybe 23 MPG, and although it had more horsepower than the Monza, it was still a pretty slow car. I really hated that car.
@@jamesbosworth4191 The Chevy II 153 four-banger was basically a Chevy 230 straight-six with two cylinders sectioned out of the middle. While both are 'pushrod' fours, the Pontiac 2.5 has nothing in common with the Chevy II mill. The Pontiac 2.5 was an all-new design when it was introduced in the mid 1970s. Pontiac did make a four cylinder in the 1960s that was literally the passenger side half of a 389 V8; it was called the 'Trophy Four', and it was the base engine in the Tempest prior to '64. Chevy never made fours out of their V8s, but they did make some V6s based on the small block. The 3.3, 3.8, and 4.3 90-degree V6s were based on the 267, 305, and 350 V8s, respectively. Not to be confused with the Buick V6s of similar size.
@@xaenon 1) I never said they made the Chevy II 4 out of a V8 the way Pontiac did, I said it was SORT OF 1/2 of a Chevy V8, but yes, calling it a Chevy 230 6 cyl with 2 cylinders removed is a more accurate description, I admit. 2) The Pontiac Iron Duke may have been completely new, but it was indeed based on the Chevy II engine. No, I didn't say it was the Chevy II engine, I said it was BASED on that engine. And I never implied that I think the Buick 231 V6 had anything in common with any Chevrolet engine.
@@xaenon the Iron Duke was anything but an all new design as the cylinder head , intake and exhaust manifolds would interchange with the Chevy II parts until Pontiac changed over to the cross flow head . They did change the bore and stroke to 4.00 X 3.00 ( the same as a 302 Z-28 engine ) from the earlier 3.875 X 3.25 ( which was what was the bore of a 283 with the stroke of a 327 , ironically what was also used in the 307 starting in 1968 ) .
I worked on many of these in the late 80's/early 90's. They were just like you described:Noisy, Harsh, and weak. However, they were much better than the 1.8 Pontiac Brazil and the 2.0 Chevy. I agree GM should have seen the writing on the wall and started earlier on the Quad 4, but they weren't different than Chrysler or Ford. I would happily take a 2.5 over a Ford 2.3/1.9 or most of the early Chrysler K cars. Sadly many people (and corporations), like to sit on the laurels as long as they can, and not realize the opportunity cost of competitors. The difference between a 4cylinder from North America vs Japan was significant for this time period. One thing that should be mentioned...GM developed many technologies in the 80's that are in use today. The GM Throttle Body fuel injection, Distributorless Ignition, Mass Air Flow sensors, and inexpesive ABS brakes (using traditional master cylinder vs that big honking bosch thing.
Normally I'd agree with you but owned several examples of each . The German Ford 2 liter was great once you addressed it's shortcomings forged crank and rods were standard to just a better set of valve springs and it was safe for a 7 grand redline. Ford tried fixing it's 1 weak point the 3 bearing cam and taking all the value out of the rest of the motor and the early 2.3s were crap. The motor in my 90 something Ranger was a totally different animal fuel injection and 2 plugs per cyl it was running great with over 200k when the frame dissolved beyond use.
The Quad 4 could have been a real contender to challenge and compete with the Japanese four cylinder engines that were gaining popularity because of their smoothness and reliability. GM simply refused to spend the money in engineering that it takes to ensure that you don’t turn a flawed motor loose on the buying public and then refuse to stand by it.
Our family has 2 ski boats, from the 60s...both with mercruiser iron dukes. Thousands of hours or running near full throttle. Still run reliably, with regular maintenance. Tough little engines!!!
The Mercruiser engine from the Sixties was the Chevy II version , the Iron Duke didn't come out until 1977 . There were two versions of the off shore engine offered , the first was basically the one used in the Novas modified for boating , and being a 153 cubic inches , the other one was bored and stroked for 181 inches and had a hotter camshaft and a special cylinder head . If yours has a finned cast aluminum valve cover on it , it's generally the hotter version . If memory serves it had 120 hp. compared to the 90 hp. of the stocker . The engine side cover was a casting also .
I drove a 1988 Celebrity 300k miles with one of these motors. Did exactly what is was supposed to do, delivered me to school and later to work on a daily commute of a little over 100 miles round trip every day. It did it reliably and efficiently with very few issues, namely alternator failures. The engine and transmission performed flawlessly.
I have one in a 1983 Jeep CJ 7 . I bought it new it’s on its third transmission but the engine runs absolutely perfect. It’s not fast but it’s very reliable
As the owner of 2 80s cars with iron Duke, your description and commentary is absolutely correct. They are durable but extremely crude. Tye nvh of these engines drove millions to imports
Great work explaining the history of this engine and all it's improvements. My folks had an Olds Ciera with one, and while it was noisy, it also had plenty of low-end grunt and in overdrive pulled the car just fine. Fuel economy was also admirable.
My '90 S10 is powered by an Iron Duke. It still has a distributor, however. It's still my daily driver after 34 years with 300K miles. The only time I touched the truck was to replace a water pump, alternator, EGR valve and the clutch. Sure, it's underpowered, probably why it will last forever. Best $6200 I ever spent on a new vehicle. GM don't make them like this anymore...
I owned a 1980 AMC Spirit with the Iron Duke. It was the most vibration prone engine I had ever driven. I did have the engine rebuilt and we but a reground cam in it for a bit more torque. I had highway gears in the diff and was able to get the engine to smooth out at about 60 mph and above. It did pass smog here in CA too with no problems.
Just my opinion , I think they were fairly decent engines overall. I worked in automotive field for 25 years , rairly seen any issues aside from valve cover leaks . I did a head gasket on one & didn't even need to resurface the head . The biggest issue with them , is they stopped building them
Former Pontiac/Olds tech. We used to call these engines "Iron Pukes". Made a LOT of $$$ replacing the cam gears in these. Book time was ~9 hrs, as it presumed you had to partially lift the engine. Proficient techs could replace the cam gears in less than 3 hrs. It was not unusual to have 2 of these jobs in a day.
I owned a 1990 S10 and a 1988 Celebrity with the Tech4. The Celebrity racked up almost 300,000 miles and didn’t smoke or use any oil. Both vehicles were very basic and got the job done with minimal maintenance.
I drove the snot outta my 87 s10. That thing took.me all ober the east coast. Changed the oil every 3k miles knowing that it only took 3 quarts to fill. Never had an issue
My dad had one of these in an Astro Cargo van. It got the job done, but it seemed to like mid grade better. Loaded with roofing and construction tools you weren't going to get moving to terribly fast though. It was fine when we used it as a family vehicle to start with though. Had some random full size van seats in it. LOL
Years ago, I got to work on an engine swap. We took out the V8 then fitted a 4 cylinder. The 4 was a Diesel ( 8 was a gas sniffer ) the vehicle was an International truck.
Many would be shocked to learn that these engines were used in the mid to late 90s Dodge Dakota " sport" base midsize pickups. Dodge must've gained tooling rights from GM for pennies on the dollar. Extremely underpowered was an understatement.
Hi everyone, I think these videos are great. Is there any possibility of a video on the LT1 from the 90's. That video on the Tuned Port Inj. was really cool. Thanks
The iron duke was unrefined and rough. But in my opinion a great tough little 4 banger. I had one in my 91 S10 and could at least bark the tires hitting 2nd gear.
The old Iron Duke was a tough durable and reliable engine, the problem was it didnt originally have balance shaft so NVH was horrific. Also it was underpowered, so with bad NVH and not that powerful it garnered a bad reputation compared to its smoother running quieter Japanese counterparts.
They should have used a timing chain instead of gears because the gears rattled loudly. After one had a few miles on it, you can hear it coming around the block. Also, it was hard to keep the valve cover from leaking. But it was fairly durable. In fact it was much more durable than the quad 4 that replaced it. The quad 4 had more power, but the reliability serviceability were trash compare to the iron Duke
@@AnthonyEvelyn the fact that they replaced the iron Duke with the smaller, less powerful 2.2 l as the base engine in the S10 rather than with the more powerful quad 4 pretty much tells you what you need to know about the reliability of the quad 4. For all of the iron Duke's faults, at least it was reliable I'm fairly easy to work on.
I thought the Iron Duke was replaced by the LN2 2.2L/Vortec 2200 across the board in all S-truck chassis based vehicles? Also: Given how GM had already introduce their MPI system on the LN2 in '92, which relied upon crank inputs from the same 6+1 crankshaft trigger wheel system to also drive it's DIS--which, itself, was also shared with the Iron Duke--I'm surprised GM didn't adopt the same fuel system to the Iron Duke, which would've extended it's life considerably, and allowed for intake manifold tuning that would've substantially improved low-end torque... thereby making it more of a suitable engine for light-truck applications. I guess GM couldn't justify the development cost, and wanted to go with a newer engine design to match the image of it's "all-new" 2nd-gen S-trucks. Shame... because I would've loved seeing what the output would be with that on one fitted with the longer stroke crank used in the 3L Marine/Industrial versions of it...!😕
You are 100% correct on all fronts! Another classic case of General Motors rushing something way too soon into production, before perfecting it! Plus not learning from their mistakes and keeping it way too long into production. I think General Motors key problem was sleeping on turbo charging! They had been using turbos off and on since the late 50's early 60's with the Oldsmobile and Chevrolet. Then perfected it in the early 80's with Buick! Pontiac and Buick should have collaborate on turbo 4 and 6 cylinder engines. But by that time GM had went to the corporate engine policy. 😢
Show me proof that Chevrolet and Oldsmobile were using turbos in the late fifties and early Sixties . Both divisions ran Tri power setups back then , and Chevy had fuel injection as did Pontiac for a time .
@@bobbrinkerhoff3592 Oldsmobile jetfire turbo rocket V8 early 60's and Chevrolet Corvairs of the early 1960s. Reading is fundamental! Get R.I.F it pays!🤣
@@crw3673 and just when was the last time that you have seen either one of those examples , cause I have never seen one , and I'm old enough to remember those days . Can we say very limited production numbers .
@@bobbrinkerhoff3592 stop being a hater! You ask for proof and I gave you the cliff notes.😂 You should have looked it up and said wow, you learn something knew every day.
The history of the Oldsmobile was that the engine needed distilled water to run, but most people never refilled the reservoir and hurt the engine. The history of the Chevrolet Corvairs were that they were rear mounted air cooled engines. That Don Yenko made a race car with. The Corvairs got discounted when a guy wrote a book. "Dangerous at any speed". That book destroyed the corvair reputation and GM discontinued the whole series. Their was a coupe, sedan and van, maybe a station wagon also. That competed directly against the Volkswagen, with their rear engine, air cooled vehicles. By the way I just turned 51! So this was before my time.😂
0.40 - whilst looking to see what other GM divisions were doing at the time, lucky they either didn't look hard or just ran away when they saw the ridiculous Starfire 4 that Holden was just about to gift to the nation :D
The problem this engine had as fwd at first was the power steering pump mounting brackets that would bent out of line causing belt wear. The engine would find use again in the fwd A-body in 1982 Cierra, 6000, Century.
If a person added an electric water pump to the 2.5 they would add a good deal of hp by cutting the cooling fan. There is not much way on the 1992 2.5L to actually do anything to the block or head that will accommodate more horsepower on those versions. The cams aren't out there for those 2.5L TBI versions, and hard to get the correct lift cam. Most likely get 120Hp out of it tops all worked over with porting and everything for the price of a custom ground cam to boot. I bought a 92 in 99 that was overheated and thought I could stock part overhaul the engine and everything would be fine. Ran into issues with the machine shop and more headaches than an engine could be worth. Not money wise. Parts wise. Almost sure the machine shop rebuilt the good head with the overheated rocker arms and valve springs off of the bad head we had checked. 3 cylinders would read 85lb at times, and then retest 130lb. Only 1 cylinder was consistent at 150 lb. First thought was the new lifters, not that. Let it break in, but she was stubborn and rough to idle cold and had a feedback in the steering column that caused the dash gages to increase their gauge as the system current got higher. Rev the engine and the gas hand would go from a quarter to 3/8 tank and back to 1/4, just flipping the throttle. The problem with the engine was the "stock" rocker arms had bent themselves some and the springs had gotten cooked by the old man that owned it, when I bought it for $500. Good deal until getting into all that issue with the rockers getting mixed up. I had a 1970 350/300 way back then to insert right into the s10 when I bought it. Shame I didn't. I could have re-ringed and threw an entire set of bearings in the 350 for next to nothing.
@Jazc-mp889 Some very small ones maybe, but we didn't make any cars that were small enough and light enough for those engines. This engine was fine for what it was intended to be.
@Jazc-mp889 Most of the people complaining about roughness and vibration are talking about the course "buzzing" feeling at speed more than a rough idle. Many cars of the 70s and early 80s had a less than silky smooth idle due to having to meet EPA mandates - lean idle mixtures and retarded ignition timing were required, and a lean idle mixture often means a rough idle, as does retarded timing, even in a V8. Fuel injection when a long way toward fixing that, computerized ignition systems did the rest, but both came with a downside - you often can't repair such cars at home in your driveway, you have to bring them to a shop if something is amis.
I started out as a mechanic in 1991 and worked on many of these. they have a distinctive cranking rythem that you can hear across the shop. When distributorless ignition came in it was a real pain changing the crank sensor because it was mounted on back of the engine behind the coil pack. I replaced many timing gears as well. those were the days for a mechanic, the cars were really junk.
Owned two or three A-bodies with this engine. It was resonably responsive in those, and very dependable. Didn't EVER belong in a Camaro/Firebird, that is when the HATE started +
@@Santor- GM Throttle Body injection was the best in the 80's. Very reliable, easy to diagnose, and parts were cheap. It was more advanced than the Bosch mechanical injection, but was great for things like cavaliers, grand ams, etc. It was also great when the chevy v8's got throttle body injection. They ran great, lasted forever, and had very little problems. It was the perfect answer to what was needed for getting started in fuel injection. The Ford system with it's crazy testing system, and chrysler map sensors, were over engineered junk. Others made more power (significantly for the Ford 5.0/302), but they were very problematic for a small amount of power gain.
Their ignition performance is nothing to sneeze at either , some having a plug gap of .080 on the high side and plenty around .060 as typical. These things always sounded like they were on the verge of rod knock but i do find some of their engineering decent ,like the ignitions.
Yup. Had a '93 Suburban 5.7 with TBI. Smoothest running, most reliable vehicle I've ever owned. Kind of missed the secondaries on the Quadrajet opening up at full throttle, but tbi was more reliable.
I had an GMC S-15 with a manual transmission in one and it was adequate. NVH was awful. MPG was good. At idle it sounded like there was something loose in side the engine like it rattled but that was its character.
You can’t call an engine “bad” just because it’s a “dog”. It might be the wrong engine for the application but that doesn’t make it a bad engine. The Iron Duke was certainly the wrong engine for most of the applications it was used in but it was a good engine.
Wow every comment is positive about the iron duke 2.5. Bought a new 87 celebrity with the duke. Was junk from day one. Couldn't move the car well. It would stall out in reverse w/ac on and dealer could never fix it. Always had it in for repairs whether it was a power steering belt issue, not starting when below 50°F, trans not shifting, tps problems, the list goes on. Hated that 2.5
It's possible the problems that the quad-4 had was why it was kept in production so long. The time of people who bought Cutlass Cieras and Centuries we're demographically more interested in simplicity and reliability. If they were interested in new technology they would have bought a w body car instead so I can understand why they would stick with the iron Duke. I don't see as much a problem with the iron Duke in the N cars as much as I do with a Camaro/ firebird. Considering how it was configured, it encouraged them to buy the V6 for not that much more money and clearly that's what GM wanted them to buy anyhow.
I speak from experience about the demographics on this as my father had one and many family friends had theirs who were very careful with money. They were the type of people that a car is a appliance and nothing more. If you bring up the idea for valves per cylinder You would hear a rant about unnecessary complications, extra maintenance, extra cost, and so forth. Please note, This is not meant as a mockery just as a window into the way they see things. They have some valid points that should be considered more often especially when trying to understand the general public.
Didn't Cosworth make a DOHC head for these,? I believe they did.....I once drove an ASTRO van that came with the Iron Duke and a T4 manual transmission, way cool and surprisingly peppy.
Their biggest mistake was the same mistake all 4 american manufacturers made when they transitioned to 4 cylinders: they didnt account for power drawn by accessories. For example, they often used the same belt driven fans as the v8s. That fan might cost 10 hp to run at 5000 rpm. On a 200 hp v8, that 10 hp parasitic loss isnt noticable. On a 100 hp i4, that 10 hp IS noticable.
Compared to the POS engine that was in the Chevy Vega, the Iron Duke was a great engine. Only Chevy had the Aluminum block engine in their compact, all others got the Iron Duke. Good enough reason to NOT by a Chevy if you wanted a basic small car.
EXACTLY, the IRON PUKES should have been replaced by Quad 4s. If the Fiero had been extended iunto the 89/90years, the Iron pukes where going to be replaced as the base engine with the H/O Quad 4.
I think overall they were pretty good engines. However, they did sound like a diesel engine and that’s due to the fact that they had piston slap or even sometimes in some cases wrist pin knock you could have the engine rebuilt and the noise would go away but only for a short time the post office trucks still have them today in 2024 that tells you they must be pretty good for the most part
Its only problem was that it was too good. NEVER let me down in any vehicle one was in. My only problem was recognizing when GM did somethin right, if I would have I'd still be driven the '88 S-10 and Ida kept the one outa the other '88 for a colorado.
Stout little engines. We found them to be durable and able to handle abuse offroad. Not powerful, but they would start in the cold and operate under harsh conditions. Comparisons to agricultural engines is very fair and in this case, even flattering.
The iron duke was a good motor however it was underpowered in most cars GM put it in at 98 HP and 134 torque it couldn't move much....but they worked good in boats and had a few of them
@2:50, I don't think these were ever in the "J" cars, such as the Cavalier. Really unrefined engine, but there were zillions of them made, and millions still on the road.
THIS IS ABSOLUTELY TRUE. THE VEGA ENGINE WAS THE AWFUL ENGINE THAT WORE OUT AT 50,000 MILES. THE IRON DUKE WAS THE REPLACEMENT FOR THAT ENGINE, AND IT WAS MUCH MUCH BETTER AND WAY MORE RELIABLE.
They just shit oil everywhere. How many Burned up Fieros did we see? Too many. Gutless, but if you kept oil in them they would take you all the way to the fire. Hated working on them because we had to pressure wash them before doing any work. The balls GM had to put that boat anchor in a Camaro. I test drove an Iron Duke powered Camaro in the mid 1980s for a brake concern and thought the cat converters were clogged because it was so slow. EDIT: Smokey Yunik did some development work on a turbocharged Iron Duke.
I didnt hate it. One could get it in a canaro too. You could race vanagons, and win. Only shane is one couldn't get it in Cadillacs, Caprice and K5 Blazer's. Not even the Corvette. Solution was to buy a used chevette and transplant the 4 from that.
Compared to the reliability and drivability that Toyota and Honda were offering in their 4 cylinder engines of the same time period the Iron Duke was garbage. I think the engine was more like Iron Dookie and I worked on plenty of them as a mechanic.
Click bait. You dont know what you are talking about. One of the most durable and reliable gm engines. I had two citations w 2.5 litre iron dukes. Never touched them. Owned these cars for 8 years.
A rude, crude, oil leaking, timing gear knocking, head bolt breaking, exhaust manifold cracking NVH disaster. TBI, DI and the balance shaft were lipstick on a pig. The later LLVs used the 2.2 from the J boxen.
I've had multiple cars and trucks with his motor!! All had over 300xxx on them one had 417xxx on it so say whatbu want to I've love this motor with a 5 spd behind it
This motor was not fit to be installed in anything. Maybe it worked in the Chevy Citation until a more modern replacement that was competitive with the imports unfortunately not. It was put in just about everything and GM paid the price.
This entire thing is totally bogus, I have never known anybody that didn't love this engine, our family had plenty of them, on the noisy side, that being said one of the best 4 cylinders ever made, they would tow a load just fine, run for hundreds of thousands of miles, decades, the very best thing, the now known superior pushrod design.
I wish it was still being made, along with the 3.8 general motors can't build a 4 or 6 cylinder to save itself. Everything modern is trash. The v8's are good 👍
Ok, guys. There are some errors in this video. I mixed up the bore and stroke, amongst other things. This is what I get for trying to make a video while I was away for the weekend, without having access to my paper GM manuals. Please take it for what it is, and I'll try to do better next time. This isn't anywhere near a full-time job for me, so sometimes I have to try to put things together wherever and whenever I can.
I drive this engine every day. For 25 years I have been piloting a Grumman LLV as a letter carrier. Slow but it's still running after 30+ years!
I love hearing them coming from a distance, they sound like my Fiero
Exactly what I was going to say.
Some of them have the 2.2l. pretty sure mine has the 2.5 though.
I drive one in a 1989 Grumman LLV at work. It’s a very reliable engine if maintained. Most of my coworkers dog these engines and their trucks stay in the shop.
VMF tech here, these things are solid if they’re cared for! Considering the conditions they’re operated in, it still shocks me how well they perform overall.
The Super Duty Iron Duke in the Fiero Pace Car was upgraded to 2.7 liters and had over 200 horsepower
Iron Duke 4 up to 3.0L in marine use...
@@buzzwaldron6195 Runs damn good too, carburetor and exhaust are both on the same side of head. Also used in forklifts.
@@thisisyourcaptainspeaking2259 - I still have two Iron Dukes, '85 Pontiac Fiero and rare '77 Pontiac Astre FORMULA Safari (kammback) Station Wagon...
@buzzwaldron6195 The Vortec 3000 was a different 4cyl based off the Chevy I6 engine. But it was very similar. The Vortec used the standard Chevy bellhousing pattern, which made it ideal for OEM's who used them in boats, pumps, and industrial equipment. It could interchange with the 4.3L and V8's. The Iron Duke used the GM Small Corporate bellhousing pattern like all other FWD engines like the 2.8L, 3.1L 3.4L and 3.8L V6's.
I got an 88 s10 with the iron Duke when I was 12. That little engine took a ridiculous amount of abuse and never skipped a beat, the head cracked eventually but it just put coolant out of the exhaust, kept the coolant topped and kept trucking lol
Never had a problem with this engine in anything I've owned it in
I dated a girl in high school that had a Camaro with the Iron Duke and a 5 speed. 1st was very low and it launched pretty well. If you drove it like a normal person, you couldn't tell the difference between the 2.5 and the 2.8 and I remember her getting almost 40 mpg on the hwy. It was only if you put it to the floor that you realized how little power it actually had. I would still have taken the 2.5 and 5 speed over the 2.8 and the 200R4.
Loved my iron Duke in my 83 6000. Got up to 39 mph per imperial gallon. Not a rocket but always willing to pull!
I like all the old car pics.
The iron duke is very solid and can withstand staggering amounts of neglect and abuse.
Thank you. And you're absolutely right. They were very tough.
Iron Duke one of Best Engines... no timing chain to stretch and slip, no timing belt to break... just gears drive... more power than an early Ford flathead V8...
Our experience in an early Citation is that it was a terrific boat anchor.
@@buzzwaldron6195 More power than an old flathead V8 is not a plus.
@@buzzwaldron6195 The plastic gear would go out though...
I owned a base model Jeep CJ5 with the Iron Duke and in that application, it was a great fit. Reliable, decent gas mileage and in a Jeep CJ, no notice of any vibration and the engine would pull the CJ5 faster than I cared to try to drive it on the highway.
* four inch bore, 3 inch stroke.
I have seen these in various forklift brands until very recently so they've still been making them somewhere.
These engines are considered crap by many people, but they so were not. They were not powerful, and by the end of their life their fuel economy was a joke, but they were reliable. I have seen these engines with hundreds of thousands of miles on them, both well taken care of and abused. They were so under stressed that you almost could not kill them. A good friend of mine, about 24 years ago he got his driver's license, and his first vehicle was a 1982 Chevrolet S10 with an Iron Duke and a 5 speed manual. That truck was bought brand new in 1982, drove on the road from the dealership to his grandmother's house, never to see a road again till about the year 2000. It worked its entire life on a small farm. The truck was beat to high heaven, very little maintenance ever done on it and yet, when my friend and his dad put new brakes and tires on it, new fluids all around, some bushings, tie rods and shocks, the truck was on the road and happy. It got pretty decent fuel economy and it never failed to just start up and run. I will say this though, the parking brake did not work, and the engine was so worn out, you could not park the truck on any kind of slope, it would roll in gear..... I once had to hold the service brakes at the water company while my friend paid his water bill, we had to park on a steep hill.....Yet that tough little engine just kept going. They put a lot of miles on that truck before someone wiped it out while it was parked in front of their house.
Many years ago (when I was a teenager) my dad picked up an 1985 Chevy Celebrity with a 2.5. (It might be important to add that my father owned a used car dealership at the time and this came from an auto auction.) It was fairly low mileage but lacked power and would only hit 55 miles per hour with a tail wind or downhill grade. It was driven by the teenage drivers in the family for a few WEEKS before I was tasked with investigating the lack of power.
I was going to hook a scanner to it to check for any DTCs, weird sensor readings, etc.. The test procedure calls for verifying the Check Engine Light is operational with the Key On Engine Off before continuing. It was not. I then realized the oil pressure light was not operational either. I pulled the instrument panel and both bulbs had been removed. (Auction car, remember?) I replaced the bulbs and started the engine to see that the oil pressure light remained lit when it was running. Further diagnosis revealed the pin had sheared on the oil pump drive shaft so the oil pump was not running. I replaced the shaft and the car ran great afterwards with normal power and no noises. I don't think there are many engines out there that could survive being driven for a couple weeks with no oil pressure whatsoever.
8:04
Bought a brand new Blue 1987 2 door Pontiac Grand Am with 2.5 , 3 speed auto. I loved it. It was Bulletproof and I towed a 16 ft Bayliner boat with no issues. Yes. It wasn't a speed demon. But that cast iron block and head was a tractor like motor. Boats used it also. It was reliable and I still see them mail trucks going strong every day. I wish they never discontinued them. These Turd engines they build today are disposable trash. Duke was the King in my eyes. I'm 62 and owned 34 vehicles. All of them had great reliable motors and trannies in them. I miss the 70's,80's,90's so much. thanks for the memories.
Well, not exactly. Grumman LLV's had them until mid 1993. For late 1993 and 1994 they had the GM 2.2L. I used to work on these for the USPS, exclusively, for a living.
Great comment. I was going to say this. Which engine was better overall? I assume the 2.2 is smoother, had more power, but a little less torque.
I've had 2 of these in a Grand Am and a Fiero. The Grand Am always ran great. I was a teen back then, I do remember an older guy thinking something was wrong with it because of how noisy the valvetrain was at idle, but that's just how they were.
The Fiero stripped the timing gear on the end of the camshaft. It's a soft material (to prevent noise), so that's a pretty common failure. It's a non-interference engine so no other damage was done. But it's still a big job to fix because you have to drop the engine and remove the cam to get a new gear on it. They sell steel gears for it, reportedly louder but it solves that failure point.
My Fiero Duke also had low compression on 1 cylinder, so probably needed rings. It's one of the simplest engines you could ever hope to work on, so it would have been a great candidate for a complete overhaul and rebuild. I wanted to do that but the car had severe structural rust so I replaced it instead.
The Quad-4 is a much more powerful engine, but I don't think it replaces the Duke. The Iron Duke - well named because it's all iron - is simple and durable. It's more tolerant of imperfect maintenance, and everything on it is cheap and it's easy to work on. The Quad-4 is a performer with soft aluminum heads, failure prone head gaskets, dual overhead cams and an interference design. It drives great when it's in good condition but it's easier to ruin and a lot more complicated and stress inducing to tear into.
I think the Quad-4 hurt the reputation of some cars like the Cavalier. It wasn't forgiving enough for many of the young or non-enthusiast drivers who ended up owning them.
I think someone who wants to be self reliant in maintaining their own car with a minimum of cost, stress and headaches would have more success with the Duke, especially if they're not an experienced mechanic yet.
As such, I think the Duke is a much better *economy* engine, but the Quad-4 was a great *performance option* for small cars.
The Duke's performance lagged when other engines migrated to multiport injection. The Duke never had a major update to add MPFI and to support higher levels of power. This kept it simple, but when the Chevy 2.2L did get MPFI, it replaced the Duke as an economy engine.
Back in the early 80's I had a 79 Chevy Monza 4 speed with a 2.5 Iron Duke... It was very dependable and ran pretty good. Good times and good memories.....
I had a 1980 Chevy Monza with the 151 and a 2-barrel carburetor (4-speed manual transmission). It ran like crap. Every upshift was followed by a fairly loud POP sound. It fouled out the spark plugs every couple of months or so. Its power was underwhelming, and its fuel economy peaked at maybe 26 MPG. I would imagine that most of the problem with it was the carburetor, rather than the rest of the engine, but there you have it.
A few years later, I picked up a 1990 Buick Century with a TBI version of the Iron Duke, mated to a 3-speed automatic. That one left me stranded at my girlfriend's parents' house during the winter. It just refused to start. It would crank, but that's it. That car peaked at maybe 23 MPG, and although it had more horsepower than the Monza, it was still a pretty slow car. I really hated that car.
Conceived in the sixties by Buick! I never ever knew anybody who disliked this motor!
Not conceived by Buick, this was based on the old Chevy II engine, and THAT engine was based on half of a 283.
@@jamesbosworth4191 The Chevy II 153 four-banger was basically a Chevy 230 straight-six with two cylinders sectioned out of the middle.
While both are 'pushrod' fours, the Pontiac 2.5 has nothing in common with the Chevy II mill. The Pontiac 2.5 was an all-new design when it was introduced in the mid 1970s.
Pontiac did make a four cylinder in the 1960s that was literally the passenger side half of a 389 V8; it was called the 'Trophy Four', and it was the base engine in the Tempest prior to '64.
Chevy never made fours out of their V8s, but they did make some V6s based on the small block. The 3.3, 3.8, and 4.3 90-degree V6s were based on the 267, 305, and 350 V8s, respectively.
Not to be confused with the Buick V6s of similar size.
@@xaenon 1) I never said they made the Chevy II 4 out of a V8 the way Pontiac did, I said it was SORT OF 1/2 of a Chevy V8, but yes, calling it a Chevy 230 6 cyl with 2 cylinders removed is a more accurate description, I admit. 2) The Pontiac Iron Duke may have been completely new, but it was indeed based on the Chevy II engine. No, I didn't say it was the Chevy II engine, I said it was BASED on that engine. And I never implied that I think the Buick 231 V6 had anything in common with any Chevrolet engine.
@@xaenon the Iron Duke was anything but an all new design as the cylinder head , intake and exhaust manifolds would interchange with the Chevy II parts until Pontiac changed over to the cross flow head . They did change the bore and stroke to 4.00 X 3.00 ( the same as a 302 Z-28 engine ) from the earlier 3.875 X 3.25 ( which was what was the bore of a 283 with the stroke of a 327 , ironically what was also used in the 307 starting in 1968 ) .
I like it because you know when the mail man is in the neighborhood.
I worked on many of these in the late 80's/early 90's. They were just like you described:Noisy, Harsh, and weak. However, they were much better than the 1.8 Pontiac Brazil and the 2.0 Chevy.
I agree GM should have seen the writing on the wall and started earlier on the Quad 4, but they weren't different than Chrysler or Ford. I would happily take a 2.5 over a Ford 2.3/1.9 or most of the early Chrysler K cars.
Sadly many people (and corporations), like to sit on the laurels as long as they can, and not realize the opportunity cost of competitors. The difference between a 4cylinder from North America vs Japan was significant for this time period.
One thing that should be mentioned...GM developed many technologies in the 80's that are in use today. The GM Throttle Body fuel injection, Distributorless Ignition, Mass Air Flow sensors, and inexpesive ABS brakes (using traditional master cylinder vs that big honking bosch thing.
Yep i already made my comment about how they always sounded like they were developing a rod knock even when brand new,so i wont make another 😂
Normally I'd agree with you but owned several examples of each . The German Ford 2 liter was great once you addressed it's shortcomings forged crank and rods were standard to just a better set of valve springs and it was safe for a 7 grand redline. Ford tried fixing it's 1 weak point the 3 bearing cam and taking all the value out of the rest of the motor and the early 2.3s were crap. The motor in my 90 something Ranger was a totally different animal fuel injection and 2 plugs per cyl it was running great with over 200k when the frame dissolved beyond use.
The Quad 4 could have been a real contender to challenge and compete with the Japanese four cylinder engines that were gaining popularity because of their smoothness and reliability. GM simply refused to spend the money in engineering that it takes to ensure that you don’t turn a flawed motor loose on the buying public and then refuse to stand by it.
Please do a video about the Quad 4. I remember thinking they had a lot of umph for a 4 banger back then.
Already done:
ruclips.net/video/lXlfP_1y2Kc/видео.html
But a horrible head
Our family has 2 ski boats, from the 60s...both with mercruiser iron dukes.
Thousands of hours or running near full throttle.
Still run reliably, with regular maintenance.
Tough little engines!!!
The Mercruiser engine from the Sixties was the Chevy II version , the Iron Duke didn't come out until 1977 . There were two versions of the off shore engine offered , the first was basically the one used in the Novas modified for boating , and being a 153 cubic inches , the other one was bored and stroked for 181 inches and had a hotter camshaft and a special cylinder head . If yours has a finned cast aluminum valve cover on it , it's generally the hotter version . If memory serves it had 120 hp. compared to the 90 hp. of the stocker . The engine side cover was a casting also .
I drove a 1988 Celebrity 300k miles with one of these motors. Did exactly what is was supposed to do, delivered me to school and later to work on a daily commute of a little over 100 miles round trip every day. It did it reliably and efficiently with very few issues, namely alternator failures. The engine and transmission performed flawlessly.
I had an 88 Celebrity 2.5 too. I ran like a clock, and was excellent on gas. TBFI was great.
I have one in a 1983 Jeep CJ 7 . I bought it new it’s on its third transmission but the engine runs absolutely perfect. It’s not fast but it’s very reliable
As the owner of 2 80s cars with iron Duke, your description and commentary is absolutely correct. They are durable but extremely crude. Tye nvh of these engines drove millions to imports
Great work explaining the history of this engine and all it's improvements. My folks had an Olds Ciera with one, and while it was noisy, it also had plenty of low-end grunt and in overdrive pulled the car just fine. Fuel economy was also admirable.
My '90 S10 is powered by an Iron Duke. It still has a distributor, however. It's still my daily driver after 34 years with 300K miles. The only time I touched the truck was to replace a water pump, alternator, EGR valve and the clutch. Sure, it's underpowered, probably why it will last forever. Best $6200 I ever spent on a new vehicle. GM don't make them like this anymore...
I owned a 1980 AMC Spirit with the Iron Duke. It was the most vibration prone engine I had ever driven. I did have the engine rebuilt and we but a reground cam in it for a bit more torque. I had highway gears in the diff and was able to get the engine to smooth out at about 60 mph and above. It did pass smog here in CA too with no problems.
I still have it in my '81 Eagle. There's a video of it on my channel.
Just my opinion , I think they were fairly decent engines overall. I worked in automotive field for 25 years , rairly seen any issues aside from valve cover leaks . I did a head gasket on one & didn't even need to resurface the head . The biggest issue with them , is they stopped building them
Former Pontiac/Olds tech. We used to call these engines "Iron Pukes". Made a LOT of $$$ replacing the cam gears in these. Book time was ~9 hrs, as it presumed you had to partially lift the engine. Proficient techs could replace the cam gears in less than 3 hrs. It was not unusual to have 2 of these jobs in a day.
I owned a 1990 S10 and a 1988 Celebrity with the Tech4. The Celebrity racked up almost 300,000 miles and didn’t smoke or use any oil. Both vehicles were very basic and got the job done with minimal maintenance.
I drove the snot outta my 87 s10. That thing took.me all ober the east coast. Changed the oil every 3k miles knowing that it only took 3 quarts to fill. Never had an issue
Had a Pontiac sunbird with one of those engines, never a problem.
My dad had one of these in an Astro Cargo van. It got the job done, but it seemed to like mid grade better. Loaded with roofing and construction tools you weren't going to get moving to terribly fast though. It was fine when we used it as a family vehicle to start with though. Had some random full size van seats in it. LOL
Years ago, I got to work on an engine swap. We took out the V8 then fitted a 4 cylinder.
The 4 was a Diesel ( 8 was a gas sniffer ) the vehicle was an International truck.
Many would be shocked to learn that these engines were used in the mid to late 90s Dodge Dakota " sport" base midsize pickups. Dodge must've gained tooling rights from GM for pennies on the dollar. Extremely underpowered was an understatement.
A friend of mine had this engine in his Camo EL pickup and it was good
Hi everyone, I think these videos are great. Is there any possibility of a video on the LT1 from the 90's. That video on the Tuned Port Inj. was really cool. Thanks
The iron duke was unrefined and rough. But in my opinion a great tough little 4 banger. I had one in my 91 S10 and could at least bark the tires hitting 2nd gear.
1980 Monza- bulletproof and reliable, many good memories..
The old Iron Duke was a tough durable and reliable engine, the problem was it didnt originally have balance shaft so NVH was horrific. Also it was underpowered, so with bad NVH and not that powerful it garnered a bad reputation compared to its smoother running quieter Japanese counterparts.
Rough as a cob!
They should have used a timing chain instead of gears because the gears rattled loudly. After one had a few miles on it, you can hear it coming around the block. Also, it was hard to keep the valve cover from leaking. But it was fairly durable. In fact it was much more durable than the quad 4 that replaced it. The quad 4 had more power, but the reliability serviceability were trash compare to the iron Duke
But it had way more torque than those pint-sized Japanese 4s.
@@dmandman9 Yep! In many ways the Quad 4 wasn't up to par either.
@@AnthonyEvelyn the fact that they replaced the iron Duke with the smaller, less powerful 2.2 l as the base engine in the S10 rather than with the more powerful quad 4 pretty much tells you what you need to know about the reliability of the quad 4. For all of the iron Duke's faults, at least it was reliable I'm fairly easy to work on.
I thought the Iron Duke was replaced by the LN2 2.2L/Vortec 2200 across the board in all S-truck chassis based vehicles?
Also: Given how GM had already introduce their MPI system on the LN2 in '92, which relied upon crank inputs from the same 6+1 crankshaft trigger wheel system to also drive it's DIS--which, itself, was also shared with the Iron Duke--I'm surprised GM didn't adopt the same fuel system to the Iron Duke, which would've extended it's life considerably, and allowed for intake manifold tuning that would've substantially improved low-end torque... thereby making it more of a suitable engine for light-truck applications.
I guess GM couldn't justify the development cost, and wanted to go with a newer engine design to match the image of it's "all-new" 2nd-gen S-trucks. Shame... because I would've loved seeing what the output would be with that on one fitted with the longer stroke crank used in the 3L Marine/Industrial versions of it...!😕
You are 100% correct on all fronts!
Another classic case of General Motors rushing something way too soon into production, before perfecting it!
Plus not learning from their mistakes and keeping it way too long into production.
I think General Motors key problem was sleeping on turbo charging!
They had been using turbos off and on since the late 50's early 60's with the Oldsmobile and Chevrolet. Then perfected it in the early 80's with Buick!
Pontiac and Buick should have collaborate on turbo 4 and 6 cylinder engines. But by that time GM had went to the corporate engine policy. 😢
Show me proof that Chevrolet and Oldsmobile were using turbos in the late fifties and early Sixties . Both divisions ran Tri power setups back then , and Chevy had fuel injection as did Pontiac for a time .
@@bobbrinkerhoff3592 Oldsmobile jetfire turbo rocket V8 early 60's and Chevrolet Corvairs of the early 1960s. Reading is fundamental! Get R.I.F it pays!🤣
@@crw3673 and just when was the last time that you have seen either one of those examples , cause I have never seen one , and I'm old enough to remember those days . Can we say very limited production numbers .
@@bobbrinkerhoff3592 stop being a hater! You ask for proof and I gave you the cliff notes.😂 You should have looked it up and said wow, you learn something knew every day.
The history of the Oldsmobile was that the engine needed distilled water to run, but most people never refilled the reservoir and hurt the engine.
The history of the Chevrolet Corvairs were that they were rear mounted air cooled engines. That Don Yenko made a race car with. The Corvairs got discounted when a guy wrote a book. "Dangerous at any speed". That book destroyed the corvair reputation and GM discontinued the whole series. Their was a coupe, sedan and van, maybe a station wagon also. That competed directly against the Volkswagen, with their rear engine, air cooled vehicles.
By the way I just turned 51! So this was before my time.😂
Had a '91 buick skylark with the 2.5 iron duke. You couldn't kill it.
Have had two of these, in one car. You can absolutely blow them up, in a Fiero. Thing looks like it came straight out of a tractor.
1985 Citation, bad head gasket at 60k Built my first Ram Air 400 when I was 17 that had 10.5 to 1 compression and no head gasket failures.
My mom bought a Cutlass Ciera with an Iron Duke in 1985.
0.40 - whilst looking to see what other GM divisions were doing at the time, lucky they either didn't look hard or just ran away when they saw the ridiculous Starfire 4 that Holden was just about to gift to the nation :D
I had one in my 1986 sea ray boat.
The problem this engine had as fwd at first was the power steering pump mounting brackets that would bent out of line causing belt wear. The engine would find use again in the fwd A-body in 1982 Cierra, 6000, Century.
If a person added an electric water pump to the 2.5 they would add a good deal of hp by cutting the cooling fan. There is not much way on the 1992 2.5L to actually do anything to the block or head that will accommodate more horsepower on those versions. The cams aren't out there for those 2.5L TBI versions, and hard to get the correct lift cam. Most likely get 120Hp out of it tops all worked over with porting and everything for the price of a custom ground cam to boot.
I bought a 92 in 99 that was overheated and thought I could stock part overhaul the engine and everything would be fine. Ran into issues with the machine shop and more headaches than an engine could be worth. Not money wise. Parts wise. Almost sure the machine shop rebuilt the good head with the overheated rocker arms and valve springs off of the bad head we had checked. 3 cylinders would read 85lb at times, and then retest 130lb. Only 1 cylinder was consistent at 150 lb.
First thought was the new lifters, not that. Let it break in, but she was stubborn and rough to idle cold and had a feedback in the steering column that caused the dash gages to increase their gauge as the system current got higher. Rev the engine and the gas hand would go from a quarter to 3/8 tank and back to 1/4, just flipping the throttle.
The problem with the engine was the "stock" rocker arms had bent themselves some and the springs had gotten cooked by the old man that owned it, when I bought it for $500. Good deal until getting into all that issue with the rockers getting mixed up.
I had a 1970 350/300 way back then to insert right into the s10 when I bought it. Shame I didn't. I could have re-ringed and threw an entire set of bearings in the 350 for next to nothing.
Why anybody would expect silence and smoothness from a 4 cylinder is beyond me.
@Jazc-mp889 Some very small ones maybe, but we didn't make any cars that were small enough and light enough for those engines. This engine was fine for what it was intended to be.
@Jazc-mp889 Most of the people complaining about roughness and vibration are talking about the course "buzzing" feeling at speed more than a rough idle. Many cars of the 70s and early 80s had a less than silky smooth idle due to having to meet EPA mandates - lean idle mixtures and retarded ignition timing were required, and a lean idle mixture often means a rough idle, as does retarded timing, even in a V8. Fuel injection when a long way toward fixing that, computerized ignition systems did the rest, but both came with a downside - you often can't repair such cars at home in your driveway, you have to bring them to a shop if something is amis.
I started out as a mechanic in 1991 and worked on many of these. they have a distinctive cranking rythem that you can hear across the shop. When distributorless ignition came in it was a real pain changing the crank sensor because it was mounted on back of the engine behind the coil pack. I replaced many timing gears as well. those were the days for a mechanic, the cars were really junk.
I loved my cast iron duke but in an A body it was a loud dog for sure.
Owned two or three A-bodies with this engine. It was resonably responsive in those, and very dependable. Didn't EVER belong in a Camaro/Firebird, that is when the HATE started +
I'm a big fan of gm tbi.
What do you find great about toilet bowl injection (tbi)?
@@Santor- You never drove one? They run as good (better, IMO) as a carburetor.
@@Santor- GM Throttle Body injection was the best in the 80's. Very reliable, easy to diagnose, and parts were cheap. It was more advanced than the Bosch mechanical injection, but was great for things like cavaliers, grand ams, etc.
It was also great when the chevy v8's got throttle body injection. They ran great, lasted forever, and had very little problems.
It was the perfect answer to what was needed for getting started in fuel injection. The Ford system with it's crazy testing system, and chrysler map sensors, were over engineered junk. Others made more power (significantly for the Ford 5.0/302), but they were very problematic for a small amount of power gain.
Their ignition performance is nothing to sneeze at either , some having a plug gap of .080 on the high side and plenty around .060 as typical.
These things always sounded like they were on the verge of rod knock but i do find some of their engineering decent ,like the ignitions.
Yup. Had a '93 Suburban 5.7 with TBI. Smoothest running, most reliable vehicle I've ever owned. Kind of missed the secondaries on the Quadrajet opening up at full throttle, but tbi was more reliable.
I had an GMC S-15 with a manual transmission in one and it was adequate. NVH was awful. MPG was good. At idle it sounded like there was something loose in side the engine like it rattled but that was its character.
You can’t call an engine “bad” just because it’s a “dog”. It might be the wrong engine for the application but that doesn’t make it a bad engine. The Iron Duke was certainly the wrong engine for most of the applications it was used in but it was a good engine.
Wow every comment is positive about the iron duke 2.5. Bought a new 87 celebrity with the duke. Was junk from day one. Couldn't move the car well. It would stall out in reverse w/ac on and dealer could never fix it. Always had it in for repairs whether it was a power steering belt issue, not starting when below 50°F, trans not shifting, tps problems, the list goes on. Hated that 2.5
It's possible the problems that the quad-4 had was why it was kept in production so long. The time of people who bought Cutlass Cieras and Centuries we're demographically more interested in simplicity and reliability. If they were interested in new technology they would have bought a w body car instead so I can understand why they would stick with the iron Duke. I don't see as much a problem with the iron Duke in the N cars as much as I do with a Camaro/ firebird. Considering how it was configured, it encouraged them to buy the V6 for not that much more money and clearly that's what GM wanted them to buy anyhow.
I speak from experience about the demographics on this as my father had one and many family friends had theirs who were very careful with money. They were the type of people that a car is a appliance and nothing more. If you bring up the idea for valves per cylinder You would hear a rant about unnecessary complications, extra maintenance, extra cost, and so forth. Please note, This is not meant as a mockery just as a window into the way they see things. They have some valid points that should be considered more often especially when trying to understand the general public.
Didn't Cosworth make a DOHC head for these,? I believe they did.....I once drove an ASTRO van that came with the Iron Duke and a T4 manual transmission, way cool and surprisingly peppy.
Their biggest mistake was the same mistake all 4 american manufacturers made when they transitioned to 4 cylinders: they didnt account for power drawn by accessories. For example, they often used the same belt driven fans as the v8s. That fan might cost 10 hp to run at 5000 rpm. On a 200 hp v8, that 10 hp parasitic loss isnt noticable. On a 100 hp i4, that 10 hp IS noticable.
Did that Cavalier pictured at 2:55 really have an Iron Duke in it?
Had that in a old skylark, i didnt mind it
Compared to the POS engine that was in the Chevy Vega, the Iron Duke was a great engine. Only Chevy had the Aluminum block engine in their compact, all others got the Iron Duke. Good enough reason to NOT by a Chevy if you wanted a basic small car.
EXACTLY, the IRON PUKES should have been replaced by Quad 4s. If the Fiero had been extended iunto the 89/90years, the Iron pukes where going to be replaced as the base engine with the H/O Quad 4.
There was nothing wrong with the iron duke. It all comes down to how well you take of it and drive it.
Good solid little engine
This is a great engine for a tractor
301 cut in half
If you don't maintain any engine you have problems, rock solid engine. Consumer reports is a joke
I think overall they were pretty good engines. However, they did sound like a diesel engine and that’s due to the fact that they had piston slap or even sometimes in some cases wrist pin knock you could have the engine rebuilt and the noise would go away but only for a short time the post office trucks still have them today in 2024 that tells you they must be pretty good for the most part
Generally very reliable but crude and noisy. Especially prior to the balance shaft introduction in the late 80s.
Its only problem was that it was too good. NEVER let me down in any vehicle one was in. My only problem was recognizing when GM did somethin right, if I would have I'd still be driven the '88 S-10 and Ida kept the one outa the other '88 for a colorado.
Stout little engines. We found them to be durable and able to handle abuse offroad. Not powerful, but they would start in the cold and operate under harsh conditions. Comparisons to agricultural engines is very fair and in this case, even flattering.
It's bad. But it could be a lot worse. It's very reliable, even if it's noisy and totally gutless.
They didn't call it the iron puke for nothing. Low compression, low power, and about as exciting as a plain cheese sandwich. Forklifts had more power.
The iron duke was a good motor however it was underpowered in most cars GM put it in at 98 HP and 134 torque it couldn't move much....but they worked good in boats and had a few of them
@2:50, I don't think these were ever in the "J" cars, such as the Cavalier. Really unrefined engine, but there were zillions of them made, and millions still on the road.
You internet types need to quit. This was in no way hated like that. It was the Vega engine that was one of the most hated GM engines, not this puppy.
THIS IS ABSOLUTELY TRUE. THE VEGA ENGINE WAS THE AWFUL ENGINE THAT WORE OUT AT 50,000 MILES. THE IRON DUKE WAS THE REPLACEMENT FOR THAT ENGINE, AND IT WAS MUCH MUCH BETTER AND WAY MORE RELIABLE.
@@sasz2107 They must be too young to have experienced that horrible Vega engine.
I have an old one and I say it sounds like a sewing machine...but then again, the rockers are probably loose...keep 'em flying...
It should have never been offered in the Fiero. Otherwise, not a bad little engine in my experience.
They just shit oil everywhere. How many Burned up Fieros did we see? Too many. Gutless, but if you kept oil in them they would take you all the way to the fire. Hated working on them because we had to pressure wash them before doing any work. The balls GM had to put that boat anchor in a Camaro. I test drove an Iron Duke powered Camaro in the mid 1980s for a brake concern and thought the cat converters were clogged because it was so slow.
EDIT: Smokey Yunik did some development work on a turbocharged Iron Duke.
These engines were gutless turds, but they were reliable as hell.
I think GM should have put a turbo on it.
I didnt hate it. One could get it in a canaro too. You could race vanagons, and win. Only shane is one couldn't get it in Cadillacs, Caprice and K5 Blazer's. Not even the Corvette. Solution was to buy a used chevette and transplant the 4 from that.
Compared to the reliability and drivability that Toyota and Honda were offering in their 4 cylinder engines of the same time period the Iron Duke was garbage. I think the engine was more like Iron Dookie and I worked on plenty of them as a mechanic.
Click bait. You dont know what you are talking about. One of the most durable and reliable gm engines. I had two citations w 2.5 litre iron dukes. Never touched them. Owned these cars for 8 years.
Even Astro vans got this engine
They should have turbocharged them. Should have teamed up with Garrett or something and turbocharged them
A rude, crude, oil leaking, timing gear knocking, head bolt breaking, exhaust manifold cracking NVH disaster. TBI, DI and the balance shaft were lipstick on a pig. The later LLVs used the 2.2 from the J boxen.
I have the newer 2.2 in my 94 s10 and I’ve always thought it was a noisy and harsh engine… can only imagine the iron duke experience
It’s miserable for performance, but it’s an even more miserable task to try and kill an iron puke
I've had multiple cars and trucks with his motor!! All had over 300xxx on them one had 417xxx on it so say whatbu want to I've love this motor with a 5 spd behind it
They are underpowered, but I have seen them come through the shop with 350k miles on them
This motor was not fit to be installed in anything. Maybe it worked in the Chevy Citation until a more modern replacement that was competitive with the imports unfortunately not. It was put in just about everything and GM paid the price.
This entire thing is totally bogus, I have never known anybody that didn't love this engine, our family had plenty of them, on the noisy side, that being said one of the best 4 cylinders ever made, they would tow a load just fine, run for hundreds of thousands of miles, decades, the very best thing, the now known superior pushrod design.
4 inch bore 3 inch stroke.
I wish it was still being made, along with the 3.8 general motors can't build a 4 or 6 cylinder to save itself. Everything modern is trash. The v8's are good 👍
hated for its power output.
Monza was a Chevy model. Not an Oldsmobile