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.
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 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.
@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 flipped a car that had the Iron Duke in it back when I was in tech school in the late 90’s/early 2000’s. I bought a 1984 Buick Skylark from my school’s Spring auction that had one in it and got it for cheap because the top of the engine wasn’t getting oil to it. I took a gamble and believed it was just sludged up. Got it home and ran engine flush through it three times with fresh oil each time until the noise started to die down. Once I verified the top end was getting oil, I put it up for sale and had it sold in about 6 hours. And this was back before online auto selling or marketing sites! That car ran really good, but it and NVH like any other Iron Duke. That was a good little car and I hope it served the guy I sold it to well.
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 were loyal runners easy to maintain and just kept going and going for basic reliable economic transportation in many ways better than even a late model in the same class no worries out of them.
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
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
i had over 435 thousand kms on my 87 iron duke. the last 6,000 kms, it ran with a cracked head and using pepper to plug the leaks. the engine was in my 87 S10 with a t5 manual transmission behind it. i was happy with the engine. only had to put new timing gears in it once.
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.
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.
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.
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 .
This engine really shined in the compact pickup and in marine applications. Without the balance shaft, it was just too thrashy in passenger cars. Early in my mechanic career, I was told about the trick to replace the phenolic timing gear without engine removal. That made me a ton of money at flat rate.
@gregorymalchuk272 The cam gear, while keyed, was a press fit to the camshaft. You could pull it off, but there was no way to reinstall it. The official service method was to remove the engine and rocker train with the engine upside down and pull the cam out to press the new gear on. F THAT. The trick was to use the nicely machined dimple on the the end of the cam as a center pilot to drill a hole into the end of the cam. Tap it to 3/8" and use a p/s pulley installer to press the new sprocket on to the cam. Even faster was to put the replacement aluminum sprocket into the oven for an hour and give the end of the cam a few blasts of freon. The sprocket would slide on with a gentle tap.
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...
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.
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 one of the improved dukes in my first car and it was definitely a reliable engine. Uninspiring and boring, but reliable is about all i remember about those late iron dukes that seemed to be in everyone's GM's.
@@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 ) .
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
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
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.
Dad had one in his 78 Pontiac sunbird with 4 speed stick. Solid machine took neglect and abuse dad wanted a trans am and drove it hard. Then had this motor in my driver training car, an 85 cutlass Ciera brougham. Smooth car excellent for a new driver but always have fond memories hearing it fire up and listening to characteristic idle while our teacher explained the days driving lesson. Have since owned several and our family had the century wagon an 86 with it. Much better than the Chrysler k cars and theirs super slow 2.2 motors which popped head gaskets.
My first new car was an 86 Pontiac 6000 with this engine and a three speed automatic. Pluses: great mileage, lots of torque (relatively speaking of course) Weaknesses: course feeling engine from new, loud piston slap every morning after 30k miles. Prone to pinging (pre-detonation) as it aged. Farm implement is a fair description both good and bad.
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
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.
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 1987 Buick Century with iron duke, it was a pretty reliable engine. But it was noisy, and was a gutless wonder. I owned it for about six years, and was still running fairly well when i sold it. Nohing else really bad to say about the iron duke, other than it was slow and loud, but it got me from point A to point B and back.
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
I was a first time new car buyer and drove a Chevrolet Mona with an Iron Duke before buying a ‘78 Ford Fiesta. Apples and oranges but both were 4 cylinder cars with pretensions of sportiness. The Monza was horrible, rough noisy and heavy while the Fiesta drove like something i would consider making payments on. But the real embarrassment for the Iron Duke came much later in 1984 when they shoehorned it into the Pontiac Fiero. Everyone knows the story with the 1 quart smaller oil pan and the propensity for oil consumption leading to thrown rods and roadside fires. That spectacular failure in the engines most notable application really cooked the Duke’s reputation.
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.
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...!😕
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.
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.
I bought a 1984 Fiero out of the showroom, had it for 14 years. Engine was reliable but I always felt it was nowhere near powerful enough for the Fiero. Pontiac finally got the Fiero right in 1988 with the fastback and V6 but it was too late. If they'd done that from the start, they would have had a winner.
Knew several people that owned various vehicles with this engine and no hate was ever thrown around. I didn't find out the F-Bodies even offered it until many years later because I had never seen one and still haven't. Tractor engine is about right though as far as describing the sound. More pedal meant more noise and not more power. Quite easy to work on nonetheless.
Excellent little video! Unlike you, I am definitely old enough to have been a shopper in the 70s 70s and 80s. This thing sounded so horrible, especially compared to all of the Japanese brands. GM tried to cheapen out and they paid the price in the end run. I can tell you is a car lover in the mid 80s. We were wondering what was wrong with GM engineering that they couldn’t seem to come up with a decent engine GM deserved to lose market share, it’s so sad but so true thanks for sharing this!
I believe the iron duke killed the Fiero as it's only offering in the first two years. Some would have be sold that way. Most would have gone for the six cylinder . The Fiero just needed an engine that could live up to the performance it was capable of. Then by the time the Quadfour was available the Fiero could have had enough sales to make the switch worthwhile and the Fiero could have gotten the engine it deserved. And the midsized cars should have gotten the smoth and reliable six ( fairly fuel efficient too) that GM already had . GM's concern keeping the Corvette protected was unfounded. I believe a potential Corvette buyer was going to get a car with a V-8 anyway. I believe they lost out on a new generation of young first time buyers that ended up getting an import instead.
This was the base engine in the Jeep CJ, also Mercuser 120 & 140 I/O in the latter 70's. Pretty Bulletproof. Still waiting to hear from someone who hated it.
Owned two of them. Very fuel efficient and reliable, but that's it. Later model in the Oldsmobile Ciera had OK power. GM should have gone to Opel of Germany and used their great 2.0 engine of the time.
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.
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.
This was in my Firebird. A FIREBIRD!! A supposed sports car! Even with the 4 speed manual transmission, it was an embarrassment! Yes, the Quad 4 should have been updated with thicker cylinder walls so it didn't blow the head gasket so easily!!
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
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
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.
They required lock tight on the valve cover bolts. Many times had them come in with major oil leaks and the valve cover was just flopping around. On another note: One of GM's terribly designed items, the oil sending unit. (The sensor for oil pressure) The variable version or just the dummy light version, these things have destroyed more engines than... uh .....3.1 v6 intake gaskets, even those cars suffered a cruel fate because of these sensors blowing off the engine.
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.😂
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.
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 +
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.
Was it possible to replace the timing gear without removing the engine in any of the transversely mounted Iron Duke powered sedans, like the X, A, or N bodies?
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.
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 believe the origins of the Iron Duke goes back to a Chevy Nova from 1962. GM led the industry in the 50's and 60's but lost it all with inferior products like this engine and the cars it came in. Their attitude was if they built it, the public would buy it. With Japanese competition and the rise in oil prices, the public started to try alternatives to GM and liked them. The 4 cylinder engines from the Iron Duke to the present day offerings are not as good as what Toyota or Honda has been producing for the past 2 decades.
I think people need to stop complaining and hating on this engine and start looking at what was RIGHT with it. I have had nothing but good luck with these engines. NOTHING EVER BREAKS ON THESE ENGINES. I had one go 367,000 miles, and another go 225,000 miles without ever needing to be rebuilt. They are very good on gas also. I have owned 3 cars with one of these engines. And it is not true that they are all noisy and sound like tractors. If you have the opportunity, find one from a 1980 or 1981 X car. They are quiet! I know because I had one. It was not at all as noisy as the ones that came later - which is not something I can explain. That was just how it was. I observed this on other 80 and 81 X cars when they were still commonly around. The gear on gear design lasts for YEARS. There is no way an engine with a timing belt or even an engine with a timing chain could ever last as long. I only had the timing gear strip out once on one of them, and it went 357,000 miles before it finally gave out. And when it did give out, it's a non-interference engine, so there were no bent valves or pushrods or anything like that. I had one from 1981, one from 1984, and another from 1990. The 81 had a carburetor, the 84 had the first generation TBI unit, and the 90 had the second generation TBI unit. The 81 was the quietest of the 3. The 81 and the 84, which did not have balance shafts, had a very slight vibration at idle that I'd notice in the steering wheel - but it was slight. The 90 did not have this, I believe because of the balance shafts. However, this engine did have more of a "hum" to it, where you'd notice the engine noise mainly at idle or on heavy acceleration. One thing I found was that if my exhaust system was in good shape and had no leaks or any kind, the engine was much quieter. i found that the exhaust flange gasket would sometimes have leaks, and if exhaust gas leaked here, the engine was much louder. Every so often I'd need to replace it and it would quiet it back up. A friend drove my 81 and told me he thought it was a V6, he was very surprised it was a 4 cylinder. My neighbor heard by 84 running and told me he was surprised how quiet the engine was in it. The 90 was he longest lasting and most trouble free. It was so simple, there was literally nothing to break on it. They aren't woefully under powered. They are a LITTLE underpowered. There are also things you can do to help them have more power. It's unorthodox, but you can disconnect the EGR valve, and if it doesn't ping on acceleration, you'll have more power. If it does ping you'll have to leave it connected. They really could have dialed in the amount of EGR exhaust gas that was recirculated - it's too much and it cuts the power too much. They did switch from a vacuum operated EGR valve to a backpressure EGR valve at some point during production. In my experience they both apply too much EGR. The good - they last forever and never break. They also get really good gas mileage. Easily well over 30 on the highway. I regularly got 33 mpg highway and these engines did not have the benefit of overdrive transmissions to help them do better - only the torque converter clutch starting in about 83. So the bad is they are a little underpowered and they are a bit noisy. So what? Get over it. A lot of Japanese car engines were also underpowered at the time. And the noise - make sure your entire exhaust has no leaks and it will help quiet it down. Could GM have done better and made them quieter? Yes, I think so, I don't know why they didn't try harder. But as I've said the early 80s ones really were quieter than those that came later. By the way, the J cars (Cavalier et al) NEVER had these engines. They had 1.8, 2.0. and 2.2 L engines, but never the 2.5L. You said they shouldn't have put them in the A body cars. Well, they did it because the government fuel economy regulations at the time demanded it. It looked like gas was going to get ever more expensive, and fuel economy regulations were going to get stricter. You said don't put them in the 80s F body cars. They only did that in 82,83,and 84 on the most basic cars! Hardly any of them got them. The great majority had the 2.8 V6. I honestly feel people just loved bashing American cars during this time period. There was nothing anyone could do about driving a 70s V8 which got poor fuel economy but was smooth, and switching over to a fuel efficient car in the 80s when the government mandated what kinds of cars the Big 3 could sell! And they're not at all bad! As you said, people love to hate them. So stop hating them and look at what they did well! They're not that bad!
my dad had 81 phoenix with a 4spd and ca smog eqipped 2.5 4cyl carb motor, it did over heat once but then never had any engine failure and the coolant flush left a loose hoose clamp after fixing it, it was good. despite the recalls the phoenix had, and there many, many syncrhos at 14k, diseling and no power, warranty fixed it but demanded we do a smog test by dealer at same service refused to warranty the work, ebrake failed - it rolled out of driveway and almost hit a car when parked, this warrantied 2 nd transmission and flasher unit module almost caused an accident on thanksgiving weekend after going to a dealer they said yeah it's an okc car made before 11/80 it was a vendor problem. It drove to disneyland and grand canyon and got 32 mpg and had to stop with nose upward on the grapevine highway idling for a passing highway patrol escort, wrecker and ambulance, it didn't fail or overheat and had great power and in arizona heat- no hot start issues or overheating in traffic. On the grapevine highway hill we were next to new slantback MARRON AND RED TONED Cadillac Seville with HT400 on the side and it just shut down and made enough smoke and steam under hood TO MAKE look like it just finished a demolition derby and the Cadillac owner was screaming: "its getting towed back to the dealer there's 10,000 miles on the factory warranty and I'm not paying for a new engine while I make car payments. WE NEVER SAID THAT ABOUT THE 2.5 IRON DUKE IN THE PHOENIX. WE LATER BOUGHT THE QUAD 4 IN AN 88 OLDS CALAIS FOR ITS POWER BUT ONE BUYER SPECIAL ORDERED A REPLICA OF OUR CAR BUT INSISTED ON THE NEWER 2.5 FUEL INJECTED IRON DUKE IN THE CAR and WANTED THE OPTIONAL GUAGE PACKAGE WITH TEMP GAUGE NOT JUST WARNING LIGHTS AND ENCOURAGED MY DAD TO DO SAME. HE WAS RIGHT AND HIS SON WAS PONTIAC GM TECH...after the quad 4 lost a headgasket at 89k with care, I'm sure the IRON DUKE CAR WAS STILL RUNNING RELIABLY FOR ANOTHER 80+K MILES WITH NO ENGINE FAILURES. The honda engine was much smoother but in the course of 160k honda miles and service there are two timing belt services that total $5-1100 each, failing to do so can destroy an interferrance engine, as rough as it was that never happened with the 2.5 Iron duke.
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.
@@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.
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.
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
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.
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 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.
I had a few of these in different cars! They never let me down🧐. Not intended to be fast but will get you there & back
Same here! They okay for what they are/were.
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.
Never had a problem with this engine in anything I've owned it in
I flipped a car that had the Iron Duke in it back when I was in tech school in the late 90’s/early 2000’s. I bought a 1984 Buick Skylark from my school’s Spring auction that had one in it and got it for cheap because the top of the engine wasn’t getting oil to it. I took a gamble and believed it was just sludged up. Got it home and ran engine flush through it three times with fresh oil each time until the noise started to die down. Once I verified the top end was getting oil, I put it up for sale and had it sold in about 6 hours. And this was back before online auto selling or marketing sites! That car ran really good, but it and NVH like any other Iron Duke. That was a good little car and I hope it served the guy I sold it to well.
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 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 were loyal runners easy to maintain and just kept going and going for basic reliable economic transportation in many ways better than even a late model in the same class no worries out of them.
I agree.
They always sounded like they had the beginning of a rod knock,even when new😂
Actual rod knock and rod bearing failure about 50,000 miles!
They did, didn't they?
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
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:
ua-cam.com/video/lXlfP_1y2Kc/v-deo.html
But a horrible head
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
i had over 435 thousand kms on my 87 iron duke. the last 6,000 kms, it ran with a cracked head and using pepper to plug the leaks. the engine was in my 87 S10 with a t5 manual transmission behind it. i was happy with the engine. only had to put new timing gears in it once.
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.
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.
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.
I had 2 2.5 iron dukes. Very reliable engine.
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.
I'd take one in a heartbeat over newer engines.
I like the engine.
I have seen these in various forklift brands until very recently so they've still been making them somewhere.
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 .
The Iron Duke idled like a coffee can full of gravel.
This engine really shined in the compact pickup and in marine applications. Without the balance shaft, it was just too thrashy in passenger cars.
Early in my mechanic career, I was told about the trick to replace the phenolic timing gear without engine removal. That made me a ton of money at flat rate.
What was the trick for replacing it with the engine in the car? Was the trick for transversely mounted Iron Dukes like in the X,A, and N body cars?
@gregorymalchuk272 The cam gear, while keyed, was a press fit to the camshaft. You could pull it off, but there was no way to reinstall it. The official service method was to remove the engine and rocker train with the engine upside down and pull the cam out to press the new gear on.
F THAT.
The trick was to use the nicely machined dimple on the the end of the cam as a center pilot to drill a hole into the end of the cam. Tap it to 3/8" and use a p/s pulley installer to press the new sprocket on to the cam.
Even faster was to put the replacement aluminum sprocket into the oven for an hour and give the end of the cam a few blasts of freon. The sprocket would slide on with a gentle tap.
@@keepyourbilsteins That's awesome!
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...
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
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 had one of the improved dukes in my first car and it was definitely a reliable engine. Uninspiring and boring, but reliable is about all i remember about those late iron dukes that seemed to be in everyone's GM's.
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 ) .
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
I HAD ONE IN AN 86 PONTIAC 6000, AND ONE IN AN S10... THEY WERE WEAK AND HAD A DISTINCT SOUND... BUT THEY RAN, AND WERE RELIABLE FOR THE TIME..
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
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.
I like it because you know when the mail man is in the neighborhood.
Dad had one in his 78 Pontiac sunbird with 4 speed stick. Solid machine took neglect and abuse dad wanted a trans am and drove it hard. Then had this motor in my driver training car, an 85 cutlass Ciera brougham. Smooth car excellent for a new driver but always have fond memories hearing it fire up and listening to characteristic idle while our teacher explained the days driving lesson. Have since owned several and our family had the century wagon an 86 with it. Much better than the Chrysler k cars and theirs super slow 2.2 motors which popped head gaskets.
My first new car was an 86 Pontiac 6000 with this engine and a three speed automatic.
Pluses: great mileage, lots of torque (relatively speaking of course)
Weaknesses: course feeling engine from new, loud piston slap every morning after 30k miles. Prone to pinging (pre-detonation) as it aged.
Farm implement is a fair description both good and bad.
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
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.
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.
Had a Pontiac sunbird with one of those engines, never a problem.
I owned a 1987 Buick Century with iron duke, it was a pretty reliable engine. But it was noisy, and was a gutless wonder.
I owned it for about six years, and was still running fairly well when i sold it. Nohing else really bad to say about the iron duke, other than it was slow and loud, but it got me from point A to point B and back.
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
I was a first time new car buyer and drove a Chevrolet Mona with an Iron Duke before buying a ‘78 Ford Fiesta. Apples and oranges but both were 4 cylinder cars with pretensions of sportiness. The Monza was horrible, rough noisy and heavy while the Fiesta drove like something i would consider making payments on. But the real embarrassment for the Iron Duke came much later in 1984 when they shoehorned it into the Pontiac Fiero. Everyone knows the story with the 1 quart smaller oil pan and the propensity for oil consumption leading to thrown rods and roadside fires. That spectacular failure in the engines most notable application really cooked the Duke’s reputation.
A friend of mine had this engine in his Camo EL pickup and it was good
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.
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...!😕
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.
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.
Mine in a s10 was fantastic.
I bought a 1984 Fiero out of the showroom, had it for 14 years. Engine was reliable but I always felt it was nowhere near powerful enough for the Fiero. Pontiac finally got the Fiero right in 1988 with the fastback and V6 but it was too late. If they'd done that from the start, they would have had a winner.
1980 Monza- bulletproof and reliable, many good memories..
Knew several people that owned various vehicles with this engine and no hate was ever thrown around. I didn't find out the F-Bodies even offered it until many years later because I had never seen one and still haven't. Tractor engine is about right though as far as describing the sound. More pedal meant more noise and not more power. Quite easy to work on nonetheless.
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.
Excellent little video! Unlike you, I am definitely old enough to have been a shopper in the 70s 70s and 80s. This thing sounded so horrible, especially compared to all of the Japanese brands. GM tried to cheapen out and they paid the price in the end run. I can tell you is a car lover in the mid 80s. We were wondering what was wrong with GM engineering that they couldn’t seem to come up with a decent engine GM deserved to lose market share, it’s so sad but so true thanks for sharing this!
Is this the same as used in Opels? Then as 1.9 and 2.0s.
Did that Cavalier pictured at 2:55 really have an Iron Duke in it?
Another GM 4 was the Starfire 4 in Australia (used in the mid 70’s)
I believe the iron duke killed the Fiero as it's only offering in the first two years. Some would have be sold that way. Most would have gone for the six cylinder . The Fiero just needed an engine that could live up to the performance it was capable of. Then by the time the Quadfour was available the Fiero could have had enough sales to make the switch worthwhile and the Fiero could have gotten the engine it deserved. And the midsized cars should have gotten the smoth and reliable six ( fairly fuel efficient too) that GM already had . GM's concern keeping the Corvette protected was unfounded. I believe a potential Corvette buyer was going to get a car with a V-8 anyway. I believe they lost out on a new generation of young first time buyers that ended up getting an import instead.
This was the base engine in the Jeep CJ, also Mercuser 120 & 140 I/O in the latter 70's. Pretty Bulletproof. Still waiting to hear from someone who hated it.
Owned two of them. Very fuel efficient and reliable, but that's it. Later model in the Oldsmobile Ciera had OK power. GM should have gone to Opel of Germany and used their great 2.0 engine of the time.
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.
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.
I had one in my 1986 sea ray boat.
Had one in a 1986 S10 pickup. Ran it for 368987 miles on it. Engine out lasted the rest of the truck..
This was in my Firebird. A FIREBIRD!! A supposed sports car! Even with the 4 speed manual transmission, it was an embarrassment! Yes, the Quad 4 should have been updated with thicker cylinder walls so it didn't blow the head gasket so easily!!
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
Had a '91 buick skylark with the 2.5 iron duke. You couldn't kill it.
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
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.
They were slow from the factory but GM had good race parts for it. It had potential.
My mom bought a Cutlass Ciera with an Iron Duke in 1985.
They required lock tight on the valve cover bolts. Many times had them come in with major oil leaks and the valve cover was just flopping around.
On another note: One of GM's terribly designed items, the oil sending unit. (The sensor for oil pressure) The variable version or just the dummy light version, these things have destroyed more engines than... uh .....3.1 v6 intake gaskets, even those cars suffered a cruel fate because of these sensors blowing off the engine.
I loved my cast iron duke but in an A body it was a loud dog for sure.
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.😂
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.
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.
Had that in a old skylark, i didnt mind it
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 +
The 2.2 Ecotec that came out in 1999, is way quieter and smoother than the old 122 2.2, Quad 4’s, and this 2.5 iron duke.
The 2.5 was 1/2 of the Chevy 305. Used same pistons, rods, rod & main bearings
* four inch bore, 3 inch stroke.
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.
There was nothing wrong with the iron duke. It all comes down to how well you take of it and drive it.
Oh, And that fiber cam gear that stripped teeth off. I worked on many back in the 80' and 90's. at a GM dealership in Michigan.
Was it possible to replace the timing gear without removing the engine in any of the transversely mounted Iron Duke powered sedans, like the X, A, or N bodies?
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.
Good solid little engine
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 had one in a 1981 citation. If i ran anything other than 93 octrane it would knock going uphills.
I believe the origins of the Iron Duke goes back to a Chevy Nova from 1962. GM led the industry in the 50's and 60's but lost it all with inferior products like this engine and the cars it came in. Their attitude was if they built it, the public would buy it. With Japanese competition and the rise in oil prices, the public started to try alternatives to GM and liked them. The 4 cylinder engines from the Iron Duke to the present day offerings are not as good as what Toyota or Honda has been producing for the past 2 decades.
I think people need to stop complaining and hating on this engine and start looking at what was RIGHT with it. I have had nothing but good luck with these engines. NOTHING EVER BREAKS ON THESE ENGINES. I had one go 367,000 miles, and another go 225,000 miles without ever needing to be rebuilt. They are very good on gas also. I have owned 3 cars with one of these engines. And it is not true that they are all noisy and sound like tractors. If you have the opportunity, find one from a 1980 or 1981 X car. They are quiet! I know because I had one. It was not at all as noisy as the ones that came later - which is not something I can explain. That was just how it was. I observed this on other 80 and 81 X cars when they were still commonly around. The gear on gear design lasts for YEARS. There is no way an engine with a timing belt or even an engine with a timing chain could ever last as long. I only had the timing gear strip out once on one of them, and it went 357,000 miles before it finally gave out. And when it did give out, it's a non-interference engine, so there were no bent valves or pushrods or anything like that. I had one from 1981, one from 1984, and another from 1990. The 81 had a carburetor, the 84 had the first generation TBI unit, and the 90 had the second generation TBI unit. The 81 was the quietest of the 3. The 81 and the 84, which did not have balance shafts, had a very slight vibration at idle that I'd notice in the steering wheel - but it was slight. The 90 did not have this, I believe because of the balance shafts. However, this engine did have more of a "hum" to it, where you'd notice the engine noise mainly at idle or on heavy acceleration. One thing I found was that if my exhaust system was in good shape and had no leaks or any kind, the engine was much quieter. i found that the exhaust flange gasket would sometimes have leaks, and if exhaust gas leaked here, the engine was much louder. Every so often I'd need to replace it and it would quiet it back up. A friend drove my 81 and told me he thought it was a V6, he was very surprised it was a 4 cylinder. My neighbor heard by 84 running and told me he was surprised how quiet the engine was in it. The 90 was he longest lasting and most trouble free. It was so simple, there was literally nothing to break on it. They aren't woefully under powered. They are a LITTLE underpowered. There are also things you can do to help them have more power. It's unorthodox, but you can disconnect the EGR valve, and if it doesn't ping on acceleration, you'll have more power. If it does ping you'll have to leave it connected. They really could have dialed in the amount of EGR exhaust gas that was recirculated - it's too much and it cuts the power too much. They did switch from a vacuum operated EGR valve to a backpressure EGR valve at some point during production. In my experience they both apply too much EGR. The good - they last forever and never break. They also get really good gas mileage. Easily well over 30 on the highway. I regularly got 33 mpg highway and these engines did not have the benefit of overdrive transmissions to help them do better - only the torque converter clutch starting in about 83. So the bad is they are a little underpowered and they are a bit noisy. So what? Get over it. A lot of Japanese car engines were also underpowered at the time. And the noise - make sure your entire exhaust has no leaks and it will help quiet it down. Could GM have done better and made them quieter? Yes, I think so, I don't know why they didn't try harder. But as I've said the early 80s ones really were quieter than those that came later. By the way, the J cars (Cavalier et al) NEVER had these engines. They had 1.8, 2.0. and 2.2 L engines, but never the 2.5L. You said they shouldn't have put them in the A body cars. Well, they did it because the government fuel economy regulations at the time demanded it. It looked like gas was going to get ever more expensive, and fuel economy regulations were going to get stricter. You said don't put them in the 80s F body cars. They only did that in 82,83,and 84 on the most basic cars! Hardly any of them got them. The great majority had the 2.8 V6. I honestly feel people just loved bashing American cars during this time period. There was nothing anyone could do about driving a 70s V8 which got poor fuel economy but was smooth, and switching over to a fuel efficient car in the 80s when the government mandated what kinds of cars the Big 3 could sell! And they're not at all bad! As you said, people love to hate them. So stop hating them and look at what they did well! They're not that bad!
my dad had 81 phoenix with a 4spd and ca smog eqipped 2.5 4cyl carb motor, it did over heat once but then never had any engine failure and the coolant flush left a loose hoose clamp after fixing it, it was good. despite the recalls the phoenix had, and there many, many syncrhos at 14k, diseling and no power, warranty fixed it but demanded we do a smog test by dealer at same service refused to warranty the work, ebrake failed - it rolled out of driveway and almost hit a car when parked, this warrantied 2 nd transmission and flasher unit module almost caused an accident on thanksgiving weekend after going to a dealer they said yeah it's an okc car made before 11/80 it was a vendor problem. It drove to disneyland and grand canyon and got 32 mpg and had to stop with nose upward on the grapevine highway idling for a passing highway patrol escort, wrecker and ambulance, it didn't fail or overheat and had great power and in arizona heat- no hot start issues or overheating in traffic. On the grapevine highway hill we were next to new slantback MARRON AND RED TONED Cadillac Seville with HT400 on the side and it just shut down and made enough smoke and steam under hood TO MAKE look like it just finished a demolition derby and the Cadillac owner was screaming: "its getting towed back to the dealer there's 10,000 miles on the factory warranty and I'm not paying for a new engine while I make car payments. WE NEVER SAID THAT ABOUT THE 2.5 IRON DUKE IN THE PHOENIX. WE LATER BOUGHT THE QUAD 4 IN AN 88 OLDS CALAIS FOR ITS POWER BUT ONE BUYER SPECIAL ORDERED A REPLICA OF OUR CAR BUT INSISTED ON THE NEWER 2.5 FUEL INJECTED IRON DUKE IN THE CAR and WANTED THE OPTIONAL GUAGE PACKAGE WITH TEMP GAUGE NOT JUST WARNING LIGHTS AND ENCOURAGED MY DAD TO DO SAME. HE WAS RIGHT AND HIS SON WAS PONTIAC GM TECH...after the quad 4 lost a headgasket at 89k with care, I'm sure the IRON DUKE CAR WAS STILL RUNNING RELIABLY FOR ANOTHER 80+K MILES WITH NO ENGINE FAILURES. The honda engine was much smoother but in the course of 160k honda miles and service there are two timing belt services that total $5-1100 each, failing to do so can destroy an interferrance engine, as rough as it was that never happened with the 2.5 Iron duke.
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.
This is a great engine for a tractor
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.
If you don't maintain any engine you have problems, rock solid engine. Consumer reports is a joke
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.
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