I recall several friends back then having this engine and it proved to be pretty durable.

I was a fleet mechaic for many years. Loved the 'Iron Duke', sure it was crude but very reliable, easy to work on and very inexpensive to operate.

I loved this engine. It was noisy because the cam was gear driven. It was bullet proof.

I’ve had several iron duke engines in S10’s and found the engine to be quite reliable. Easy to work on too.

The GM iron duke was one of their better engines back then . Easy to repair , long lasting & fairly efficient on fuel . The post office still uses them

GM sold millions of Iron Duke powered cars. Everybody who bought one knew about the crudeness and roughness before they paid for it. I'd save the "worst" designation for engines that were prone to giving their owners nasty, expensive surprises.

My 1982 2.5 L iron duke has 300k miles with good compression on three cylinders and #4 by the firewall runs 10 to 15 percent lower. I suspect the head gasket is going since it tends to foul the #4 plug a lot more. The valve cover has never been removed and i bought the car new in 1982.

I had a '87 Chevy Celebrity I bought off a friend of mine years ago for $500 as a back up car. When I got it, I know it had over 170,000 miles on it. I drove it around for awhile and it actually ran when the head gasket let go. My buddy and I pulled the head, took it to a machine shop, got a new head gasket, head bolts, and put it back together and it ran perfectly. That old 2.5 wasn't a powerhouse and wasn't refined, but it NEVER left me stranded and ALWAYS started. The old "Iron Duke" was reliable and I wouldn't run away from a vehicle powered by it (especially the later years with the serpentine belt).

Another gem. My dad's brand-new for '86 Olds Cutlass Calais had this engine. In 10yrs the car just about fell apart, no paint, plastic interior disintegrating, but that Iron Duke kept on clattering 🤗

The worst thing about the iron duke was the fiber timing gears. That’s why it was so noisy. Those timing gears could be replaced with steel parts.

I've said it before, and I'll say it again, you could have done a lot worse in the 80's than an Iron Duke. Of course that probably has more to do with there being so many bad engines in the 80's than the Iron Duke being a good engine.

A straight 6 cylinder engine is still the best design of anything yet.

We ran one for years in a mid eighties Buick Century taxicab - almost ideal in that use, went huge numbers of miles, reliable & economical.

The auto parts store I first worked at had a 1977 Pontiac Astre wagon delivery car. It had the Iron Duke. It took almost 80,000 miles of delivery abuse (regular visits to redline, minimal maintenance, oil changes maybe once every 10,000-12,000 miles, probably one new set of plugs, not much else). It finally threw a rod one cold (10 degrees Fahrenheit) morning when we were warming it up for the day, running on cold idle (1700 RPM or so). The rod went down through the oil pan. There wasn’t 2 quarts of spilled, black as sin engine oil on the ground. I think it did pretty well durability wise considering. It was definitely noisy and rough.

Had this engine with a manual in a 79 Sunbird (a RWD Monza rebadge back then), when I was a teenager in 1989. Still one of the best and most reliable cars I've ever had. What it lacked in speed, it made up for with impressive clutch-dump burnouts.

If anyone can imagine the sound of a mail truck (Grumman LLV), those still run the iron puke to this day. Guess they couldn't be all that bad!!

The Iron Duke should’ve been a Soviet Engine.

I've owned several vehicles with that 4 banger. With oil changes, most of the engines outlasted the rest of the car. The biggest problems they had was the crappy complicated carbs and then early generation fuel injection. Not to mention the dozens of low-quality vacuum hoses that were prone to crack and leak. It's not fun when a 4 banger is idling on 3 cylinders at stop lights.

I had a 1991 Pontiac Grand Am; best trouble free car I've ever owned. Drove it over 200,000 miles and sold it to a friend of mine. Headliner never sagged and it had the original fuel pump and the Tech 4 2.5. Mine had V belts but it ran smooth for the most part - had plenty of power to always spin the p205 65 r 14 tires off the line and had plenty of passing gear power all the way up to 80 mph. After 80 it would stay in 3rd but still pulled pretty good for what it was. The timing gears were very quiet until one day I beat on it pretty hard at 40,000 miles then they started making the normal 2.5 gear drive rattle.

I came up in the 80’s. I’m a tech and I remember those engines. I agree with you. They were reliable and long lived, also unrefined. I didn’t care for them because they were overshadowed by engines like the 3800.

Completely disagree on the Iron Duke being one of the worst engines of all time. The engine was used in many GM cars and trucks of the time, industrial, and marine applications. We had one in a 1989 Buick Century for many years and a couple of hundred thousand miles. The engine was pushed hard and never had any sort of issues or problems and got excellent fuel mileage. Every person tells me the same about how reliable the engine was. In my opinion this engine possibly could be considered to be on the best GM engines of all time list.

1990. I was six and my parents had just split up. Things were ugly and we didn't have much money. After the split my mom needed a decent vehicle. Her and my grandpa went down to a local used car dealer and purchased a two tone brown and tan 1984 two door S10 Blazer. 4wd with a manual. Cute little thing. I hated it because it wasn't the k5 Blazer I had grown up in though. However, I look back with so much fondness for that little iron duke powered Blazer today. I just can't help but smile everytime I think of it, or see it! Yes it's still around.. My mom drove that little thing nearly through my highschool years. So you can imagine all the school sporting events that she went to over the years. It finally ate a head gasket and at the time, I didn't have the knowledge or knowhow to do anything about it. So she sold it in favor of a 94 two door s10 Blazer. The guy who bought it rebuilt that iron duke and I still see him from time to time. I always ask him how it's getting along and he always gives me all the updates on it. I've requested that if he ever decides to sell it that he give me a call. He graciously agreed to that. It had to have had a couple hundred thousand on it when the head gasket went so I can't imagine now. Funny that a discussion of the 2.5 iron duke can bring me both good and not so good of memories. All I know is that that little blazer never stranded us even once in all those years. Great video as always. *Edit: I realized the first year of the s10 blazer was 83 and not 82 so I had to check with my mom and she said it was a 1984. Just wanted to clarify that.

Hi Adam, for what its worth ive had several iron dukes and always had good service from them.I do agree they were very industrial but they were good for what they were.

Had a few of them in S10s. Ran a company that used them for delivery. Didn't have a lot of problems with them. Couldn't get out of there own way but would easily get over 200k. When they switched to the 2.2L then the real problems started!

Had four iron duke equipped cars including my wife's 1980 AMC Concord. Never a problem outside of normal wear and tear parts. They did all have leaky valve cover gaskets, fixed by the FelPro rubber coated steel version. Still have my '86 Ciera that draws a croud at car cruises with the hood open displaying the Duke in all it's glory. Yes, everyone claims to have owned a car with one in it!

This engine had few internal problems. It was reliable in the later 80s and 90s. Noise was fixed by newer cam and crank gears. It was pretty durable

My folks had an '88 Pontiac 6000, it's what I learned to drive in. I can still hear that engine, it just had this distinct sound. Other than having it eat the cam gear on the highway at 100,000 miles, it was still going strong at 190,000 after dad and I replaced the cam gear ourselves. The body rot was pretty bad on the car by then, I think he got a whopping $100 trade in, but the engine was still running like a watch.

The original 60's and 70's Iron Duke you could not hurt. It was half of a 283 V8 and came in Chevy 2's and other GM cars. I even had one in a 1974 CJ3 Mail Jeep and drove it once a month from Houston,Texas to Shreveport, Louisiana and back for Navy Reserves and drove it every day 150 miles round trip to work for 2 years. Sold it running like a top and the guy I sold it to drove it another 10 years. It had over 200,000 miles without a rebuild.

A guy I worked for back in the 80's got 41 mpg hwy in his Citation with an Iron Duke and a stick. Nuthin' wrong with that.

While a bit crude and noisy I wouldn't call it the worst of all time more like a middle of the road reliable but not too pleasant engine. By 1987 it was smoothed out with balance shafts on the stick shift cars and 1988 with automatic transmission and was a decent engine from that point forward. We used to upgrade the dog bone motor mount to the Moog that was hydraulic and smoothed both the engine idle and transmission shifts. I would call the HT 4100, 5.7 diesel and Northstar engine in its early years as the worst from GM.

My 1983 Omega had an Iron Duke in it. Yes it was noisy and rough at idle, but not bad. Had vapor lock problem due to bizarre fuel injection set up. The rest of the car fell apart, the engine still was OK.

They're slow and ridiculously crude, but they're unkillable. Which is why the best application for them has been in the Grumman LLV mail trucks (essentially a 2wd S-10 Blazer). The tractor-like engine noise pretty much serves as a siren. You can hear them a mile away.

I had one of these engines in an 81 Citation. It had what I believe was called the 2 Barrel Varijet carb. Two issue with the engine, never depress the gas pedal to restart if it was warm (it would flood immediately), which people I let borrow the car found out quickly if I gave them keys after driving it. Also had to change two ignition control modules, but you already have a video on those. Other than those issues it seemed to be bullet proof to a certain level of abuse from a college aged kid.

One of my Uncle's had the EXACT opinion of the Iron Duke as you described. He had a 1977 Buick Skylark with a 350 V8 and in 1982 wanted to trade it in for a new Skylark. Well when he first looked at the new Skylark, he was rather impressed with it, even though it was a good deal smaller than his current car. He was surprised at the roominess of the interior for being a smaller car. He found a 2 door that he liked in the color and options he wanted and went for a test drive. When he started the engine, he changed his mind immediately !!! At idle it shook the whole car so badly he thought the factory put in defective motor mounts. He also said that his Stepfather's John Deere tractor was quieter and smoother running !!! He instead opted for a Buick Century coupe with the V6.

Spot on review. One thing these engines were good for were marine applications. I had one in a mid 80's 17' Sea Ray. It made 120 hp, which was adequate, it was fuel efficient, and extraordinarily reliable. The hull and engine cover did a fairly good job absorbing the noise and vibration. I miss that old boat.

The fiber gear was probably made of phenolic laminate, e.g. Micarta or Tufnol. Ironically, this material is usually selected to reduce gear train noise! The soft gear absorbs the high frequency vibrations that create gear whine. A hardened steel gear would no doubt have lasted longer, and not rattled due to wearing down. Fun fact about phenolic laminates: they can be adequately lubricated by water rather than oil. As a result they are a popular material for propeller shaft bearings on ships.

Cam gear was made from phenolic resin, which was to combat noise. That gear was about the only thing that killed them. It was a good truck engine in my opinion

Many moons ago in mechanic school we used to say, “the iron duke’ll get you to 200k…but not very fast.” My grandparents had an ‘85 Cutlass Ciera for about a year and it was so displeasing that 37 years later a 4-cylinder car is still out of the question!

My Iron Duke has almost 300,000 miles on it never left me stranded anywhere she's finally getting tired due to lack of oil changes the motor pretty worn out lots of blow by nowadays still starts and run every time takes me whenever I got to go right up till this day I'm going to end up doing a V8 swap in my S10 but I will still keep the good old Iron Duke on the side for another project and redo the engine and make her nice and fresh

This engine has delivered half of all the mail to most US houses for 34 years. It's not refined or powerful, but no way is it one of the worse

I thought they were decent engine's but definitely not one of GM's best, I heard they were better than the 2.8 Liter V6's on many early 80's GM vehicles.

Crude and rude - but durable. I had forgotten about the phenolic resin fiber timing gear. The Iron Duke's competitors had a timing belt- which many American owners only bothered to replace AFTER IT BROKE.

I had an S10 with an iron Duke and it was extremely reliable and got decent milage. He 254k miles when I finally sold it and it still ran strong. Honestly I've never heard anyone say a bad word about the old iron duke

I'm from Brazil and I have a Chevrolet Opala, the car that was first equiped with the engine that gave birth to the Iron Duke. Mine is an 89 , carburated and powered by ethanol. This sounds bad but it isn't. Even though we didn't received the "improvements" that the US cars did I really like this engine. It vibrates a lot but if you set the iddling around 700rpm it becomes quite smooth and with a nice exaust it sounds good too. It's not fast but it offers a nice amount of torque which is ideal for city driving and fuel consumption. Also Brazilians used to call it the "sewing machine" because of the distinct noise it makes.

My Dad got a new in April 1979 Chevy Citation. It had that 2.5 4 cylinder and an automatic. I remember the V6 60 degree had a lot more teething problems.

I worked from 81 to 86 in a gm dealership ,I loved the 2.5 mostly because folks seemed to gravitate to the 2.8 v6 now that motor was a genuine pos ,carb with electric controlled jets ,leaking rope type rear main seal ,all for .3 more liters ,

My parents had a 91 Calais with the Duke. It was extremely quiet when brand new. After say 20,000 miles there was a certain clatter associated with it. Like you say it was durable and reliable and economical. When I later got a Calais with the 'upgrade' Quad 4 ... well it was much louder, and hobbled by the 3 speed. The Duke was better than the Quad unless you enjoyed lots of repairs.

i also had 3 different cars with 2.2 TBI engines and they ran a little smoother and didnt have the timing gear clatter sound..... but they were well known for head gasket issues. given a choice i would rather have the cast iron head sitting on the cast iron block. rarely did they have a head gasket issue.

After being a professional technician for 30 years I would respectfully say that anyone who thinks the Iron Duke engine was a great engine apparently has very low standards as far as what constitutes a great engine. It was a waste of good iron and steel.

An Iron Duke will run like poo longer than a lot of newer engines will run, period

Pontiac Fiero 2M4 SE 5-speed here. I'll never forget when people would get into my car for the first time and start up the Iron Duke - the vibration from the back! In some ways, I think it was a great choice given the Fiero's complex cooling system. The iron block and head were very forgiving for overheating. The Achilles heel was Fiero drivers made the mistake of over-revving them. I did tear it apart and rebuild the engine, put another 200,000 km on it after that. I miss my Fiero, and I would only want an Iron Duke in it.

One other thing you didn’t mention concerns the oil filter. This engine was first designed for rear wheel drive applications, and when the engine was turned sideways for front wheel drive, the oil filter was a bear to change, as it was on the backside of the engine with a lot of stuff in the way!

The sound of my youth! An endless stream of X- and A-body cars moaning up the hill in front of my suburban childhood home. The TBI Dukes had an especially distinctive sound.

Best 4-cylinder I ever owned, but then I am also unrefined and crude.

A friend had a Celebrity with the Iron Duke engine. It always was a little noisy until it reached 100.000 and then you could barely hear the radio. I replaced the balance shaft assembly and was as quiet as new. By the time it hit 200.000 the car was very rusty so he decided to scrap it. Before we scraped it we tried to blow it up. We tried for 2 hours on the rev limiter until there was no coolant in it and dumping everything we could find down the throttle body until it finally ran out of gas. We added a little bit of gas we had around and when we started it, it ran like new. I used to call them a tractor engine but I gained a lot of respect for them that day.

Worst engine? Well, I had one with a 4 speed stick and my buddy had an S10 with a 5-speed stick and we both beat the snot out of the things--they would not die. After years of abuse, I sold the car to a buddy that pulled the Duke and put it in a swamp boat. The thing did not burn oil, leak oil, did not leave me stranded and sure, it was rough, loud and socially unacceptable but it matched me. Hmmm, might have done a few "adjustments" to the carb, put a louder muffler, flipped the air cleaner cover and played with the timing to wake it up a bit (cough, cough) It's legal as long as you don't get caught and no sniffers ever violated my tail pipe so no worries. Compared to most of the garbage plying the roadways, the Iron Duke just plugged along. Changing the starter sucked...I did change the distributor cap, new larger radiator and the biggest battery I could cram in when the alternator needed replacement but not bad. To me, worst engine means that the thing is always breaking down--never had that problem. It was a shaker but so was the Toyota 2.4L of the early 80's...as long as you kept the tensioner on that engine stable, it was a good engine also. Never delt with a Duke with a sluch box though, you needed a stick back then if you cared anything about performance so that is what we ran. I'd rather have a shaker that just ran than a smooth engine the leaks oil, coolant, breaks cam belts, eats cams and dies just as the payements end.

I always considered the 2.5 Iron Duke a “decent” engine. The one’s I’ve seen give excellent service were the 2.5’s that got religious oil and coolant changes. To me they sounded like coffee grinders. I had one of these in a 1983 Olds Omega with a 4 speed manual transmission!

My parents had two cars with this infernal loud, slow "buzz bomb" motor, an '84 Omega followed by an '87 Century. The Century was too large a car for this motor, very underpowered. My Mom liked these cars, by my Dad and I did not enjoy these buzz-bomb powered cars. Dad preferred his '76 305 Nova, than his 2.8 liter Celebrity Wagon, which got better highway mileage than the '87 buzz bomb, and was far more pleasant to drive😁

I took my drivers test in my mom’s 79 Pontiac Sunbird coupe equipped with the Iron Duke. I drove it a lot before I bought my first car. We never really had any issues with it. It certainly wasn’t a fast car but thought it ran pretty good for what it was. I remember it was carbureted version. The carb looked like a quadrajet cut in half. It ran about as good as an 81 Grand Prix I test drove that had the Buick 3.8 V6. You can make fun of their low power output but GM made plenty of performance parts for the Iron Duke. Back in the day it was the 4 cylinder of choice for racing. I do remember a buddy of mine had an 82 Firebird with the Iron Duke with a 4 speed manual. It was pretty pathetic. A car that looked that good being painfully slow.

I had an ‘82 Buick Skylark I inherited and drove for a few years in the mid to late ‘90s and remember vividly how rough the engine sounded and the shake that came through the steering wheel at idle just as you described. That said, I never had a problem with it, very reliable. Thanks for another awesome informative video. I also had an 83 Impala wagon, with another possible ‘worst’ contender, the 700R4 transmission. Went through three of them in as many years, with only normal use. Curious if this was common experience.

I'm not even going to watch this video. The 2.5 is one the most durable and reliable engines ever made. I've owned over 25 of them including one in my garage right now. It was bulletproof.

Adam, I wouldn't put that engine in the "worst " category. Crude yes, unrefined definitely, reliable absolutely. Power was an after thought. Early carb models were to say the least gutless wonders, when you floored it all it did was make noise and go nowhere... fast. When they TBI 'd them really kinda of liven them up...Some... Always thought of that engine as GM's way of entering into that era of more fuel efficient, compact car powerplants. The oil embargoes of the 70`s (who remembers when gas prices hit a $1 a gallon in around '78 and people were so shocked) definitely caused a shift in the market, which not only GM but all the domestic manufacturers had to adapt. Just about killed Chrysler. Asian cars along some European cars were taking over. I used to call them the "silicone engines" because of the wide use of GMS. They were oil leakers too.. Like you and many others have said it was used in about everything, cars,pickups, industrial and marine, etc applications. Even other manufacturers used them as well. Probably because of unrefinement and crudness they were cheap to produce. The fiber cam gears were suppose to quiet them down a little, in which they did... for a time, but when they started to wear you knew it. They got loud. There was and still probably available aftermarket steel or aluminum replacements. If the owners had kept up on the routine maintenance, (like any car) oil changes, coolant flushes, etc they were very reliable in which didn't see as many mechanical failures. I think because of the lower power output is one of reasons why that could last so long well over 100K+. They were pretty well build inside, besides the cam gear. Never saw (at least in my area) allot of bottom end failures, mostly the typical issues, oil leaks, cam gears, head gaskets ( mostly due to head bolts breaking on the exhaust side usually between cyl's 2,3.) and occasionally cylinder heads would crack due to severe overheating, because of prolonged coolant leak or sudden loss, stuck closed thermostat, etc. They serviced there propose for the time, very well. The much earlier GM 152 4cyl used in the 60's Chevy ll and Nova models was a great little engine, it to was used in various applications. The ones I remember were mostly in industrial use, portable High volume air compressors, mobile generators and even some smaller forklifts. My work has a Daewoo forklift (made in South Korea) which has that engine, of course propane powered, electronic ignition (Hitachi equipped) it runs great. Makes me wonder if GM had sold off the plans/ tooling to make that engine to Daewoo, I know they were "in bed" together for a while, but that's another story. Thank you Adam for the great video and look forward to seeing more.

We had an '87 Buick Century with this engine. At idle, it could easily be mistaken for a diesel!

So glad i found your channel! I enjoy the basic down to earth 🌎 format! Thank You 😃

Im glad you mentioned the timing gear. Its a noninterference engine so no issue when the gear gave out. Cosworth made a Duke that cranked out 500+ rpms so they had potential.

My greatest issue with this engine was the location of the distributor. Combined with the unreliable nature of the ignition module, you had a nightmare when it came to serviceability. It was obviously related to chevy’s inline six. But when they made the cross flow heads, it placed the distributor under the intake well hidden.

We had a brand new 85 Celebrity station wagon with this engine. It would haul 7 people around(although not a ball of fie) quite well. Drove the car for ten years and never a hiccup!

I had that camshaft gear go out on me in an '88 Cutlass Ciera that I owned while I was in college. This was in late 1996. Even then it was an almost $800 repair at the shop. 😬

If you grew up in the 80's like me, you have definitely either owned a car that had one or at least driven one.

My dad had a 1989 S10 with the 2.5L and it was a good runner. Had two issues heater core blew and the computer went out. We went on many road trips. This truck with a 5 speed would get 30 mpg. Hit the hills in 4th gear and run 65 mph over them. I do remember those 2.5l in GM cars and boy talk about rough.....yikes.

I sold S-10s on a used car lot in the early '90s. GM trucks were our specialty. The only S-10s that I saw over 200,000 miles had the Iron Duke. I saw a bunch of them. The would just run and run and run with minimal maintenance.

I worked at a Chevrolet dealership in the 90's and we used to get a "gravy lick" when a customer would complain of timing gear noise. 4-6 hours warranty time to R&R the camshaft on trucks and 14+ hours on FWD cars so the cam gear could be pressed off and a new one pressed on. Fact is we could chisel off the gear and press on a new one by drilling a hole in the cam, cutting fine threads in it and using a bolt and washer to screw it down on the cam. Durability? Well look at those Grumman post office trucks (they're on S10 chassis) STILL running around the neighborhood. Some of those are over 40 years old and still running the original 2.5L Iron Dukes, some of those with enough miles to go to the moon and back... TWICE!

These things sounded like they came with a factory rod knock. Never knew it was the cam gear. They were damn near indestructible though.

i had a 84 celebrity that had a 2.5 300000 miles very reliable

Pretty cool to see in an hour over 2k views! Great job on this series! 👍👍 Obviously us older gearheads love this stuff on your channel and alot of us were wrenching or owning this old stuff.

Hey Adam, I sure am enjoying your porch chat series, thanks for sharing your knowledge!!! 👍👍

Owned 2 "A" cars with this engine, although gutless and noisy to the point years ago someone asked if it was diesel, very dependable. Decent fuel mileage, in terms of a TBI engine, and very simple to change almost any control on, in car especially. The early fiber timing gear left us stranded once, but my 88 model with balance shaft and silly "in pan" oil filter sat 2 years in a swamp in the back field, has every wire and contol bypassed, has rodent nests all over, still sounds like it did when new, yes I am saving this engine.

You could do a lot worse than the Pontiac 151. It was probably the best gm 4 cylinder up until maybe recently.

my wife and I rented a small buick from alamo rentals in florida to use on vacation around orlando. my comment was the engine sounds like a tractor or someone vigorously shaking a bucket of bolts. the thing did the job ok. my mother had a 1986 celebrity with this engine. it worked fine for many years. a little tractor.

The Grumman USPS vehicle stopped production in 1994, so, every classic USPS truck you see (which, here in MN, is most of them) is 29 years old, or older, and it has an Iron Duke. Constant starts and stops in sometimes, -30F or colder weather, up to over 100F weather. I can't think of any vehicle that has to endure more abuse than mail trucks. The Iron Duke is a real dog, especially in an automatic, but, they do keep going. P.S. This was one of GM's best but most boring engines. Reliability is always paramount, especially in extreme conditions.

An old school, reliable engine, plenty good enough for its day. Was used successfully in many applications, including some CJ Jeeps and inboard/outboard boats. Better low end power than overhead cam 4 cylinders.

Ahh yes the iron puke......

My Uncle had a 1975 Chevy Monza with a 262 V8 and a manual 4-speed. It got 22-25 mpg on the highway. I KNOW because I used it for a month and calculated the fuel mileage myself. Now with an engine like this WHY, WHY, WHY would GM ever even want to develop these half-assed 4 cylinder engines in the first place? It has been my lifelon experience that the small block Fords and Small block Chevys typically are more efficient than the 6 and even 4 cylinder counterparts. Look at all the engineering and production costs GM could have saved just by using the 262 V8 in ALL the cars they put newly designed 4 and 6 cylinder engines in. The V8 design has the best potential for efficiency. Turbocharge a 4 cylinder? NO THANK YOU!

Can anyone help? I’ve removed the fiber camshaft gear(failure). Replaced it with a new aluminum one along with new crankshaft gear. Not realizing using the puller I might have rotated the cam a couple rotations(using impact on puller). After installing new gears. I’ve lined up both timing marks 11 o’clock to 5 o’clock. After lining up TDC and distributor getting hard start and backfire while adjusting distributor. Is it possible I might have installed cam gear out a full rotation? Or should it fire regardless of gear installation as long as marks line up?

The Grumman LLV had the 2.5l from 1987-1992. The last 2 years (1993-1994) was a Chevy 2.2l. The 2.5l had the catalytic converter right under the driver's feet. The 2.2l had it under the tray side. These vehicles have no insulation against the heat coming up through the floor. The 7 digit truck number denotes the year it was made. The first digit is the last digit of the year.

I worked in a full service gas station and repair shop during the early 2000's and I never encountered a single 2.5 that did not have a cracked exhaust manifold

I Love this Channel. Your Best/ Worst Lists are awesome.

I had a 1990 S10 that had the 2.5 with five speed trans and when I got it I was told it had cought fire and he showed me the original intake it had a crack on the bottom between intake runners 2&3 is that a common thing?

I think there was a marine version used in stern drive boats and I think I saw an industrial version recently on a standby backup generator.

I do have some fond memories of the Iron Duke, my former stepmom had a Buick Somerset and it ran forever but WOW that engine was noisy

Had two S10s with the ol duke and 5 speed combo. Both trucks shook bad enough to make the mirrors fuzzy and power was no where to be found, but they were a blast to drive. Couldn’t kill either one, even ran my first S10 low enough on oil (did it twice) that the motor locked up. Let it cool off, added some more oil, and away I went. There’s only two things that will survive a nuclear war. Cockroaches and Iron Dukes.

I have a 1989 S10 with the 2.5L. It's doing just fine. About 209k miles. Still doesn't smoke and burn oil. It's no hot rod, but it works.

We had two cars with this engine. The first was a base Pontiac Sunbird with a manual transmission. The engine suited the small car and price point. It was very reliable. Later in the mid 80's we had a top of the line Olds Cutlass Ciera. The engine in this car was also very dependable, lasting over 200,000 miles, but it's performance and lack of refinement did not match the cars' price point. We later had a number of Buick Centuries who's V6 was more appropriate for the front wheel drive A body platform.

the 2.5 was a terrible choice for the f body. people were expecting more then 85-90 hp and an engine that sounded like a mail delivery vehicle in a firebird or camaro.

Another excellent video! I had a 1984 Celebrity wagon with this engine and concur that it sounded like farm machinery, at least at low RPMs. If I had only known about that idle adjustment trick! The engine itself gave me no grief on that car, other than the cheap, electrical conduit exhaust manifold cracking and requiring replacement. Other non engine issues were bad AC lines and the wonderful GM steering rack of the era. Just like my old Pinto wagon, had the Celebrity been just a bit less crude they really would have had a winner. I loved the size of that wagon.

I have an 80 CJ5 with this engine. It sure isn't over powered. Never have twisted the drive shaft into on it. Anyway it has always been dependable, expt the time a spark plug fould about 30 miles from home in the back woods. 4 cylinders are weak 3 barely pulls it. Never noticed this vibration you speak of. Mine seems to run smooth. Not nearly as smooth as a Honda tho. It does sound more like a 4 cylinder Farmall H tractor than an automobile engine. Sometimes I'd use it to pull plows. It does sound like the 134 CI. Farmall engine in our Super C Farmall tractor.

Had 2 celebrity's in high school and college. A 1984 and a 1989. Both cars had around 120,000 miles when I got them took them both past 200,000. I will say the 89 was much more refined than the 84 was.

Wait... My '89 S10 2.5L had a balance shaft? 😆 That entire truck was pretty smoked before I ended up with it so it wasn't a museum quality specimen, but "agricultural" is literally the word I've used to describe the engine. In an S10 with deep gears and an overdrive manual transmission it really wasn't offensive (though mine had hilarious amounts of valve train noise), but good grief would it be miserable in a typical GM car of the era with a 3 speed auto and 2.xx gears. I actually ended up gearing the truck to 3.08 (from the factory 4.10s) so I could cruise it down the interstate at 80 all day, and did. It was also on Z28 wheels so it had reasonably tall 15" tires. This was during the $4+ gas era of the mid-2000s and I had a long commute to work and they often used me as a parts runner mule (getting paid company mileage) since I had a beater pickup to use. I saved/made a lot of money with that truck. Some weeks my mileages checks were more than my pay and I had actually considered putting an auxiliary fuel tank in it because I was tired of stopping for gas so often. Finally it died from what I suspected was a wrist pin coming apart (almost certainly due to my neglect and abuse...it leaked oil and I let it get low a few times... plus tons of burnouts and such just for laughs). Still drove it another 100 miles home with it knocking like crazy. Still got it's standard 30-ish mpg even when it was coming apart. It went to the crusher at something like 215,000 miles. I'm reasonably sure it would have drove itself there. I've had 2 2200 powered S10s since it went away and the low end grunt of the 2.5 is immediately noticeable as missing. But, pretty much anything above idle the 2.2 is a much better driving experience. Both engines are hilariously under powered, but I don't think my 2.2 trucks would have pulled the 3.08 gears as well. So, for me, I don't think I'd put it on the worst engines list, but you didn't say anything I can disagree with either.

“Crude, rude, and noisy” is WAY to accurate

As a GM retiree it always surprised me that the company didn’t embrace overhead cam and alloy engine components much earlier than they did; in the UK we made the overhead cam slant four from 1967 to 1979 which was available from 1.6 up to 2.3litres but could be taken up to 2.6 litres; the engine was smooth running and a good all rounder and was successful in motorsport thanks in part to being very oversquare; Pontiac also made an overhead cam six for a few years too.