Iron Duke. How bad is it gonna hurt

racerfink said:

L5wolvesf said:

Back in the 80s the Duke was run in IMSA GT and ARCA cars so there has to be something to them. 

That was a totally different block called the Super Duty.  For a while, after IMSA GTU and the NASCAR Dash series went away, you could buy complete, 300hp Super Duty's for less than $2,000 all day long.

I ran an Iron Duke in my SCCA ITB Fiero.  There are some incredibly rare Holley pieces, an intake manifold and a TBI, that increase hp about 35-40 percent.  The other thing to do is port the head, and especially take out all the flashing left behind from a very old casting.

I wastched some S-10's at Langley Speedway absolutely dominate a 4cyl truck race, so there is potential there, but good luck finding all the 40 year old pieces needed to make it happen now.  If it were me, I'd drop in a 2.0L turbo Ecotec motor, have almost 300hp, and get almost 30mpg around town, and well into the 40's on the highway.

Do you have a picture your SCCA Fiero?

Perpetual motion engine if  I recall. At that point you have no need for acceleration.

If just hauling your bulk or a wheelbarrow worth of load in back, it will do that task quite well until both you and the engine die of boredom.

The mercruiser engines aren't based on the Pontiac engine they are based on the chevy 2 engine.

Put a lot of nitrous on one. Couldn't kill it. 

I put a crazy amount of very hard miles on two of those S10's. And I'd buy another one in a second. Nothing wrong with the Duke. 

barefootcyborg5000 said:

In reply to Curtis73 (Forum Supporter) :

This would be the "low" tech IV. 
TBI for the win? The system doesnt scare me at all, and confident I can keep it going and repair whatever may fail. 
Maybe I get lucky and find another NOS torsen diff for cheap. 

When I was 18, I had an absolute base model '85 with the duke. The truck had a factory 4.11 rear end, and a 4 speed, and mechanically it couldn't go more than 85 MPH, but it was surprisingly quick up to it's mechanical limit.

I loved that truck. If I found a clean 5 speed version for sale tomorrow for the right price, I'd snap it up.

the 2.5 will run as long it has oil and gas.  The valve covers leak like mad, but once you handle that its an easy truck to maintain. Not much power to play with, but it will get you there.  When engine swap day comes I'd be tempted by a 3.8 V6 from a 98-2002 Camaro/Firebird. 200hp, fairly light and 30mpg freeway isn't out of the question.

Well, it's a done deal. I looked it over top and bottom. Little test drive. It runs as good as a Duke can. Factory AC that someone removed. 5 speed, MANUAL STEERING! No rust to speak of. 
Spare hanger is snapped, so it's in the bed. Noticeable dent in the gate, a bit stiff to open but it works. Second and 4th have no more synchros. Double clutches just fine. 
Parked with family in that town until I can drive it home during daylight.
Headlights were installed by this guy:

He's an shiny happy person. 
Major shiny happy person. 
 

So that happened. 
 

In reply to SKJSS (formerly Klayfish) :

Don't have any of it on track, but here it is the day I drove it home.

In my dad's garage being built.

Completed and ready to go to a track day at Sebring.

Sitting under the old pit boxes at Sebring.

That's the only engine GM ever built that never needs to be rebuilt. 

By the time it's worn out, you can replace whatever vehicle it's in for less than the rebuild cost.

1993 181k clean title. In this market, I'll take the price. I could reasonably slap a turbo and still make challenge. Probably still slower than my mustang. 
Plans: 

Short term- Deferred maintenance. Fluids. General cleaning. Truck stuff. Hauling couches and bikes. Proper hitch install.

Longer term- UCAs, tall ball joints, blazer bars, drop spindles and springs. Aiming for 5" total. I think I like these wheels. Interior refresh (reupholster seat, cover dash, carpet, funky headliner, replace horn button) 

Possible eventualities- boosty 4 swap, LSD, party?

Why the Iron Duke sucks, and other interesting trivia:  Worst GM Engines of All Time series

In reply to barefootcyborg5000 :

Looks like a great buy.

Stampie said:

In reply to barefootcyborg5000 :

Looks like a great buy.

agreed. Always had a soft spot for square s-dimes

I had an 87 5 spd that was a bit of a beater, but my first one was an 86 base model contractors special. 4 speed trans, 3.42 gear and no options. It developed a wrist pin knock that was so loud at idle people thought it was a diesel, and when something went wrong with the clutch at about 350k I swapped in a low mileage 87 motor with 5 spd trans. Rust got to it, but I gave it to a kid in the village and he managed to get a few more years out of it.

I loved that truck, and have considered looking for one to import from the southern US.

oh man, we've got the faster younger brother of that. 99 base single cab long bed but with the v6. It's the perfect little truck for 99% of anything I'd ever need a truck for. Great find!

In reply to racerfink :

Now that you mention it I do sort of recall the Super Duty thing.

A guy here has had an ex huffaker imsa fiero. He originally raced up here with the super dusty later with an asa stock car v6 then a Chevy v6 turbo. He also raced a super duty 4 in a Datsun 510 ice race car at one point.

Streetwiseguy said:

If I had to choose between an Iron Duke and a 60 degree V6, I'd go iron duke all day long, and twice on Sunday.  At least you don't expect much out of half a 302, whereas the idea of a V6 is appealing, until you try to stuff the truck in 5th gear, and it slows down.

I hate GM 60 degree V6 engines.  I merely dislike iron dukes.

Surprised at that.  The Iron Puke (so called because of what they usually did when you try to force them to put out much power) was a boring but useful engine in original form, but not a performance motor unless you tossed out everything including block, head and bottom end and went with a Super Duty engine.

While the earliest 2.8 V6s had some weaknesses, that was fixed early on and the later versions were reliable. I built a turbo 300 bhp motor that ran reliably at 10psi of boost for almost 20 years - couldn't ask for more than that. I also chose the 3.4 version (200 bhp) to power a transplanted MG and it does a great job.  Did you have one blow on you to sour you on the design?

That looks like a great, rust free truck that's going to be reliable. I don't think you made a mistake, Iron Duke or not.

Had a poontiac grandammit that had the "tech IV", an uninspired lump that did its job without a hiccup long past the time the entire rest of the car should have been relegated to the junkyard  for rust issues. (there was a softball sized hole in the drivers door...)

In the FWD configuration replacing the ignition coil in a driveway kind of sucked, but in a RWD configuration it should be easy peasy. (note, ignition coil only replaced after 24 years of service life)  Aside from that, I dont think we ever did anything regarding that engine aside from fluid changes. 

Looks like you have found a fine example of an automotice cockroach. Its a grand thing and as long as you dont ask it to be more than it is, it will bring your grandchildren happiness with proper attention.

IIRC, that thing shares parts with the Grumman LLV mail truck. With minimal attention, it will go over a million miles.