How to resurrect an old engine design no longer made?

AOSJ

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Was just reading about the engine options for the 2029 Wrangler that's coming out and it made me wonder:

"Why hasn't someone started producing a copy of the AMC 4.0?"

Maybe it's been done, I have no idea, but other than money, what would stop an aftermarket engine builder from essentially re-creating the 4.0? Patents have long run out. TJs, YJs, and XJs are still on the road and owners are enthusiasts, so they'd probably be a customer when their current engine gives up. Other platforms could use it, and it might sell well given it's reputation.

If mine ever gives up I would probably put a V8 in it, but the option of replacing it with essentially the same engine would be nice.

Edit: and I'm not asking why haven't the big car makers done this. I know the 4.0 doesn't meet greeny weeny EPA standards or whatever it is.
 
I don't think anyone needs to recreate it. You can easily buy a short block 4.0 and keep it running forever.

The hardest thing will be finding quality parts.

As for resurrecting it, nobody is going to do that because it wouldn't even come close to passing modern EPA regulations.

There isn't a single industry or institution that the government has gotten involved in that has been made better. The automotive industry (by way of the EPA and other regulatory institutions) isn't immune to that either. While the government isn't entirely to blame for cars being the way they are today, they play a very large part in it.

The good news is that you and I should presumably be able to keep these things running for the rest of our lives if we keep a stockpile of parts and maintain them.
 
As for resurrecting it, nobody is going to do that because it wouldn't even come close to passing modern EPA regulations.

Not to mention that engines really no longer drive the automotive market - at least in N. America. Nobody gives a damn about the engine, they just want to know how to connect their PHOOOOOONNE to the car. I'd like to see the GMC "Big Block" V6 resurrected, with modern upgrades such as head design and intake manifold design. That won't happen either, nobody cares about durability.
 
"Why hasn't someone started producing a copy of the AMC 4.0?"

Supply and demand. There is very currently very little demand for a Jeep 4.0 I6, and a relatively large supply of available 4.0s on the market.

Maybe it's been done, I have no idea, but other than money, what would stop an aftermarket engine builder from essentially re-creating the 4.0?

I highly doubt it will ever be done for the above reason. Look at the cost of a new SBC, an old engine that you can buy/build with all new parts that currently has lots of demand (relatively speaking) $10-20K. Now triple or quadruple that price for a ballpark range of producing a similar modern Jeep 4.0. I highly doubt any kind of market for $50,000+ 4.0s develops.
 
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Mazda I6 turbo is a great engine and other manufacturers should take a look at it. Very efficient, good power and has a good track record thus far.

Stellantis I6 Turbo Hurricane engine appears to be good thus far as well.

Why use archaiac design when newer more efficient I6 engines exist....hell I would take a Ford 300 I6 over a 4.0. Best I can see for 25+ years I have had one....they barely can pull themselves around. Sure they are great at not breaking....but what's the point if you can't motivate your own self?????
 
Supply and demand. There is very currently very little demand for a Jeep 4.0 I6, and a relatively large supply of available 4.0s on the market.



I highly doubt it will ever be done for the above reason. Look at the cost of a new SBC, an old engine that you can buy/build with all new parts that currently has lots of demand (relatively speaking) $10-20K. Now triple or quadruple that price for a ballpark range of producing a similar modern Jeep 4.0. I highly doubt any kind of market for $50,000+ 4.0s develops.

I never would've guessed it to cost that much! I watch too many motor trend shows where guys rebuild engines for a few thousand I guess!
 
15 MPG combined city/highway with very little HP or torque comes to mind. 🤫

I hear you but you're giving up some positives when you buy these small displacement, fuel efficient, turbo charged engines that are so ubiquitous now - I'm not that old and I hope I never have to buy a new car - I could have 40 more years of driving or more left
 
Underpowered = low stress = long life . This is why you can have a fully functional , gas farm tractor from the 1940's running today . It may have got a set of points with a cap and rotor in 1971 or 72 . :LOL: There is zero profit margin for recreating a low stress engine today , in my opinion .
 
Not to mention that engines really no longer drive the automotive market - at least in N. America. Nobody gives a damn about the engine, they just want to know how to connect their PHOOOOOONNE to the car. I'd like to see the GMC "Big Block" V6 resurrected, with modern upgrades such as head design and intake manifold design. That won't happen either, nobody cares about durability.

I sold my 3500 dually Ram Cummins truck with an 11' Lance fully featured truck camper on it, jake brake, individually adjustable air bags, etc. to a lady whose only question after a long explanation by me was " does it have blue tooth?"
 
I'd like to see the GMC "Big Block" V6 resurrected, with modern upgrades such as head design and intake manifold design. That won't happen either, nobody cares about durability.

What ?? with breathing capabilities like this ? It is hard for me to believe that you could build an exhaust valve that small , yet manage to fully shroud it in the combustion chamber .... :oops:

maxresdefault-2328089043.webp
 
I sold my 3500 dually Ram Cummins truck with an 11' Lance fully featured truck camper on it, jake brake, individually adjustable air bags, etc. to a lady whose only question after a long explanation by me was " does it have blue tooth?"

@Zorbas wife probably
 
Underpowered = low stress = long life . This is why you can have a fully functional , gas farm tractor from the 1940's running today . It may have got a set of points with a cap and rotor in 1971 or 72 . :LOL: There is zero profit margin for recreating a low stress engine today , in my opinion .

That's why Toyotas are so notorious for reliability. Tolerances aside, they purposely under-power them so they last longer.
 
FIFY .That ship has sailed a couple of decades ago.

Is that so? I hear that modern Toyotas are one of the only vehicles that still remain reliable and mostly trouble free. Of course I don't own one, that's just what I hear all the mechanics in those videos on X say.

We've got a 2005 Toyota RAV4 with 81k original miles. It's got the 2.4 engine from the Camry. Small vehicle but relatively simple, cheap, and I suspect it should last us for decades to come. I like older Toyotas.
 
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Is that so? I hear that modern Toyotas are one of the only vehicles that still remain reliable and mostly trouble free. Of course I don't own one, that's just what I hear all the mechanics in those videos on X say.

We've got a 2005 Toyota RAV4 with 81k original miles. It's got the 2.4 engine from the Camry. Small vehicle but relatively simple, cheap, and I suspect it should last us for decades to come. I like older Toyotas.

Ummmmm.....shhhhhh.....the twin turbo 4 cylinder is not doing so hot in the Tacoma, 4Runner and LandCruiser.

Single turbo V6 in the Tundra, GX and LX....they seem to be doing pretty good though.
 
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Ummmmm.....shhhhhh.....the twin turbo 4 cylinder is not doing so hot in the Tacoma, 4Runner and LandCruiser.

Despite how fun it is to drive a vehicle with forced induction, there's no getting around the fact that they require more maintenance (frequent oil changes and the right kind of oil) and most people don't know how to drive (or maintain) them. Nowadays everything has a turbo (which has allowed them to get rid of bigger engines in favor of smaller, forced induction engines) but that comes with a price. Reliability is certainly part of the price.

Older Toyotas do feel underpowered by today's standards, but there's something to be said about that as far as reliability and longevity goes.
 
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Is that so? I hear that modern Toyotas are one of the only vehicles that still remain reliable and mostly trouble free. Of course I don't own one, that's just what I hear all the mechanics in those videos on X say.

We've got a 2005 Toyota RAV4 with 81k original miles. It's got the 2.4 engine from the Camry. Small vehicle but relatively simple, cheap, and I suspect it should last us for decades to come. I like older Toyotas.

Read about the new Tacoma's and their turbo ed engines , it's kinda the same as everyone else's stuff now. Our Toyota's are a 98 4Runner and 04 Tacoma both with 3.4 v-6 230,000 and 260,000 respectively. They are relatively simple , trouble free , and yes 2 decades old . I suspect your 05 RAV4 would be in the same category .
 
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Read about the new Tacoma's and their turbo ed engines , it's kinda the same as everyone else's stuff now. Our Toyota's are a 98 4Runner and 04 Tacoma both with 3.4 v-6 230,000 and 260,000 respectively. They are relatively simple , trouble free , and yes 2 decades old . I suspect your 05 RAV4 would be in the same category .

Honestly, I didn't realize they had switched to turbo engines but I'm not surprised. Everyone would rag on the Tacoma for being underpowered compared to all the other half-ton trucks on the market. That's because Toyota was the only one using a naturally aspirated V6. Everyone else was already using a V6 twin turbo or a V8. Toyota isn't dumb, they did this for a reason.

The older Toyotas last the way they do because they're simple engines much like the legendary Honda K-series engines. The moment you turbocharge an engine you open up a whole different can of worms. I'm in the process of getting rid of my F150. It's an awesome truck to drive but I know it's going to turn into a maintenance nightmare in the long run and I am at the stage in my life where I want to buy vehicles that can last me for decades (ones that I can work on myself also).

I used to have a 04 Tacoma with the 3.4 V6. That thing had 300k miles on it with nothing other than basic maintenance. It wasn't much good at towing (very underpowered), but you could always count on it getting you where you needed to go.

My step-dad has a 02 Tundra with the V6 and a manual transmission. He's had it since it was brand new in 2002. Never once let him down and all he's done is basic maintenance.

Our constant thirst for power has lots of compromises.

The switch to smaller turbo engines has a lot to do with governmental regulations around fuel economy, emissions, etc.
 
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Despite how fun it is to drive a vehicle with forced induction, there's no getting around the fact that they require more maintenance (frequent oil changes and the right kind of oil) and most people don't know how to drive (or maintain) them. Nowadays everything has a turbo (which has allowed them to get rid of bigger engines in favor of smaller, forced induction engines) but that comes with a price. Reliability is certainly part of the price.

Older Toyotas do feel underpowered by today's standards, but there's something to be said about that as far as reliability and longevity goes.
I suppose that may be accurate for new versions, which I have no knowledge of. I daily drive a 20 year old turbocharged, intercooled, fuel injected 5 banger that puts out 300 horsepower. It gets regular 7500 mile synthetic oil changes. And that's about all the maintenance it has needed for the past 20 years with me beating on it.