Engine 83 CJ-7 Will a 4.0 bolt in a 4.2

[Badmeester]

Hello everyone,

My name is John and i'm from Europe.(Netherlands)
I really like American cars/trucks and i'm currently owning a 94 Ram 2500 Cummins manual and a 06 Ram 2500 cummins as a daily.
Most of the maintainance and repairs are done by myself.
After a lot of discussion with my wife I've recently bought a 83 CJ7 with the AMC 258 i6 / 4.2l engine and 5 speed Transmission from one of my collegues.
According to my collegue it needed ''some'' work because the engine was leaking oil like crazy.
The price was about right so i've bought it.
So i've high pressure cleaned the block and changed the rear main seal, timingcase seal, oil pan gasket and fixed the valvecover.
After fixing this i went for a testdrive, this was the first good testdrive since i've owned it because of the major oil leaks.
After a few miles i've stopped and looked under the hood to see if if the engine was leaking again.
So far so good.
When i got home i've checked again and there was no oil leak luckily, unfortinately there was a crack(3 inches) in the block on the driverside a bit to the rear.

I've had bad experiences with JB Weld and welding a cast iron engine block so i'm looking for another engine.
Over here in Europe parts availability is a disaster for these old jeeps.
All the small stuff isn't a problem but engines, transmissions and axles are a drama.
At first i was looking for a AMC 258 i6 / 4.2l but i can't find one over here, only a reman for $6K which is even more then i paid for the jeep.
So i've found a 4.0 out of a 93 ZJ with 100K miles($1000), with both headers and all the belt driven components.
I've used the search function here but i think i can't find the right answer to my questions.

1.Will this engine bolt right into my CJ7 ?
2.Will the old intake manifold with carburettor from the AMC 258 i6 / 4.2l fit on the 4.0?
3.Will the old exhaust manifold fit to the 4.0?
4.Which ignition do i need, can i use the old one from the AMC 258 i6 / 4.2l ?
5.Do i need to change something else?


I hope you guys can help me,

John

 

[Manic Mechanic]

While yes it will bolt in most of your components won't work for. The exhaust is completely different and intake has to be modified. Power steering (assuming you have it) won't bolt up. You will have to run an electric fuel pump as there is no provision on the 4.0 block for a mechanical fuel pump. The harmonic balancer is another issue as well since the 4.0 is a serpentine belt setup and the AMC 258 i6 / 4.2l is a vbelt. I'm sure I'm missing a few things as well.

 

[yellow85cj]

The AMC 258 i6 / 4.2l intake will fit. Very minor work to make it line up with the 4.0 head. You will need the exhaust manifold from the 4.0. You can use the balancer if you use v belt alternator and power steering and water pump. The water pump should be for a AMC 258 i6 / 4.2l as the 4.0 water pump runs in reverse as it is for a serp belt. You can use the AMC 258 i6 / 4.2l flywheel and clutch, but have to use a AMC 258 i6 / 4.2l starter. As stated , electric fuel pump will be necessary . I have been using a 4.0 head on my AMC 258 i6 / 4.2l so I know the intake and exhaust will work together. I did have to mod the PS bracket to block slightly as the 4.0 is a little taller. You make have some difficulty finding a pilot bushing/bearing that will fit the 4.0 and the CJ Transmission . It is can be done. May have to find one that fits one or the other then do a little "machining". I'm starting the same thing you are asking about. Replacing the AMC 258 i6 / 4.2l with a 4.0 and keeping it carb'd.

 

[Manic Mechanic]

If it were mine I'd just go ahead and do the complete 4.0 with fuel injection. More power better fuel economy and cold starts

 

[Badmeester]

Thanks for the fast replys.
I forgot to mention that i run a propane system, kinda the same system as a forklift.
I will install an electric fuelpump for backup or when it´s too cold to start on propane.
The evaporatorsolenoid from the propane installation is already relay controlled so i can switch between gas and propane.
If fuel prices here weren't that crazy high($9,20/Gallon) i would stick with regular gas and convert to fuel injection.
When i convert to fuel injection i need to change the propane installation and the car has to be re-inspected which is going to cost me another $2K.

 

[Manic Mechanic]

That does change things up a bit. As long as you're going through all this hassle you can take the crank and rods from your AMC 258 i6 / 4.2l and put them into the 4.0 and build a stroker motor.

 

[Badmeester]

If i had the time, parts and a nice place to work i probably would go that route. Goal for now is to get the jeep runnin and driving as cheap as possible so we can enjoy it this summer. I'm doing all the work on my driveway and shed(10ftx18ft)
End of the year is my new shop(33ftx33ft) finished and i will take my projects to a higher level.

 

[Manic Mechanic]

Keep us posted.

As far as the garage whatever size you're thinking go bigger. Mine is 36x30 with 12' ceiling. Thought it was more than enough. Now I'm looking at additions.

 

[Badmeester]

Haha, the more space you have the more cars you buy. In the Netherlands land is very expensive. I would have go bigger if the costs for land and permits weren't so high.
I'll keep you guys posted.

 

[Manic Mechanic]

I know. I still have to many and want more. This was before I began thinning the heard

 

[Belizean]

Looks like a bunch of crawfish ponds behind the garage there.

 

[Manic Mechanic]

Coy ponds
My neighbor raises them. I've heard rumor he's the largest supplier in the US.

 

[Badmeester]

Wow, what a nice collection and what a great place.

 

[Belizean]

My brother has 3 small ponds in his backyard with Coy.

 

[Manic Mechanic]

My brother has 3 small ponds in his backyard with Coy.

Probably came from my backyard. He has around 200 acres with deeds dating back to 1865

 

[CJ]

4.0l vs AMC 258 i6 / 4.2l people ...