85 CJ7 4 cylinder

[fzsk4p]

Hi folks,
as my avatar mentions....Looking for a CJ to rebuild.........Found an 85 CJ7 on CL but it is a 4 cylinder.

Want to get educated before I make an offer/look on it.

Could be an AMC 4 or an Iron Duke. Not sure when the change over year(s) were.

Would the axles be the typical Dana 30 /AMC20 as found in a 6 cylinder ?

Transmission /Transfer Case ?

Likely swap in a 4.X but am wondering abut the rest of the drivetrain.

IE did Jeep use a specific 4 cylinder drivetrain that would require a different Transmission /Transfer Case for a 4.X swap ?

How about differences between the AMC 4 vs. the Iron Duke driveline ?

My searching thus far has raised more questions/confusion then answers.

A link would be fine.

Thanks !!

 

[elwood blues]

1985 was an AMC 150 , 2.5L 4 banger. Stock axles would be the wide track version of the Dana 30 /AMC20 , Transfer Case would be a Dana 300 .

Lot's of good info CJ (all years and makes) drivetrain here;

KEEP ON JEEPIN'

 

[CJim7]

Is it an auto or a manual?

This is what I had to do when I swapped out the 2.5 for a AMC 258 i6 / 4.2l (Kept the T-5 manual) :
I first had to locate a bell housing from a 6cyl CJ that would work with my T-5 . Luckily, being as the AMC 258 i6 / 4.2l /T-5 was an option, that wasn't difficult. The 2.5 and the AMC 258 i6 / 4.2l do not share the same engine bolt pattern, so this is required.

Next I had to swap out the 10 spline input shaft with a 14 spline on the T-5 to correspond with the AMC 258 i6 / 4.2l flywheel clutch assembly.

The AMC 258 i6 / 4.2l sits back further in the engine compartment then the 4cyl, so the whole drivetrain moves back about 2 inches. This requires shortening and lengthening the drivelines and moving the tranny crossmember back to the next set of holes in the frame.

You will need a 6 cylinder radiator, and if you use a "newer year" AMC 258 i6 / 4.2l with a clutchfan, you must use a radiator with the off-centered cap. The older CJ's used a radiator with a centered cap that was deeper and it will interfere with the fan. Be sure to use a shroud also.

You can re-use the stock ignition control module...not sure about ECM as I de-smogged mine prior to a swap and none of it was functional anymore.

4cyl equiped CJ's had 4.10 gearing from the factory...a definate plus.

 

[fzsk4p]

Is it an auto or a manual?

This is what I had to do when I swapped out the 2.5 for a AMC 258 i6 / 4.2l (Kept the T-5 manual) :
I first had to locate a bell housing from a 6cyl CJ that would work with my T-5 . Luckily, being as the AMC 258 i6 / 4.2l /T-5 was an option, that wasn't difficult. The 2.5 and the AMC 258 i6 / 4.2l do not share the same engine bolt pattern, so this is required.

Next I had to swap out the 10 spline input shaft with a 14 spline on the T-5 to correspond with the AMC 258 i6 / 4.2l flywheel clutch assembly.

The AMC 258 i6 / 4.2l sits back further in the engine compartment then the 4cyl, so the whole drivetrain moves back about 2 inches. This requires shortening and lengthening the drivelines and moving the tranny crossmember back to the next set of holes in the frame.

You will need a 6 cylinder radiator, and if you use a "newer year" AMC 258 i6 / 4.2l with a clutchfan, you must use a radiator with the off-centered cap. The older CJ's used a radiator with a centered cap that was deeper and it will interfere with the fan. Be sure to use a shroud also.

You can re-use the stock ignition control module...not sure about ECM as I de-smogged mine prior to a swap and none of it was functional anymore.

4cyl equiped CJ's had 4.10 gearing from the factory...a definate plus.

Thanks guys,
Good information provided.

Likely do simple OBD 1 EFI 4.X engine. Little bits of information like the radiator are priceless, thanks again.

Jim, you mention the AMC 258 i6 / 4.2l setting back a couple inches. No problem with that. But are the engine mounts (frame side) the same for a 4 vs a 6 ?

On a YJ the 4 cylinder mounts are different in design AND location then the 6. So I am curious about a CJ application.

The 4 cylinder is appealing if for no other reason the 4.10`s in the axles. Even more so now that I understand the Dana 300 TC is common between the 4 and 6.

A 4.X combined with a decent 4/5 speed. Running 33`s would be about right for what I want to do. `56`s would be better but could live with the `10`s.

 

[CJim7]

Thanks guys,
Good information provided.

Likely do simple OBD 1 EFI 4.X engine. Little bits of information like the radiator are priceless, thanks again.

Jim, you mention the AMC 258 i6 / 4.2l setting back a couple inches. No problem with that. But are the engine mounts (frame side) the same for a 4 vs a 6 ?

On a YJ the 4 cylinder mounts are different in design AND location then the 6. So I am curious about a CJ application.

The 4 cylinder is appealing if for no other reason the 4.10`s in the axles. Even more so now that I understand the Dana 300 TC is common between the 4 and 6.

A 4.X combined with a decent 4/5 speed. Running 33`s would be about right for what I want to do. `56`s would be better but could live with the `10`s.

Yes, the 4cyl frame brackets are different from the 6cyl brackets. I believe I have a set of 6cyl brackets out in my "spare parts". If and when you pull the trigger on a swap, and you need the mounts, just let me know.

AMC used a lot of the same parts between the 4 and 6cyl equiped Jeeps. The tranny's become an issue because of the spline difference with the input shaft, but for $125 you can swap that out if you are inclined to keep the T-4 /T-5 .

Are you considering swapping in a 4.0 or a FI AMC 258 i6 / 4.2l ?

 

[fzsk4p]

Jim,
thanks for the info/offer. Knowing what you and Elwood have provided in terms of information has opened a lot of doors.

Not afraid of tearing into a Transmission or TC. If nothing else, fresh seals, bearings, syncro`s and the like will provide familiarity and confidence.

Engine wise....Likely a 4.0 with an OBD 1 FI system will be good enough. Maybe another stroker (albeit a bit tamer) like in the YJ is a consideration. Have the harnesses and ECM to do it.

Although a AMC 258 i6 / 4.2l with a 4.0 head and OBD 1 is not out of the question.

Plenty of options. Will weigh it all out when the time comes.

The most important tool is the knowledge that the 4 and 6 cylinder CJ`s carry so many common parts.

You and Elwood have help immensely.

Some parts like radiators an expendable items

 

[CJim7]

Oh heck...I just remembered I have a radiator also. I bought it brand new several years ago when I swapped in my AMC 258 i6 / 4.2l and other then the usual bent fins, it's in perfect condition.

It's been boxed up and essentially ready to ship ever since I pulled it to install a bigger radiator for my 401 swap 4 years ago. I'll give you a really good deal on that also if/when the time comes.

 

[CJim7]

I really like the 4.0 headswap on a AMC 258 i6 / 4.2l . I was completely amazed when I did my conversion, at the amount of power and torque I gained.

I know a lot of people prefer the straight up 4.0 route, but you get stroker-like qualities using the AMC 258 i6 / 4.2l bottom end.

I would happily still be running my 4.0/AMC 258 i6 / 4.2l hybrid if the block hadn't given out on me

If I had another CJ to mess around with, I think I would build another hybrid. Really like the inline 6 and the diversity it offers.

 

[fzsk4p]

Let`s see how this goes.

Thanks Jim !!

 

[jeep whisperer]

i just went through the same engine swap. i had the same engine and drive line just like you. you almost need a parts jeep with a AMC 258 i6 / 4.2l to make what you want happen. i know for a fact the motor mounts, bell house, and input shaft are not compatible. the wire harness is shorter. after i put the AMC 258 i6 / 4.2l i used a T-4 tranny out of a AMC 258 i6 / 4.2l that engine then the AMC 258 i6 / 4.2l blew up. after pricing out how much it was to rebuild the AMC 258 i6 / 4.2l it was cheeper to make it fuel injected. then i put a 4.0l efi engine in the same jeep. and that was definitely the best way to go. at the end of my project i wish i had put it in right off the bat.