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 4.2 (Kept the T5 manual) :
I first had to locate a bell housing from a 6cyl CJ that would work with my T5. Luckily, being as the 4.2/T5 was an option, that wasn't difficult. The 2.5 and the 4.2 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 T5 to correspond with the 4.2 flywheel clutch assembly.

The 4.2 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" 4.2 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 4.2 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.