Engine swap. GM 2.5 to AMC 4.2

[DJ1980CJ5]

Hello All,

Still going through the trials and tribulations of my 1980 CJ5 . Four cylinder.

I'm at the point where I need to replace the "Iron Duke". At least a long block. Long story.

I am contemplating going to a AMC 258 i6 / 4.2l six. Howevrer, I don't know what the differences are regarding Transmission mounting, etc.

My Transmission . is a four speed (Ford Built).

IS that swap even worthwhile?

With as many of the 2.5's that ZGM bui;lt, you would think would be easy to find, THey're not.

Thanks.

 

[mtnwhlr]

If I was going to do a engine swap I would go with the 4.0 out of a mid 90s cherokees or Wrangler so you have factory fuel injection. I think the 4.0 high output is a great engine. People are swapping the 4.0 head on to the AMC 258 i6 / 4.2l I say put the whole engine in with the fuel injuction and say goodby to carb problems. IMO

 

[CJim7]

The AMC 258 i6 / 4.2l will not bolt up to the existing bell housing. I believe you have an SR4 tranny and the bell housing bolt pattern is Chevy. a Chevy V6 is an optional swap in this instance....other then that, swapping out the entire drivetrain for an AMC I6 along with its tranny and xfercase is your viable choice.

 

[DJ1980CJ5]

THanks All. That's kind of what I figured.

I'm not sure if it is worth all of that since the Transmission and Transfer Case are in perfect condition.

 

[cass]

you can get a I6 bellhousing to make the swap. they put the T-4 behind the 6 and you just need one of those factory bell housings. the T-4 and SR4 are directly interchangeable. ( i put a T-4 in my 80 CJ5 and it was a direct swap)

the T-4 i bought off craigslist came out of a 86 CJ7 with a I6.

 

[DJ1980CJ5]

you can get a I6 bellhousing to make the swap. they put the T-4 behind the 6 and you just need one of those factory bell housings. the T-4 and SR4 are directly interchangeable. ( i put a T-4 in my 80 CJ5 and it was a direct swap)

the T-4 i bought off craigslist came out of a 86 CJ7 with a I6.

Thanks. That's great information.

Is it also safe to say that a 4.0 will bolt up with the bell housing swap????

This GM 2.5 is driving me nuts.

I'm looking, now, at getting a reman. 2.5L but not sure it's worth it. I can't even find a lower thermostat housing for it. What a rare duck!

 

[cass]

i just swapped to a 350 chevy and i sold my 2.5 on craigslist. the lower thermostat housing was messed up onn it to. silicone was keeping it together. for what you would spend on that reman motor you might as well go with somthing with more power. those 4.0 motors are everywhere and they run awesome! the fuel injection wouldnt be to bad because a lot of guys have done it. that and i had my 2.5 on the trails alot and i wished like hell it was injected because going up hills it flooded out all the time.

 

[DJ1980CJ5]

i just swapped to a 350 chevy and i sold my 2.5 on craigslist. the lower thermostat housing was messed up onn it to. silicone was keeping it together. for what you would spend on that reman motor you might as well go with somthing with more power. those 4.0 motors are everywhere and they run awesome! the fuel injection wouldnt be to bad because a lot of guys have done it. that and i had my 2.5 on the trails alot and i wished like hell it was injected because going up hills it flooded out all the time.

Yah, my lower housing looks like swiss cheese after I removed most of the JB Weld. What a mess.

I think the 4.0 swap probably makes the most sense. I have to deal with emissions testing here so i don't know how a swap would be viewed by the DMV. Although, I'm sure an injected 4.0 would be much cleaner than a carb'd 2.5.

This is kind of too bad. I just got this 2.5 to pass emissions with a new Weber carb and a mild rebuild. Right after that, it spun a bearing, took the crank with it. I'm not sure it's worth rebuilding-again,

 

[DJ1980CJ5]

Another question.

I found an AMC four cylinder (2.5) on ebay. The seller states it came out of a CJ7 .

The bell housing (engine block pattern) looks like small block chevy. Or, what I have now.

Could that be true?

Thanks All.

 

[cass]

its probably the same one you already have. unless it was behind the amc 2.5L that was 82 to 84

 

[DJ1980CJ5]

its probably the same one you already have. unless it was behind the amc 2.5L that was 82 to 84

THe one I found is an AMC 2.5, not the GM "iron duke".

 

[cass]

im not sure if thats the same bolt pattern as the AMC 258 i6 / 4.2l or not. maybe somone will chime in