Best year for MJ build?

[lugnutz]

Looking for a lil help from the experts. I am looking for an MJ and I'm curious if there is one year better than the other for the base of a build project?

 

Case in point, I read a thread where a 4.0 was being swapped in place of a 2.5 and there was a firewall clearance issue.

 

I plan to do the newer Cherokee grille and dash conversion and have found an 86 model with a 2.5 but wonder if I should look for a newer year with a 4.0 to simplify things or are they pretty much all the same?

[yellaheep]

Yeah, I'm not a fan of anything earlier than '87.  If you're gonna do all that swapping, then '87 - '92 will all work the same.  If you're wanting to leave the drivetrain in place, but just want to swap over the late model stuff for looks, then '91-'92 are the best with the H.O. and OBD1.   But yeah, those are the hardest to find and generally fetch bigger prices.

 

'89-'92 got the AX-15 5 speed, an upgrade from the earlier BA10 Peugeot trans.

 

If you hadn't figured it out, the '86 was only available in long bed so if you're wanting a short bed, '86 won't get ya there.  And you're correct, the firewall and radiator support areas on the '86's are different and make fitting a 4.0 swap a challenge.

 

Other than that, not much else differed between '87-'92

[gogmorgo]

I understand the last few batches of '86 MJ's came with the later firewall, and the 86's did have some unique and therefor rarer options. But fewer people will cry if you chop an '86 to bits than any other year, it seems. People may hate you for tearing apart a 91+, though...

[lugnutz]

Yeah, I'm not a fan of anything earlier than '87.  If you're gonna do all that swapping, then '87 - '92 will all work the same.  If you're wanting to leave the drivetrain in place, but just want to swap over the late model stuff for looks, then '91-'92 are the best with the H.O. and OBD1.   But yeah, those are the hardest to find and generally fetch bigger prices.

 

'89-'92 got the AX-15 5 speed, an upgrade from the earlier BA10 Peugeot trans.

 

If you hadn't figured it out, the '86 was only available in long bed so if you're wanting a short bed, '86 won't get ya there.  And you're correct, the firewall and radiator support areas on the '86's are different and make fitting a 4.0 swap a challenge.

 

Other than that, not much else differed between '87-'92

 

The one I am looking at, the guy claims it's an 86 (2wd) and it does have the short bed. Could be a late year model though. I have access to a 2000 XJ and planned to use all the drivetrain, front sheet metal and do the dash conversion to it as well. 

 

Not looking to make a crawler out of it. I have a set of Rubicon wheels that I want to use with a little lift. Just looking to build an updated basic street truck that I can take Hunting and share it with the girlfriend. She really likes the Comanches.  :thumbsup:

[benjy_26]

 

 

Yeah, I'm not a fan of anything earlier than '87. If you're gonna do all that swapping, then '87 - '92 will all work the same. If you're wanting to leave the drivetrain in place, but just want to swap over the late model stuff for looks, then '91-'92 are the best with the H.O. and OBD1. But yeah, those are the hardest to find and generally fetch bigger prices.

 

'89-'92 got the AX-15 5 speed, an upgrade from the earlier BA10 Peugeot trans.

 

If you hadn't figured it out, the '86 was only available in long bed so if you're wanting a short bed, '86 won't get ya there. And you're correct, the firewall and radiator support areas on the '86's are different and make fitting a 4.0 swap a challenge.

 

Other than that, not much else differed between '87-'92

The one I am looking at, the guy claims it's an 86 (2wd) and it does have the short bed. Could be a late year model though. I have access to a 2000 XJ and planned to use all the drivetrain, front sheet metal and do the dash conversion to it as well.

 

Not looking to make a crawler out of it. I have a set of Rubicon wheels that I want to use with a little lift. Just looking to build an updated basic street truck that I can take Hunting and share it with the girlfriend. She really likes the Comanches. :thumbsup:

If yoi plan on doing a full conversion, get anything made from 87 on up as long as it isn't too rusted.

[87MJTIM]

The 86 was only offered with a long bed.  The engine options were 2.5, 4 cyl, TBI, 2.8 GM V6, carb'd or 2.1 (?) diesel.  The firewalls will not fit the longer 4.0 engines without some re-shaping.  (It is rummered that later production models came with firewall shaped to fit the 4.0 engines.)

 

The 87 - 90 came with the 2.5, 2.1 and the 4.0 as options.  87 was the first year of the short bed, and was offered through 92.  These year are referred as Renix Jeep because of the engines used.  The 4.0 was fuel injected while the 2.5 was still TBI.

 

The 91 - 92 are the HO years.  This is when Chrysler put its stamp on Jeep (before they stamped out the MJ).  The 4.0 saw an increase in horse power and the 2.5 was FI.

 

Here's a link to more info on the MJ:

 

http://www.comanchemj.1hwy.com/photo6.html

[shelbyluvv]

The 86 was only offered with a long bed.  The engine options were 2.5, 4 cyl, TBI, 2.8 GM V6, carb'd or 2.1 (?) diesel.  The firewalls will not fit the longer 4.0 engines without some re-shaping.  (It is rummered that later production models came with firewall shaped to fit the 4.0 engines.)

 

The 87 - 90 came with the 2.5, 2.1 and the 4.0 as options.  87 was the first year of the short bed, and was offered through 92.  These year are referred as Renix Jeep because of the engines used.  The 4.0 was fuel injected while the 2.5 was still TBI.

 

The 91 - 92 are the HO years.  This is when Chrysler put its stamp on Jeep (before they stamped out the MJ).  The 4.0 saw an increase in horse power and the 2.5 was FI.

 

Here's a link to more info on the MJ:

 

http://www.comanchemj.1hwy.com/photo6.html

 

Close...

 

The 4.0 will fit in a 86 with minor mods to the firewall and core support. It takes a couple bumps with a hammer to clear the valve cover. The "RENIX Jeep" was not because of the engine. It is because of the Renault/Bendix fuel injection system. The "HO Years" are because the fuel injection system went to OBD-I.

[87MJTIM]

 

Close...

 

The 4.0 will fit in a 86 with minor mods to the firewall and core support. It takes a couple bumps with a hammer to clear the valve cover. The "RENIX Jeep" was not because of the engine. It is because of the Renault/Bendix fuel injection system. The "HO Years" are because the fuel injection system went to OBD-I.

 

 

Correct.

 

I wanted to point out some of the diff between years.  

[Megadan]

So much hate on the Renix years.  I don't get why  :hmm:

[lugnutz]

Thanks for the great info guys. The 86 I was looking at turned out to be a long bed. I will let you know what I come up with.

[shelbyluvv]

Thanks for the great info guys. The 86 I was looking at turned out to be a long bed. I will let you know what I come up with.

ALL 86S ARE LONG BEDS

[mikekaz1]

the best year is up to who your talking to...

 

in stock form the 91-92 are generally the best a little more engine output, more common 23 spline drivetrain, there the newest you can find (owners can destroy anything so this is negligible), they use OBD1 (hit or miss), the chryco electronics are a little more refined, ect...

 

87-90 use the renix electronic system (this can go either way good or bad), if your ontop of things it can work great and they can be a little more versatile on modifications.  these ttend to be a little more optioned for one reason or another, ect...

 

86.... eh  not awful but not anywhere as good as the rest, first model years are never that wonderful

[87MJTIM]

So much hate on the Renix years.  I don't get why  :hmm:

 

Mine is a Renix and I love it.

[SVPete]

Obviously I am partial to 1988, since it has lasted with my abuse for 28 years.....so far.

[64 Cheyenne]

Your plan is doing a 2nd gen swap? So why all the questions? Your talkin a MAJOR swap, dash, harness, engine controls, drivetrain, everything you will be using will come from the 2nd gen. Because of the magnitude of this swap, I really doubt firewall clearance and core support are big issues, imo these are small issues and you have many other hurdles to clear like dash support modifications that will make swinging a hammer for fire wall mods seem like small beans. And as far as years, it really don't matter, 86 gets you long bed and 2.8 or 4cyl and some structural mods , beyond that everything your talkin about doing will be done to any 2nd gen swap. If you have a complete donor, you have all you need for firewall and core support mods minus a BFH if you go that route.

[DirtyComanche]

Not all 89s have the AX-15.  It's a mid year change.  So don't think you're safe from the Peugeot just by buying an 89.

[Knucklehead97]

Personally my favorite year model is '90 due to it being the only complete year that had an AX-15 and Renix in it. If I could redo my purchase I would have held out till I found a good '90.