So I spun a rod bearing... now what?

[Philistine]

A friend stopped by today and took a listen to my engine noise and suggested it might be a bad rod bearing. After a bit of research I'm 95% certain (still have to pull the oil pan) I did spin a rod bearing. So now what?

 

It is repairable, but looks likely to be costly. I'm entertaining the idea of an engine swap, I don't feel like dumping a lot of money into a 24 year old 4 cylinder engine, but how much more would it cost to say swap in a rebuilt 4.0L HO? Mind you that I have an '86 Comanche and a 6 cylinder engine was not an option for that year so there are some clearance issues with the firewall. Also its not something I can do myself as I have just the basic tools and a small 1 car garage (the HOA wouldn't look kindly on me doing an engine swap in the street).

 

This isn't something that'll likely be happening right away so I want to figure out how much I'll have to save up to either fix the existing engine or swap in a rebuilt engine.

[Pete M]

as far as I've been told, any AMC 2.5 block from any Jeep 84-2002 (or whenever they switched to the 2.4 v4) can be a donor with minimal work. :thumbsup:

[Automan2164]

Yep, with basic hand tools, you would be fighting one hell of a battle with an HO swap. In order to put in anything besides another 2.5L you are talking major mods... Wiring harness, interior and engine bay, transmission, etc, etc... I would just keep the CL eyes peeled for a longblock, or if you plan on keeping the truck, why not just get a reman/new?

 

Rob L.

[Philistine]

if you plan on keeping the truck, why not just get a reman/new?

 

Rob L.

 

I definitely plan on keeping the truck. Its in great shape for its age (other than the engine). That's one of the options I'm considering. I don't want to dump money into fixing a 24 year old engine if it isn't prohibitively expensive to swap in a new or rebuilt engine.

 

I'm just trying to find out what my options are and what the costs could be.

[jimoshel]

You ain't gonna know squat until oyu drop the pan. I have had spun rod bearings where I was able to just replace the bearing with no more parts, work needed, and I have had some where I had to junk the crank. And the ones in between where the journal needed turned. Drop the pan and see what ya got.

[Eagle]

if you plan on keeping the truck, why not just get a reman/new?

 

Rob L.

 

I definitely plan on keeping the truck. Its in great shape for its age (other than the engine). That's one of the options I'm considering. I don't want to dump money into fixing a 24 year old engine if it isn't prohibitively expensive to swap in a new or rebuilt engine.

 

I'm just trying to find out what my options are and what the costs could be.

The trouble is that it IS prohibitively expensive to swap in a 4.0L if you are not set up to do it yourself. You basically have to gut the truck and replace everything. It isn't just the engine. The 4.0L will immediately require a different transmission and transfer case. You'll need a different radiator, and the radiator supports have to be ripped out and replaced to accept the 4.0L radiator.

 

Hammering the firewall is the least of the issues. To use a 4.0L, you will have to rip out the entire engine room wiring harness and replace it with the correct one for the engine you'll be installing. Easiest would be a Renix 4.0L, but even then the donor harness will probably come from a Cherokee and that harness won't mate up to a Comanche body harness without some customization. And the newest Renix 4.0L will be a 1990, so that's 20+ years old already. For the work involved, it would make more sense to swap in an HO, but then you have even more wiring issues to deal with.

[DJM/78]

I agree , after looking at swapping my 2.5 in the 91" , I found it to be the same amount of work and money to swap in a TBI V8 . I'm working on that now .

[dasbulliwagen]

The previous owner of my truck had Jasper put in a new engine for him.... that was 200,000 miles ago and shes still runnin strong. Just call around to local shops and get some prices, or go to Jasper website and see who is reccomended by them in your area. As far as a rebuilt longblock cost I think Jasper is pretty much right in line with everybody else. That will at least give you an idea what youll need to save. If you don't mind the 2.5 power, then just seak out anther 2.5. Thats the simplest solution.

[Philistine]

So I'm looking at just finding the same engine to swap in. It looks to be the easiest and least expensive route to get the MJ up and running again. Luckily I'm only a couple hours away from JW Auto Wreckers. Anyone have any specifics on what years the 2.5L used in my '86 was available till?

[Pete M]

2003 if you just need a new block.

[Philistine]

Thanks Pete. I'll see what they have.

[AMC-MJ]

I was told the AMC 2.5L TBI 86'-90' and the 2.5L MPI was 91'-93' then they went to the Chrysler 2.5L 94'+ due to high cost of manufacturing the AMC-2.5.

 

Look for an MJ/XJ or Cherokee / Comanche 2.5L 86'-90' would be ideal.

 

the 86' 2.5L TBI = 117hp & 135tq but the 87'-90' 2.5L TBI = 121hp & 140tq, not sure if its the engine itself that makes the extra power or the Computer system ? it could be interchangeable . . .

 

Now if you wanted to do the extra work the AMC-2.5L MPI makes 130hp & 150tq and might get better MPG's ?

 

Mike

[Philistine]

I was told the AMC 2.5L TBI 86'-90' and the 2.5L MPI was 91'-93' then they went to the Chrysler 2.5L 94'+ due to high cost of manufacturing the AMC-2.5.

 

Look for an MJ/XJ or Cherokee / Comanche 2.5L 86'-90' would be ideal.

 

the 86' 2.5L TBI = 117hp & 135tq but the 87'-90' 2.5L TBI = 121hp & 140tq, not sure if its the engine itself that makes the extra power or the Computer system ? it could be interchangeable . . .

 

Good info! Thanks.

 

Now if you wanted to do the extra work the AMC-2.5L MPI makes 130hp & 150tq and might get better MPG's ?

 

Mike

 

How much extra work would that be?

[AMC-MJ]

I would imagine you would have to transplant the engine harness and computer from the donor Vehicle as well as the engine I don't know the details of it but it might be easier then a 2.5 to 4.0 swap ? . . .

 

I was told to do the AMC 4.0L I-6 swap, but when i saw the work needing to be done i chose to swap in an AMC-V8 instead

 

 

Mike

[Pete M]

what's a "chrysler" 2.5?

 

car-part.com lists 91-01 blocks as the same part number.

 

AMC, are you thinking of the ignition system?

[AMC-MJ]

Chrysler 2.5L:

http://wapedia.mobi/en/Chrysler_K_engine#2.5

 

Chrysler engines

 

* 1967-1986 Simca Type 315 - Developed by Simca before its takeover by Chrysler and later manufactured by Peugeot, this engine family was famously used in the Horizon.

* Chrysler 2.2 / 2.5 engine - Chrysler developed a specialized straight-4 SOHC engine for the K and L platforms, and it was later used in their minivans as well as the P platform. The 2.2 L engine was eventually expanded to 2.5 L in 1985, and fuel injection and turbocharging were added. The highest-performance version of this engine was available with a 16V Lotus head, twin cams, a Garrett turbocharger with intercooler, and DIS. This version was rated 224 hp (167 kW).

* Chrysler Neon engine - In 1994, Chrysler modified the 2.2 L Chrysler K engine substantially for a 2.0 L straight-4 for the new Dodge Neon compact car. This same engine was and available in SOHC and DOHC variants, and the DOHC version was later expanded to 2.4 L for use in the Cirrus/Stratus/Breeze and was also later used in a number of Chrysler small cars and minivans, and even briefly in the Jeep Liberty. Turbocharged variants made their way into the PT Cruiser and the Dodge SRT-4.

* Tritec engine - Chrysler and BMW teamed up to build a 1.6 L version of the SOHC Neon engine (many similarities, reduced bore size and spacing, designed by Chrysler) for subcompact cars to be built in Brazil. Although this engine is not sold in North America in any Chrysler vehicle, it is available in the BMW MINI Cooper, and is used in international Neons and Chrysler PT Cruisers.

* Global Engine Manufacturing Alliance - Hyundai, Mitsubishi, and Chrysler worked together on a joint-venture 4-cylinder engine in 1.8, 2.0, and 2.4 L sizes.

 

http://wikicars.org/en/Chrysler_LeBaron_Coupe

 

Mike

[shelbyluvv]

Me being a Turbo Mopar nut I can weigh in on this a little.

 

The Mopar 2.2/2.5 never found it's way into a Jeep. Not even the common block version of it. If it would have you could place money that I would have a turbo MJ flying around. The 2.5 used in the Jeep is a totally different block and bell housing.

 

I have been playing with the 2.2 and 2.5 powered Mopars for over 20 years. I still to this day own a Garnet and Silver 87 Shelby Charger. This is where my user name is derived from.

 

So, to answer the question, yes Chryco and AMC made 2.5 liter 4s. They are nothing alike externally or internally.

[Pete M]

The AMC 2.5L was in Cherokees for their entire run and Wranglers until around 03 and was used in Dakotas for a while too.

I promise. :thumbsup:

 

http://en.wikipedia.org/wiki/AMC_Straight-4_engine

[AMC-MJ]

:yes: I know they are nothing a like the AMC-2.5 is much better then the Cryco-2.5 :thumbsup:

They replaced the Cryco-2.5 in the Dakota's with the AMC-2.5 cause it made more power :D

 

Yup Petes right:

The American Motors Corporation straight-4 engine was used by a number of AMC, Jeep, and Dodge vehicles from 1984-2002.

 

So was I it was better:

While clearly superior in power to the Plymouth-Dodge 2.5 liter engine, which produced at most 100 hp and 135 lb-ft of torque

 

AMC-2.5L = 102hp 84'-86' 1bbl Carb, 86' TBI 117hp & 135tq, 87'-90' TBI 121hp & 140tq, 91'+ MPI 130hp & 150tq, According my old jeep manuals under general data except the wrangler received a detuned version . . . why did they do that ?

 

Mike

[Pete M]

I bet the wrangler had a more restricted intake. I've heard that about the 4.0 in them so it stands to reason the 2.5 had a similar intake. dunno for sure. :dunno:

[Incommando]

The Wrangler eventually got the 2.4L Chrysler I4... But I am fairly sure that it was after the XJ run. The KJ got the 2.4.

[Philistine]

OK now were getting into information overload. I just want to replace my 1986 2.5L with an engine that I can basically overhaul and bolt in.

 

This is my winter project, but I'd like to get the right engine at the start.

[gl1200aman]

If you don't want a bunch of modifications on mounts and wiring the easiest is to replace it with what it already has. You can pull yours and have it redone, buy another at a salvage yard, or buy one already rebuilt. It all depends on your skills, availability of replacement, machine shops available. As stated above, you won't know how bad yours is until you see what it looks like inside. It depends on how long it has been run like that. If it spun the bearing and you stop running it the damage may be minimal but if you kept driving it a while it will have more damage.

 

A few years back I had an 88 with the 4.0 I6 and a place in Milw. wanted $2100 to pull mine a install a fresh rebuild with a 1 year warranty or I could buy it for $1800 and install it myself but no warranty. I found one for $200 at a salvage yard that was rebuilt and swapped it myself.

[Pete M]

86-90 all share the same block part number.

 

failing finding one of those in good shape, 91-00 share the same block part number and will go in with minimal hassle.

[AMC-MJ]

OK now were getting into information overload. I just want to replace my 1986 2.5L with an engine that I can basically overhaul and bolt in.

 

This is my winter project, but I'd like to get the right engine at the start.

 

Sorry for all the info i was just giving you some options that will bolt right in, and few that would also bolt in but need a few minor things done to work . . . I was just trying to help, but i see i caused a major :hijack: situation my apologies :bowdown:

 

 

Mike