Engine Swap

[nateppler10]

I need a new engine for my MJ. What's the best, cost-efficient option? Would I be able to use an engine from a Cherokee to fit my Comanche. Any information helps. I'm not very knowledgeable about cars/trucks, but willing to learn. 

[dasbulliwagen]

What happened to the old one. At 131,000 you shouldnt need to be replacing unless something catastrophic happened. The 2.5 is as good for high milage as the 4.0 is.

 

As long as all your accessories and manifolds are ok, I beleive you can get a 2.5 from any Cherokee, YJ or TJ Wrangler or Dakota, swap all your manifolds and accessories over to the new engine and bolt it back in. Youd also have to swap the flywheel if you get one from a 91 or newer model as the tone wheel on the flywheel is different than the earlier models. If Ive given any bad info, I'm sure someone here will correct me. 

[nateppler10]

On 6/11/2019 at 9:37 AM, dasbulliwagen said:

What happened to the old one. At 131,000 you shouldnt need to be replacing unless something catastrophic happened. The 2.5 is as good for high milage as the 4.0 is.

 

As long as all your accessories and manifolds are ok, I beleive you can get a 2.5 from any Cherokee, YJ or TJ Wrangler or Dakota, swap all your manifolds and accessories over to the new engine and bolt it back in. Youd also have to swap the flywheel if you get one from a 91 or newer model as the tone wheel on the flywheel is different than the earlier models. If Ive given any bad info, I'm sure someone here will correct me. 

The old engine has a cracked head gasket. And won't turn over at all. 

[Pete M]

won't turn over with the starter?  or won't turn over using a breaker bar? 

 

the 2.5L block went pretty much unchanged from 84-02 so any year can give you a new block  

[nateppler10]

It won't turn over with the starter. I changed the batteries and it attempted to do something whereas before, it wouldn't do a thing. 

 

[Pete M]

what noises is it making when you try?

[mjeff87]

It could be hydrolocked if the gasket leak is internal.  Pull the plugs, then try to spin the engine with a socket/breaker bar on the nut holding the harmonic balancer on.

 

I doubt you need a whole new engine, but it's too bad you're so far away.  I've got a perfectly good 87 2.5L sitting in a barn up in PA you could have for free.

[omega_rugal]

diagnose that engine first

[nateppler10]

Well, the last time I tried, it lunged forward and before I realized it could have been in gear I had already started the deconstruction. 

[Ωhm]

On 6/13/2019 at 1:38 AM, nateppler10 said:

The old engine has a cracked head gasket. And won't turn over at all. 

If it won't turn over it could have never lunged.

[Pete M]

just for clarification, "turn over" means that the starter is rotating the engine.   

[nateppler10]

Thanks for the clarification. Haha, I warned y'all. I have no idea what I am doing. Learning as I go. 

[thecodemonk]

Most cost-efficient for any engine swap is going with the same engine you already had in there.  

 

like the others said, finding the actual root cause is probably the cheapest and least effort route, followed by swapping in the same engine from another of the same vehicle.

 

A cracked head gasket isn't too bad...I'd want to know what else is going on though.  It's not too bad to take the head off if needed and take a look.