AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: Nightpath on April 11, 2014, 07:56:46 AM

Title: 4.0 head swap done right?
Post by: Nightpath on April 11, 2014, 07:56:46 AM
Howdy all,

I see about 50 threads all discussing the 4.0 head swap, but all have different information about it.

If one were to do the 4.0L head swap, what are the parts that are needed 100% to have it done right? What I mean is that some people just swap the head and mosey on with their day, but from what I gather the cam is a necessity to ensure you get the full bang for the buck, and changing the timing belt out at this time is a good idea. Some people mention lifters and other things.

So, if you had a moderate budget, what would be needed to get the most bang for the buck, keep in mind that you have to stay carb'd and have an HEI.

Edit : I also don't see anything like this in the How to or any other resources. Looks like it's a subject that comes up quite often.
Title: Re: 4.0 swap done right?
Post by: Mernsy on April 11, 2014, 11:25:48 AM
Try this section.

http://amceaglesden.com/guide/index.php?title=Eagle_Modifications
Title: Re: 4.0 swap done right?
Post by: Nightpath on April 11, 2014, 12:31:08 PM
I don't see anything like I'm asking, much less the head swap.
Title: Re: 4.0 swap done right?
Post by: Mernsy on April 11, 2014, 01:01:34 PM
You don't see the head swap using that link?

Try this...

http://amceaglesden.com/guide/index.php?title=Great_Tips_from_tougeagle
Title: Re: 4.0 swap done right?
Post by: Nightpath on April 11, 2014, 01:16:33 PM
Nothing was populating on the links, must be the work computer.
Title: Re: 4.0 swap done right?
Post by: vangremlin on April 11, 2014, 04:30:40 PM
I had the swap done about a year ago.  You can read many of the details in this thread:

http://forums.amceaglesden.com/index.php?topic=42319.0

There are many write ups on the web about this swap, mostly on jeeps.  I found this one to be pretty good, with lots of pictures

https://picasaweb.google.com/85YellowCJ7/40HeadSwap#

Important things to consider:

- Finding a 4.0 head that doesn't need to be freshened up is a big plus.  Costs start to add up pretty quickly if you have to have the head rebuilt.

- While doing the head swap alone may provide some benefits, most folks believe that swapping in a new cam is just as important.  I did the cam swap with mine and am very pleased with the results.  However, it adds another layer of complexity.

-  Exhaust manifold/pipe re-routing is tricky but can be done. 

I'm definitely pleased with the results of the swap.  However, by the time I was finished, it wasn't cheap, but then again, I had a shop do the work.  If I was to do this again, I would strongly consider a complete 4.0 engine swap.  Complete 4.0 engines with wiring harness and computers can be found around here on Craigslist for $600-900.  This kind of swap would fully comply with the emissions requirements in my area.  Just something to think about, I don't think the effort to do a complete engine swap is more than a cam and head swap.

Title: Re: 4.0 swap done right?
Post by: Nightpath on April 11, 2014, 08:36:15 PM
Was thinking about a 4.0 swap, but wouldn't that cause my HEI I just ordered to be a waste of money, or can I use it on the 4.0 as well?
Title: Re: 4.0 swap done right?
Post by: vangremlin on April 11, 2014, 09:10:48 PM
Quote from: Nightpath on April 11, 2014, 08:36:15 PM
Was thinking about a 4.0 swap, but wouldn't that cause my HEI I just ordered to be a waste of money, or can I use it on the 4.0 as well?

I'm pretty sure it will still work on a 4.0 engine, because I believe they still had a distributor not individual coils at each cylinder.
Title: Re: 4.0 swap done right?
Post by: eaglefreek on April 11, 2014, 09:19:59 PM
Quote from: Nightpath on April 11, 2014, 08:36:15 PM
Was thinking about a 4.0 swap, but wouldn't that cause my HEI I just ordered to be a waste of money, or can I use it on the 4.0 as well?
Only if you go with a carb. If you choose the Jeep MPFI you will need to use the Jeep distributor.
Title: Re: 4.0 swap done right?
Post by: vangremlin on April 11, 2014, 09:29:38 PM
Quote from: eaglefreek on April 11, 2014, 09:19:59 PM
Quote from: Nightpath on April 11, 2014, 08:36:15 PM
Was thinking about a 4.0 swap, but wouldn't that cause my HEI I just ordered to be a waste of money, or can I use it on the 4.0 as well?
Only if you go with a carb. If you choose the Jeep MPFI you will need to use the Jeep distributor.

Thanks for clarifying eaglefreek!
Title: Re: 4.0 swap done right?
Post by: eaglefreek on April 12, 2014, 05:40:59 AM
I should of said carb and some forms of efi depending on the system.
Title: Re: 4.0 swap done right?
Post by: mudkicker715 on April 12, 2014, 07:28:29 AM
The title of this thread is misleading. Or is it? what are you asking advice for? Your getting answers for a head and cam swap. So your asking for an entire motor swap? For the bang for the buck factor i just stroke the mofu. Problem solved.
Title: Re: 4.0 head swap done right?
Post by: Nightpath on April 14, 2014, 01:34:52 PM
Didn't realize that I left "head" out of the topic title.

Probably do a 4.0 swap from a 91-95, and use the crank and rods out of the 4.2 plus the water pump if needed. More HP = w00t