AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: kajsdf on December 14, 2011, 12:39:12 AM

Title: several 4.0 head swap questions
Post by: kajsdf on December 14, 2011, 12:39:12 AM
i've been seeing a few 4.0 head swap kits on the 'bay lately -- anyone have any experience with these (if you can't find what i'm talking about by searching pm me for a link)?  if they are as good as they look, is the price pretty comparable to pulling one off an existing engine, cleaning/re-boring if necessary and getting all the other bits and pieces?

i am also curious what parts are necessary -- i know there are a million write-ups, but many of them are different.  i don't want any extra computer stuff if i can help it.  i know the mc21xx upgrade is necessary, and i plan to do that pretty soon anyway. 

i guess what i am trying to do is get a good idea of what exactly i need to get and how much it will cost so i can budget and plan accordingly...

thanks
Title: Re: several 4.0 head swap questions
Post by: shanebo on December 14, 2011, 02:39:34 AM
Tougeagle had a great write up on his conversion and he included all the prices on it. There are several plug and play kits Hesco and Mopar being 2 off the top of my head, but both are very expensive. Here is the link...check out page 5. http://forums.amceaglenest.com/index.php?topic=21335.30
Title: Re: several 4.0 head swap questions
Post by: BenM on December 14, 2011, 12:21:40 PM
It's my opinion that you should swap the cam - a 4.0 stock cam will do nicely on a budget. That will require new lifters too, and it's a good time to replace your timing chain since they get a little sloppy after 100,000 miles.

The only necessary parts are a couple of head bolts, possibly a sleeve set if you have the smaller bolts, the exhaust manifold, and some exhaust pipe bending to clear the front differential. Don't forget gaskets.

You need to notch the intake to fit higher and mess with some brackets, but that's just some time, not money. You're throttle assembly rides along on the intake and just needs the kickdown adjusted for the slight difference.

The only thing to beware of is the exposed casting holes that don't always seal.

It's not a direct swap, but there are no expensive parts or hidden problems.
Title: Re: several 4.0 head swap questions
Post by: kajsdf on December 15, 2011, 12:27:59 AM
just did the timing chain a few weeks ago, actually.

probably better to get new lifters and cam, correct?

and final question is....the jeep 4.0 liter is the same as the 4.0 offered in eagles, right?  the one listed in the engine manual supplement we have as a download on the nest?
Title: Re: several 4.0 head swap questions
Post by: mudkicker715 on December 15, 2011, 06:25:54 AM
Eagles never had a 4.0.

Your better off getting a h.o. head and cam from a iirc a 91 to 95 jeep.
Title: Re: several 4.0 head swap questions
Post by: kajsdf on December 15, 2011, 11:05:18 AM
whoops, meant cherokee etc...just listed in the same engine manual.

might be a dumb question, but is there enough room to remove the cam without pulling the engine?
Title: Re: several 4.0 head swap questions
Post by: mudkicker715 on December 15, 2011, 11:16:31 AM
Any good at cutting and welding.
Title: Re: several 4.0 head swap questions
Post by: kajsdf on December 15, 2011, 11:20:34 AM
nope...i guess that means i'd have to pull it...
Title: Re: several 4.0 head swap questions
Post by: kajsdf on December 15, 2011, 08:03:03 PM
looks like i'll be able to go pick up most if not all the parts tomorrow.  i'm having trouble locating the exhaust manifold.  will any from 87-95 work or do i need to use the renix one?
Title: Re: several 4.0 head swap questions
Post by: mudkicker715 on December 15, 2011, 08:45:13 PM
here we go again. Haha. None work from a 4.0 are you good at cutting and welding. Sorry the 4.0 l flange needs help to fit.

I cut and welded my stroker to fit true duals. Took a few hours of trial cut weld cut weld. Blah blah. Still not happy with one side it gets knocked off from time to time.
Title: Re: several 4.0 head swap questions
Post by: kajsdf on December 15, 2011, 09:02:07 PM
oh, the write-ups seem to indicate the 4.0 exhaust manifold will fit but i would have to bend the exhaust piping itself to fit
Title: Re: several 4.0 head swap questions
Post by: carguy87 on December 28, 2011, 10:45:26 PM
The 91-95 exhaust header from the 4.0L will fit with a 4.0L head swap.  But you will have to modify the exhaust pipe to mate up to it, and you will also have to modify the front diff bracket by the pinion that goes to the engine block so it doesn't hit.
Title: Re: several 4.0 head swap questions
Post by: Baskinator on February 01, 2012, 01:09:20 AM
So basically kajsdf, a 4.0 head swap in itself will require the following parts:

-4.0l cylinder head (preferably the 7120 casting off a 91-95 Jeep)
-4.0l exhaust manifold (decent stainless one can be bought off the 'bay for about $90)
-JB weld and water soluble packing peanuts to seal off certain unnecessary water jackets in the head
-new head bolts
-new head gasket, intake/exhaust gasket, flange gasket, possibly valve cover gasket, and possibly water outlet gasket

and it will also require modifications to the exhaust pipe that attaches to the new manifold. Your intake can remain the same, and the 4.0 swap by itself will give you about 40hp more, maybe up to 50 if you clean everything up thoroughly so air can flow better. A lot of the real hp and reliability comes from fuel injection, but it is not necessary for just this conversion. You can also stick with the stock carburetor if you desire, but if it's a Carter I would suggest at least rebuilding it to make sure nothing's clogged up. Not too difficult to do with a $20 kit.

All in all, it will probably cost $300-$500, depending mostly on how cheap you can get the cylinder head for. Start your search at the junk yard or the 'List site. Hot tank at your local shop would probably be another $20 or $30, machining maybe $100 or so?

The write-up on the Eaglepedia is nice, but it is way too cluttered and confusing for those just looking to do the head swap without fuel injection. It could also use some more pictures to be less confusing.
Title: Re: several 4.0 head swap questions
Post by: Baskinator on February 01, 2012, 08:54:41 AM
Holy cow, I can't believe that thing's not pouring out coolant without those water jackets being sealed up. They just go directly on top of the gasket.
Title: Re: several 4.0 head swap questions
Post by: carnuck on February 02, 2012, 07:29:42 PM
Some 4.2 blocks are wider than others (depending on the year and where they were cast) but the stroker is a 4.0L block AND head combo. No leaks to stop up!
Title: Re: several 4.0 head swap questions
Post by: Baskinator on February 02, 2012, 09:25:16 PM
Oh, right. Didn't realize it was the 4.0 block he was talking about haha. Nevermind...
Title: Re: several 4.0 head swap questions
Post by: kajsdf on February 03, 2012, 11:36:49 AM
i've already got the head and exhaust picked up, got them off someone's 4.0 for $100 altogether. i dropped it off at the machine shop a d they found one crack in the valve seat of one of the cylinders...it isn't leaking anything, but it still makes me a little nervous. i went ahead and threw in some new lifters since it looks like the swap is on hold for a bit. i did the 2150 +tfi/whatever you want to call it already so i'll be running better in the meantime. thank you all for the suggestions and advice
Title: Re: several 4.0 head swap questions
Post by: vangremlin on May 19, 2013, 02:21:38 PM
whoops, meant cherokee etc...just listed in the same engine manual.

might be a dumb question, but is there enough room to remove the cam without pulling the engine?

Sorry to resurrect an old thread, but just wanted to make sure it was on record that you can remove the cam without pulling the engine. 
Title: Re: several 4.0 head swap questions
Post by: kajsdf on June 09, 2013, 04:10:43 PM
yes, pull the head and lifters. also need to pull radiator and ac condenser if you have it, then timing set etc. can pull can through the front end where radiator was before, just be careful not to bang the cam up when removing and reinstalling
Title: Re: several 4.0 head swap questions
Post by: Eagleearl on June 10, 2013, 12:11:19 PM
Also the 4.0 cam has no fuel pump lobe so you would need to go with an electric fuel pump. I think you could find an aftermarket 4.2 cam with similar statistics to the 4.0 cam if you are running a carb.
Title: Re: several 4.0 head swap questions
Post by: vangremlin on June 11, 2013, 08:48:45 PM
Also the 4.0 cam has no fuel pump lobe so you would need to go with an electric fuel pump. I think you could find an aftermarket 4.2 cam with similar statistics to the 4.0 cam if you are running a carb.

I went with this one, not a real radical cam but an upgrade from stock and still has the fuel pump lobe.

Comp Cam CL68-115-4