Keeping my 85 alive.

[mudkicker715]

Chirps tire into 3rd. 1st spins 2nd squeals. Won't even mention 4ths top end. Been 3 years 20k miles.

[GRONK]

The 4.0 head swap is simple, inexpensive and very nice.  More power, better economy and cheaper than rebuilding existing head.  I have done this on many Jeeps and have always been pleased.  I recommend ensuring you have a good fuel delivery system 1st.  No need for EFI, too many great bolt on options, next I alwaysupgrade the ignition.  TFI or HEI (I prefer TFI) then I always do the head (once everything is dialed and set)  Of course if you think you need head work, that might change the order of priorities.  I have the complete head write-up/install instructions.  email me if you want it.

[mudkicker715]

Mine is msd 6a sparked.

[tougeagle]

I am curios what the benefit of just a 4.0 head would be?So as always I appreciate all the input i can get.
Thanks

A 4.0L head would give a great performance boost, as what I have heard from many people who have done it.  Some have left the stock carb on with the 258 intake, and took off the fuel injection, and some have went the extra mile and put in a computer and fuel injection.  But like I said before, that would involve tapping into your current Eagle wiring harness and putting in a crank position sensor, and so forth.

But the 4.0L head would give a great boost of power, as the inlet ports are at a smooth angle, whereas the 4.2L head inlet ports are at a 90 degree angle.  It allows better flow of the air/fuel mixture, better atomization of the fuel, and better compression.

The 4.0L exhaust manifold would bolt up along with your 258 intake if you choose to put a carb on. (Some have had difficulties making them come together, others not)

Tougeagle really knows what he's talking about.  He has done the 4.0L head swap.  Here is write up by him on the Eaglepedia: Tougeagle's 4.0L Head Swap

I have been lagging behind in getting all the pictures posted in it Sorry about that... until I get them done you can refer to the projects section to find them.

[tougeagle]

Chirps tire into 3rd. 1st spins 2nd squeals. Won't even mention 4ths top end. Been 3 years 20k miles.

I read that you have to overbore to 4.9 or 5.0 liters to use 4.0 pistons. Is that true?

[mudkicker715]

Why? Think about it. 4.0 block..................... throw in the crank and rods from a 4.2..................plug and play. Pistons stay natural to the 4.0. The only change is the lower end so...................... bearings and hopefully you miked to your crank.


So nothing to buy in a sense except bearings to match your crank.

Now that is the cheap way. Mine had work to check and polish crank line bore balance head work. I bought no new parts cept the head work. I just needed a polish to my crank. So I really could have used the old bearings on the crank.

[tougeagle]

Why? Think about it. 4.0 block..................... throw in the crank and rods from a 4.2..................plug and play. Pistons stay natural to the 4.0. The only change is the lower end so...................... bearings and hopefully you miked to your crank.


So nothing to buy in a sense except bearings to match your crank.

Now that is the cheap way. Mine had work to check and polish crank line bore balance head work. I bought no new parts cept the head work. I just needed a polish to my crank. So I really could have used the old bearings on the crank.

Oh, nevermind, I'm thinking 4.2 block. Of course the 4.0 pistons fit right in. Using the 4.0 rods requires more expensive modifications.

still far more expensive than a head swap if rebuilding the motor properly.

[tougeagle]

I am looking at a 4.2 out of a 87 Wrangler should every thing be the same?

I don't have the "milky" oil, I changed it to get a good look at it.  But there is steam building up under the valve cover and a lot of moister in the exhaust,is there something else that would cause this?

yes, there is residual moisture in the oil from blowby, as the products of combustion are CO2 and water, and that is seen when lifting the cap on a hot engine sometimes. Moisture in the exhaust is the result of a good burn. This does not in any way suggest that you have a bad head gasket. you need to do a compression test. Check your coolant when cold for the smell of exhaust or gasoline.

[eagle503]

I really appreciate all the input guys.
     I feel like the best place for me to start is the carb's stepper motor since it is not working and could  be the source of my heat issue. Can i get the carb to function with out the stepper? The N-U-T-T-E-R bypass tells me to disconnect it is why I ask. I took the stepper out and sprayed it down with carb cleaner then put it back in, nothing seemed wrong with it but i have no idea how it would look and act if it was rite. Does the stepper come apart? I did not want to force it and brake it so i didn't try to hard. It is Still not working.
    I found this jeep web site that explains how to build this diagnostic tool http://home.sprynet.com/~dale02/diagtool.htm I think it will be helpful if I build one. At least then I will know if the stepper has input.
Well that's where I'm at.
Thanks Guys!

[tougeagle]

Gather as much data as you can before replacing parts, a good diagnosis goes a long way. As does a multimeter. Extremely valuable for diagnosing stuff like this as it will tell you if the circuit is complete or not, and whether or not you have power where you should or shouldn't.

[shanebo]

Hesco has a crank position sensor adapter....of course Hesco=Expensive..its around $280.00! But I gotta say they sure have alot of cool stuff for these things.

[eagle503]

I have power to the plug for the stepper, but the stepper is bad I pulled it out and it wont move in and out without a lot of effort. I put it in the mid range and put it back in and it seems to run a little better but still hot n rough. I have a post about the stepper going more info there...
http://forums.amceaglenest.com/index.php?topic=35643.msg284901#msg284901