So here goes the 4.0 head swap.......
-4.0 head, cast No. 7120 or 0630 ( difference being, from what I gather, the 7120 has a coolant sender port in the back of the head. Some 0630 heads have this also but mine did not. The 7120 also has a minor difference in flow, but you'd probably never know the difference. Also if you use a 4.2L intake, you'll have additional ports to run a sensor, plus the one in the thermostat housing, and the original in the block). You'll find the number dead center on the top of the head on the drivers side. KEEP THE HEAD BOLTS BECAUSE THEY WILL WORK (72-75 CJ's)
-Valve cover off donor vehicle( if you see a oil cap off one, grab that ***** since all of them in the yard were gone!)
-Try and grab the coolant sensor and plug for the thermostat housing too.
-Newer 258 intake. There are several options, but the cheapest is to find the 2 barrel aluminum off of an 80's CJ or possibly other amc vehicles. EXAMINE THE INTAKE VERY WELL! MINE HAD A SMALL CRACK THAT I DIN'T SEE WHICH KILLED ME LATER! Also check the egr valve to see if it is good. Mine wasn't and it created a vacuum leak.
-96 or newer 4.0L exhaust. The older ones crack from what I hear. These ones have the ribbed tubes on the number 1 and 6 cylinder tubes.
-Retaining washer cups and bolts from intake/exhaust manifold
-Thick, grade 8 washers larger than the retaining cup washers (width not thick)
-Gasket kit from donor vehicle (new)
-Spark plugs from 4.0L (new)
- Copper gasket rtv spray
-About 2' of the exhaust tubing off the donor vehicle. Try and include the o2 port if possible.
-High temp JB weld (get the big box)
-Packing peanuts that dissolve in water
-Alcohol (rubbing type, although booze type will also be required)
-RTV, RTV,and RTV
Alright......So this was a pain in the a$$, I'm not going to lie. Mostly it was a bunch of little stuff that I'll explain as we go along. First you need the donor parts. I pulled mine off a 96 cherokee (0630) that looked brand new. If you're parts hunting, look at the condition of the jeep engine bay to see how well it was maintained. My head looked brand new. It was a glossy black, had 0 oil saturation on the valve cover gasket, and the intake/exhaust gasket still looked new. The thermostat housing also showed some rtv around the edges. Most jeep heads will look rusty or corroded or covered in an oily grime. It's a good idea just to give her a good once over before you decide to pull it, just so you know what you're getting. I didn't take mine in to the shop for a valve job. There ended up being almost no carbon on the valves and in the chamber and it appeared to be in standards using a straight edge and a feeler gauge, but we'll see. I highly recommend taking it to a shop. Head cost me $40, exhaust was pre pulled and cost me $25 for the exhaust manifold and tube.
SIDE NOTE: WHEN PULLING PARTS AT A JUNKYARD, LEAVE AS MUCH ATTACHED TO EACH OTHER AND TELL THEM IT'S WHAT YOU'RE BUYING. EXAMPLE: EXHAUST MANIFOLD ATTACHED TO THE TUBE "YES MA'AM, ONE EXHAUST MANIFOLD". SOMETIMES THEY WON'T KNOW THE DIFFERENCE AND IT'LL SAVE YOU A FEW BUCKS!!!
Once you have the head home, you'll need to put the packing peanuts in the water coolant ports to make a base for the JB weld. There are several ways of doing this and the choice is yours. The 4.0L head gasket does not have holes for the water jackets. I used JB weld for piece of mind. Some weld them, some drill them out and put a plug in. Your a big boy, you do what you think is right. I don't think there is a wrong way but everyone knows someone who did something and all hell broke loose. These are the websites I used for the water jackets:
I used the alcohol to clean any excess JB weld off the head surface.
Wait until the day before or day of to clean the head (if you are doing it yourself) to help prevent any rust. I used a brass wire wheel on a drill and made sure to plug the ports when using it to prevent anything from getting in.
Mock bolt the intake and exhaust manifolds up to see how much you'll need to grind the intake down. On the lower corners of the intake, the manifolds will hit and prevent the intake ports from sitting level with the head ports. The dowel pins in the block will also not line up with the holes in the intake. I ground down the corners (about 1/8"-1/4") and cut the loop where the original dowel pins would've gone. I cut just enough so that after grinding the corners, the bottom of the ports lined up and the old dowel pin holes sat on top of the new dowels in the head.
You'll also most likely have to grind about 1/4" of an inch off the exhaust manifold where the nut goes onto the stud by the number one cylinder/port. I didn't read anything about this and I couldn't get my head to align correctly due to the exhaust manifold hitting the water pump. Also under the intake is an egr to exhaust manifold tube. You'll need to cap this off along with the one under the carburetor ( I'll planned on dealing with it and all the other vacuum stuff when I do the TBI install).
After everything looks good, go ahead and paint whatever you want. You'll need the one piece intake/exhaust gasket that came with the kit. Hose it down wit the copper gasket maker then install. Place the exhaust manifold on, then the intake. Use the bigger washers you got to place under the retaining cups that were on the original manifold bolts. You may need to flatten one side of the washers in some places to help them seat against the intake. Use the "offroad-review" link above for torque sequence and specs.
Remove all the old, heavy a$$ cast iron crap off your 258 and sell on craigslist or ebay. Make sure buyer pays shipping. If you get all excited when working on your jeep when you get new parts and can't wait to get them on, resulting in some dumba$$ mistake, pay attention to this: DRAIN YOUR COOLING SYSTEM!!!! or else you'll fill your cylinders with coolant.......don't ask. On the bright side, I know my rings hold a pretty good seal!
Clean and prep your block. I used a razor and a brass wire wheel. If you use a wire wheel, make sure you seal off the cylinders and lifter valley so you don't get any brass wires/crap in the there. It'll score the cylinder walls and plug up your oil pump and then you'll have to explain to your wife why you have to rebuild and engine now.....
This is where you call your buddy to help lift he head on, unless you have retard strength like me
. put the head gasket down and place line up the head and bolt down using 4.0L head specs. The same pattern is used as whats in your Chilton or Haynes repair manual. If you don't have one by now, you really should've. The specs are also on the "offroad-review" link above.
Use the 258 pushrods. The valve train is self adjusting so you just need to install the pushrods and torque the rockers down to 19 ft/lbs. (http://oljeep.com/JeepEngines.pdf
If you are like me and trying to keep this on the cheap side, use the 2' of tubing to cut, turn, and re-splice the exhaust together. Once I get everything else done, I'll take my Jeep in and get it professionally done, but that's after I do the suspension.
here's where I went out on a limb. If you did a HEI upgrade, they say to gap your plugs to .045-.055. When you install a 4.0L, the factory plugs are at .035. When you increase compression, from what I understand, you need a smaller gap. Davis Unified ( where I got the cap,rotor, coil kit from) recommends .055-.065 upon installing their kit. I called them to see what they recommended and they said around .050-.055 at least. I went with .050 and it seemed to work.
And that's pretty much it! Most say it'll take 5-10 hours to install. It took me a week because of the exhaust hitting the water pump, then the vacuum leak from the intake not seating (fixed using copper coat), then the hair line crack that ended up breaking off a corner of the intake manifold, then trouble shooting vacuum leaks to the faulty EGR valve. Oh and also trying to find find brass fittings and the damn coolant sender that goes in the block! I don't know if you guys have had this problem but trying to go back to the factory gauge from an after market gauge they gave me a smaller sender unit that doesn't match the block thread. I used a 1/8" to 3/8" NPT adapter to get it back in. That and the po had the wrong gauges.
She runs and maintains temp so all is well so far. I haven't had a chance to run her around yet, probably start doing that today.
Hopefully I didn't forget anything but if I did, or there is some confusion, I'd be happy to help.
A few other notes:
Thermostat and Thermostat housing: I left the 195 degree thermostat in there and installed a new gasket (which didn't come with my head gasket kit) To get it to seal, I used RTV, gasket, RTV. The radiator hose is a pain to get past the new valve cover and if you don't get it all the way down along with the hose clamp, it'll leak.
The later model 258 aluminum manifold is a "wet" manifold meaning it flows the coolant through the manifold. for now, I am not running the the coolant through there. I will when I do the Contour fan upgrade.
I plan on using the coolant sensors in the manifold and the thermostat housing for the contour fan and TBI upgrades. That's why I returned to the factory gauges. It also looks cleaner.
They are having a half off deal at the pick and pulls this weekend. My next install is going to be the power steering install, followed by upgrading the alternator to a CS144, then the contour fan upgrade. Probably going to nab those parts there if I can.
For the power steering, I already grabbed all the brackets and pulley off a 70 something AMC Hornet with a 258. The bracket does fit the 4.0 head so I can install the pump on the passenger side with no problems. Looks like this will be a plug and play type thing (mostly). I'll start including pic's, as I noticed there is an "upload Image" button I hadn't seen before and I figure it'll be more helpful. I know when I found them, they were for me.