89 Minor Rebuild

[WrenchedXJ]

I've been in ownership of my xj for just over a year now. Bought it with 230k miles with a bad tranny. Replaced the tranny and its gone through quite some changes since ive had it, more functionality freebie mods(fender trimming, cut and fold, etc.). A cracked freeze plug has put it out of commission. Originally, I was just going to replace the freeze plugs and be done. With now 232k original miles and unknown maintenance in the past, I'll be going a little deeper, but not major(money restricts). This is a designated trail truck that may see 2-3k miles a year. Keep a side note that within the next two years, my plans are to swap in a GM 5.3 or stroker. With no oil consumption, I have decided on a top end build only. Here is what I have planned.

Cooling
-Flow cooler High Flow Water pump
-Stant 195* Stat
-Open System radiator from newer XJ
-Taurus fans
-Freeze Plugs

Engine
-Take head to machine shop to have cleaned, pressure tested, and the valves seated.
-inspect camshaft for wear, replace as necessary.
-inspect cylinder walls for wear
-replace from head gasket up on seals/gaskets
-power steering pump
-starter
-rear main seal

Fuel system
-new fuel filter


A few things I am unsure about though. I would like to put some 4 port fuel injectors in to help, just havent decided on which ones. The other thing that needs to be replaced are motor mounts. Should I go with the OEM mounts or the daystar poly? One other thing it does every once in a while is lose oil pressure. It started to happen after I submersed my jeep in a mud hole and had a mud line at the oil filter. No valve noises when the level drops, possibly just the sending unit? Anything else I should consider?

 

[joe_peters]

The later 4-hole disc type injectors will provide better atomization of the air/fuel mixture and a smoother idle. Neon or Ford (Bosch) injectors. See Rainman's table in this thread: http://www.naxja.org/forum/showthread.php?t=1027854 and read JP Magazine's article on fireproofing the 4.0: http://www.jpmagazine.com/techarticles/engine/154_0811_preventing_jeep_engine_fires/index.html

UNLESS you like lots of vibration in your hands, I would not recommend Poly engine mounts. Check out Brown Dog, their mounts can go either way, so if you try poly and hate it you can convert to natural rubber.

I would throw a mechanical oil pressure gauge on it and confirm the pressure, but most likely it is the sender or the wire is loose on it.

Seriously, the 4.0 can go over 300k miles easily. Unless there was a reason--compression, coolant loss, etc., I wouldn't pull the head, all the rest of your list is reasonable.

 

[WrenchedXJ]

forgot to mention that. two issues I am stepping into to fix. Coolant loss, not sure where it goes, my jeep doesnt mark its territory(besides the oil from the rear main), no smoking from...hmm...caught me in mid sentence. I was going to say it doesnt exhaust white smoke, but on my way back from a weekend wheeling/camping trip, I got about 45 minutes from home, and it was smoking, not when on the gas, but when I let off. being tired and ready to just get home to take a shower and eat something other than grilled cheese from a gas station , I freaked, pulled over and checked for leaks, no leaks, oil was at its level, didnt check coolant as it wasnt overheating. didnt smell burning oil or coolant. is it possible for the head gasket to only leak SOMEtimes? the other issue is HORRIBLE gas mileage. Sure I have a locked rear end, running 31's with stock 3.55 gears, but ive been getting 10mpg across the board, actually get worse mph on the interstate it seems.

 

[joe_peters]

Ok, more to the story.

Your headgasket can leak just enough that coolant is going out the exhaust and you can't see it.

Any chance that "off throttle" smoke might have been a little bluish? You could run a compression test, a leak down test, and a coolant hydrocarbon test to confirm a headgasket issue.

In fact, I would run a compression best before pulling head. Any low reading cylinders shoot a little oil into it and run the test again--if the readings come up you need rings.

 

[WrenchedXJ]

I'll be sure to check that out. I'll be doing all the work after christmas. I'll have the whole week off on vacation and the shop will finally be somewhat cleared out. I'll post my progress and do a semi-write up. just got to remember to take pictures.

 

[WrenchedXJ]

ended up helping a friend build a storage shed over my vacation, but its alright, the lean-to off the side the the shed will house his boat. Free work=unlimited boat rides. haha. after I got off work yesterday, I went and grabbed the tow truck and brought it to the shop. First step was to check compression. The results were(from cyl 1 to 6): 120, 135, 140, 130, 120, 120. Happy with the test, I continued to tear into it. ended up pulling the head, intake mani, and exhaust mani at the same time, must easier to disassemble on the bench. After seeing the condition on the cylinder walls and the non-factory seals, I came to the conclusion that this engine has been rebuild before. Which answers my question of "how is this thing still running with 232k miles?". Sent the head to the machine shop today to have it cleaned, pressure tested, and the valve seals installed. The head bolts all came out with just a little tug, didn't strip or break, thankfully. I was going to go ahead and look into replacing the head bolts, but cant find them anywhere except for the dealer. Also seeing the condition that the engine is in and seeing that it has been rebuilt, im questioning myself if I really need to spend over $100 on some bolts.

 

[joe_peters]

IF the bolts have already be reused, then you are asking for trouble if you try and use them again.

They should have been painted on top if the last person that had the head off did the job correctly.

What happens is the head bolts stretch when torqued. Combine the stretching plus possibly one or more head surfacing and you end up with a head that won't seal (the head depth has been reduced and the head bolts are too long) or one of the head bolts will let go on you.

Complete head bolt set $44.95: http://headbolts.com/Jeep-AMC-232-244-258-4.0-engine-head-bolts.html

 

[WrenchedXJ]

Im not sure if they've been re-used or not. I didnt see any paint on the heads. I think for $50, I can jusify the head bolts, just to let me sleep better at night. There are still a few places I havent checked. Im hoping to have it done by this saturday.

 

[joe_peters]

Ok.

Try searching on for headbolts or head bolts--seems to me somebody found them for under $40, seems like $36.95 wants to stick in my mind. Possibly they were Fel-Pro.

 

[WrenchedXJ]

1 question if you know it. It would make sense to me that they would be, but are all 4.0 head bolts the same? I can find head bolts for grand cherokees just not cherokees.

 

[joe_peters]

86-96 4.0 are the same, 1/2" bolts.

97-04 4.0 are the same, IIRC 7/16" bolts.

Not aware of any differences than that.

 

[magimerlin]

Any head bolts up to 1996 (meant for the XJ 4.0 motor)will work. I am using ones listed in the Fel-pro book listed for a 1995 (I think) set on both my 89'. The difference is that 2 of the head bolts will have a stud style top for the newer style valve cover gasket. Other than that they are the same length. The Fel-pro book does not list any for the Renix era motors but I can assure you that the ones up to 96 year model will work.

 

[WrenchedXJ]

Yea, I ordered head bolts for a 96 Grand Cherokee and figured I could at least try them. I received them, and it was a perfect match except for the two with the studs as you said. The plan was to finish up on Saturday morning, but things never get accomplished on time in my life. Also didnt help that me and my buddy went to Lowe's and Advanced Auto engineering snorkels. The plumbing specialist was quite confused when he saw the assembly and just kept walking by. I did end up finishing last night around 10. :clap: If it wasnt for a mild case of OCD, im sure it would have went a lot faster. Now, since I know I like pictures, Ill upload them all.

The old cluttered engine bay. I found it much easier to disconnect everything on the intake and exhaust manifold, unbolt the head, and remove as assembly. Same for installation. DO NOT forget to label your injectors, I thankfully remember to do so, but know of someone who didnt and now cant get his to run good. He claims it is something else, but Im willing to bet a weeks pay that its the injectors in the wrong place.

Just a 3.5" Rough Country on 31x10.50s

Old stock waterpump vs the new flowcooler.

on the lift about to go up. notice the back sitting higher. I had installed a wedge block to change the driveshaft angle making it not sit level, this is all about to be fixed.

Head off and off to the machine shop for cleaning and leak testing. starting the clean up a little bit and brighten the day(or night) up. yes...I know...not mopar orange. I had and extra can of chevy orange lying around from the 6.0 I just got done with, so decided to use it up.

New motor mounts in, freeze plugs out. I simply took a punch, tapped one side of the plug out until it twisted and grabbed them with the pliers. I thought only one was bad, try 5 had a least 1 pin hole in it, no wonder I was losing coolant. When I reinstalled then, I put a coat of RTV on the edge and tapped in with a large socket. then painted them to prevent rust. For the motor mounts, the drivers side is pretty straight forward, the passenger side, I had to remove the oil filter, loosen the OFA(simple terms, the oil filter screws into this). I loosened it enough to turn and get out of the way. jacked up the engine until the bolts came out. then put the new ones in. I just bought stock ones for now, brown dogs will be next, just wasnt in the budget this time around.

There is a little gap in the photos, I got a little excited about finishing it and didnt touch my phone. Sorry. :doh:

all cleaned up. Open style radiator installed with the factory reservoir. the orange line is just airline used for the coolant. Clogged the holes up in the airbox and put a breather in the valve cover. NO MORE OIL ON THE FILTER! awesome. reinstalled the dualling efans with rivets this time on new metal brackets, instead of self tap screws through plastic, much cleaner. Yes, I have a serpentine belt diagram drawn in sharpie. haha. had to do it when I moved the alternator.

Just made a simple mounting bracket for the reservoir. had to bend the bracket a little bit, didnt think the hood was going to be a problem when in stalled, but it ended up being so.

Here is a little bit better of a angle. I had already relocated and upgraded the alternator. The alternator is the 136amp from a Grand Cherokee. Dual e-fans which actually sit better since the engine mounts. I was almost concerned that my hood wasn't going to go back down from seeing how much higher my engine sat now.

Installed 1 3/4" Coil spacers in the front to level it. Of course having the lift made everything much simpler, but am sure the same thing can be accomplished with a jack and coil compressor . I unbolted the LCA, UCA, the track bar, and brake lines, and just lifted up until I could pop the coils out, installed the spacers, then the coils, and buttoned everything up.

After finding the correct location for each plug on the distributor cap, it fired right up. It runs very well. While I had the intake and exhaust manifolds off, I brought out my die grinder and ported the intake out just a little bit. Just matched it to the side on the head, ended up being about an 1/8. wish I had pictures, but that was during the excited moment. Monster probably didnt help any. So in conclusion, I replaced the 5 freeze plugs on the side, the 1 in the head, Im sure there is one in the lower block, but I'll tackle that another day when I feel like pulling the tranny back. I replaced the water pump with the flowcooler, the thermostat with a Stant 195* superstat, upgraded to a 94 XJ cooling system. New radiator and heater hoses. all gaskets associated. fuel filter, air filter, and coil spacers. next up, finishing my front sway bar discos. Thank you Joe and merlin for your help and if any one has any questions on anything, just let me know.