Spoonman

Well after all this time I finally decided to track down a jy cylinder head for my 99 cherokee 4.0L.
I plan to go on Friday to pick it up.I have not seen the head but the jy gives a 90 day warranty on the head and it is only $100 which as long as it is in good shape is a great deal in my opinion.
Any way my question is what should I look for besides the obvious damage since I am a little skeptical about major parts like this coming from a jy?
The guy from the jy says that they only do a visual check so no pressure tests or anything for cracks so I am going to see how much my local machine shop will charge to just check for cracks and hopefully they can also test the valves.

Out of all the local junk yards here I only found 2 that had a head, the one I am going to get is half hour to 45 minutes away and they guy seemed real nice and double checked the casting number for me, the other is almost 2 hours away ( not so local lol ) and the lady there was nice and all but didnt want to be bothered to double check the casting numbers on hand for me so I go to the closer one .

LegalizeFreedom

Is this a 0331 head?

tjwalker

If it is an 0331 head that is not 2003 or newer, don't buy it.

The 00-01 XJ head (0331) has a casting defect between cylinders 3-4, which make it susceptible to cracking. And if the crack isn't found quickly, the coolant will mix into the oil and destroy the engine bearings. Seriously, walk away from that head if it is an 0331 unless it has the word TUPY stamped on it between cylinders 3-4 (this shows that it is one of the redesigned 0331 heads, which are okay).

So it is REALLY important to know the casting number! An 0630 which is what the 99 came with, is a good head. But you would definitely want to take it to a machine shop and have them pressure test for cracks, verify straightness, and test the internals. That is money WELL SPENT>

Spoonman

Sorry I should have mentioned that it is the 0630 head,and the 0630 is what was on my jeep.
It may be a bit too late for the engine damage because the original head did crack but I am just now going to get the head for it and have not looked much further into the engine and am just hoping that the bottom end is not trashed.

The 0331 issue is the main reason I asked that they check the castings for me plus I was not sure which of the casting numbers were interchangeable with what year etc etc.

Thanks for your input though.

Spoonman

Is there a list somewhere of bolt information for these engines? like thread pitch etc etc so I can get the proper taps and dies to chase all the threads and bolts. It would also be helpful to know in case I need to replace any nuts and or bolts.
I of course will be using new head bolts but I will still need to chase the bolt holes in the block for them as well as all the other bolts I will probably just re use.

Spoonman

I read that you can not use new lifters with an old cam? I wanted to get new push rods and maybe new lifters but not sure about getting a new cam so is what I read true or what? what about using the stock cam and lifters with new push rods?
What would happen if you use all the old components but put the push rods in the wrong place?I think I ordered the push rods correctly when I removed them but I didnt put them in like a piece of cardboard so I am not 100% sure that they are all where they originally were.

BRN2KL

Spoonman, you can use new lifters with an old cam. I just would not do it. I dont recall all the technical reasons as to why this is not recommended, but why do you think you need new lifters? There is not a performance or mechanical reason for just replacing lifters unless you run solid lifters. There again, u dont need solid lifters unless you plan on keeping ur I6 at about 5k RPM for the next few weeks. Same question about the pushrods: why replace them? Are any of them bent? If so the PR aint the problem, u would need to perform major surgery on that motor. If u are replacing a cracked head at a slow pace, obviously the jeep isn't a DD, pull the motor and rebuild the thing. If u can scratch your butt and chew gum you can rebuild a motor. The machine work is critical in a rebuild. Find a good auto machine shop, not NAPA (sorry guys), and have them machine the block. The rebuild is easy at that point, buy a rebuild manual and follow the instructions. As far as putting PRs back in the wrong spot, ehhh, not really a big deal. when u put the head back on, u will have to adjust the valve lash. easy to do, just takes a little time and patience. If this is getting to overwhelming lemme know. Spoonman, instead of me hijacking your thread and turning it into "how to install a head thread" just PM me if u r interested in finishing this conversation.

BRN2KL

Buy a thread chaser set from sears or some place. It sounds like u are going to be at this jeep thing for awhile, and the thread chaser set is going to be more useful than 1 or 2 taps and dies. Just an opinion

Spoonman

As far as the rebuild of the entire engine, money is the only issue and time right now since winter is approaching and I would like to have this thing on the road by then.
I was just thinking about replacing the lifters,push rods and rockers for 5 reasons
1: The engine has 200k on it
2: The engine was overheated,cracked head and has coolant through out
3: It is clear that the po's neglected the oil change interval because there is tons of sludge in the top end
4: I dont know if I ordered the push rods properly when I pulled the head ( stupid me )
5: They are pretty cheap $$ to replace

I have not checked yet if any of the push rods are bent, but if any of them are is it ok to just use new push rods with the old lifters and rockers? If so I might just clean everything else up and get a new set of push rods rather than use the old ones.

I still need to pull the oil pan and clean and inspect everything down there before putting this thing back together. I am hoping that I wont have to go any further into the engine.I want to pull the lifters from their bores and clean all the sludge out of the top end too.
I might end up having to pull the engine and doing a rebuild even though I dont want to because the cylinders have some rust on them. I will take pics this weekend to post.

Spoonman

Oh and by the way I thought that valve lash was non adjustable on these engines? its a '99

BRN2KL

If u want to pull the lifters, make sure that u note location and orientation of each lifter. Lifters wear on cam lobes, and u will have catastrophic problems, (read bent PR, seized lifter, lobe destroyed on cam) if u misplace or miss the orientation of the lifter on the cam when reinstalling the lifters. At that point a rebuild will be inevitable.
As for the rust in the cylinders, motor oil and 000 steel wool will take care of the surface rust. Normally I would not recommend this, but u stated u have 200K on the motor with missed oil changes in the motors history: your cylinders are definitely worn and out of round, u are not going to do any real further damage by rubbing the rust out of the cylinder walls with steel wool. If u haven't noticed, u are undoubtedly using some oil in your motor.

I would run the motor until it dies after the head swap. Be careful of rod bearing failure, it will put the rod through your block. JB weld wont fix that. U will have a wasted block at that point, so if u have time and money, rebuild the motor in the spring/summer time frame. Strokers are nice, but u will not see significant improvement until about 4K rpm.

As for the valve lash, no it is not adjustable, because the I6 uses hydraulic flat tappets, AKA hydraulic lifters. But initial lash still needs to be set.

I hope this has answered some questions and I hope u can interpret my dry sense of humor. Also, if u have more questions, lemme know. I will help in any way I can. Most of my engine experience is high HP Small Block Chevy motors.

Spoonman

Thanks for the info its much appreciated.
I know it isn't a compression test or anything but for what its worth I'm thinking that even though there is 200k on the clock the cylinders are in good shape.
One reason being there is no ridge at the top of any of the cylinders and the other is that it sat with coolant in 3 of the cylinders for 2 to 3 months before I started working on it and ( I haven't pulled the oil pan yet ) I don't think any of it leaked past the rings.
Now I could be wrong and I'm sure that some of it had to leak no matter what and I will find out for sure when I get off of my rear and get further into the engine but I'm hoping for the best.

I think that it would be best to pull the lifters to clean them up and I want to get as much of the sludge out of the engine as I can. You said orientation, don't the lifters have a concave bottom on them which makes them spin on the cam lobe? Or are you saying they have to be placed exactly the way they come out? I know each is mated to their own cam lobes by now and need to go back to that specific lobe but I am a bit confused by you saying they have to be orientated the same as well.

I am not sure about using oil because I bought the jeep in this condition for $200 expecting to only have to replace the head gasket, so I have never actually drove it.When I went to look at it to decide if I was going to purchase it, it did start and run and it actually ran nice and no smoke except for the rough idle which I figured was due to most likely a blown HG.Of course the day I went to put it on the trailer it wouldn't start though lol.

Bottom line I need to get off of my butt and get that oil pan off and have a look at those bearings before I can decide exactly what I am going to do and how far I am going to rip into this engine.

I think I might have asked before in a previous post but is it possible to pull all the main caps one at a time and inspect the mains without pulling the engine?

As for the valve lash I just bought a haynes manual,I know they aren't the best but its better than nothing so I will just have to follow their steps when I get to assembly.

Spoonman

By the way here is a pic of part of the old head and one where you can see into the lifter cavity just to show the sludge I speak of.

And yes I may be heading into some pitting on the cylinder walls of the #5 an #6 cylinders.I need to get that cleaned up asap.

BRN2KL

Spoonman the concave bottom lifters are roller lifters. The 4.0 uses flat bottom lifters. The 4.0 doesn't need roller lifters cuz jeep motors don't need aggressive cam lift. As for the rust in the top of the cylinders u are going to have to do something to remove the rust before u start the motor. 000 steel wool is not that aggressive and any by product can be wiped away with a shop towel. The fact that ur cylinders are capable of holding water/coolant is a good sign that the cylinders are not egg shaped. But, unless somewhere in the history a new motor went into that jeep, guaranteed the cylinders are out of round. When u run a motor heat and pressure will allow oil to move past the top ring on your cylinder. A static motor is not a running motor, the variables will change the characteristics. Hope that made sense.

U can pull the main bearing caps individually and look for bearing wear, but I can save u some trouble, the bearings are worn. I have never pulled the main caps without doing a complete disassembly, so I don't know what else u could accomplish by doing this. U can and should drop the oil pan and clean thoroughly. Replace the gasket at that time as well. U are replacing the head, and if u clean out the oil pan, and the bottom end while the pan is off, u should have been able to address the sludge problem for the most part.

Haynes manuals are not the best, but if u can out perform the manual, u are going to be very well versed in jeep repair, and a major contributor to the advance tech section of this forum.

I think that covers everything u have asked or addresses thus far. I am not the end all of jeep anything, so if someone else on here has info please share it. I will be checking back to see if anything else is added.

BRN2KL

I didn't answer the question about orientation. Yes, pull lifters one at a time and mark 12 o'clock position. Use a spring loaded punch to mark lifter and lifter galley, while the lifter is still resting on the cam. This will insure lifters go back in the galley oriented in the appropriate way and resting on the lobe as they have been for the past 200k miles. Hope that made sense.