99 XJ Getting Head Cleaned

[shmicah]

99 xj 4.0L with 188k miles

I have some questions about getting the head cleaned/rebuilt. I've done some digging around but still feel unsure of it all. My engine is pretty much completely disassembled at the moment, so I've had several people tell me to remove the head and have it cleaned/rebuilt while I'm at it.

I'm going off of this thread:
http://www.cherokeeforum.com/f67/cleaning-pulled-head-166981/

So, basically, remove the valve cover, then based off FSM I should see 2 Cylinder Head Bolts. Once I remove those, the whole head should come out as one giant block with the valves and springs and all attached? Like so:

So, then I just take that whole block as-is to a machinist and get it hot tanked, then checked for flatness. if warping >.002" then have them refinish it. Do I need to have them check anything for valves (like this three angle valve job I keep reading about?) Can I also just ask them to see what needs to be rebuilt (new seals, rings, whatever) and they would know what to do?

Once its all clean, get new cylinder head bolts and a head gasket then reinstall via FSM? Is there any painting that needs to be done? Someone in that thread said to paint it before reinstalling.

If you want it cleaned right take it to a head shop and get it hot tanked, not too expensive for just a clean job. Real simple just drop off and pick up throw a quick paint job on and be done. This will get all the internals ports and such.

What price should I expect to pay for just a cleaning? I would like to have this done as I doubt I will have the engine this far disassembled ever again, but I don't want to spend tons of money on it. I want to make sure I know what I'm doing when I go into the machinist so they don't smell green on me and start trying to scare money out of me.

 

[shmicah]

I see FSM says to remove capscrews, bridge and pivot assemblies and rocker arms. Remove push rod.

If my goal is to have it all cleaned and/or rebuilt, is this true? Or is this the FSM being super specific?

 

[gradon]

I'm pretty sure everything has to be removed to get hot tanked cause the valve seals wouldn't survive. Get a valve job and new seals while you are at it.


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[shmicah]

Just called a local shop. They quoted about 250-300 for cleaning, crack check, and resurface. Then will go from there depending on work done.

2 year 6400 mile warranty

Sounds good. He also told me to break it down to just the valve train so that answers that (in case other people search this)

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[Ecomike]

I paid $200 in So. Houston 8 years ago to get the head done on one. I supplied the valve seals from the head gasket kit. $300 sounds high, unless they do special work on valve guides or need a core to replace a bad head.

Why are you rebuilding it?

 

[shmicah]

I guess I will call around a few more places. This place is just so close to my house and very highly rated.

I have been redoing practically everything in my XJ lately (snowball effect!). It's currently already sitting with nothing attached but the valve cover, so I figured its a great time to have the head cleaned and valve work done. It's gonna be down for another couple of weeks so why not?


My understanding is a cleaning and valve work will bring new life to the head. When I say rebuild, I am probably using the wrong terminology. I more want it cleaned and worn parts replaced. I'm not looking to have the whole thing redone unless they find something bad.

I'm in Austin by the way.

 

[Ecomike]

Ask them what the $250 includes.

 

[md21722]

Places vary on pricing. I had a local guy tell me $300-350 rattling off a list of industry standard phases and it would take 2 weeks. I found a guy that told me he doesn't really like hot tanking them would do it by hand for $135 and would also take two weeks. His service area was spread out over tens of thousands of square miles stretching into 2 adjacent states. He reminded me of the good old boys I used to take stuff to before I moved. Some quick searching came up with only positive comments about him, others were so-so. I gave him the job and its been fine. He does use a computer controlled machine to deck the heads. Said he's never seen a straight six Jeep head that wasn't warped. Some will tell you they can take heads off one engine and put it on another without issue. In my case the head was warped and/or the head gasket blew. I did compression checks before pulling the head and after I put it back on after he went through it and got another 25-30 psi... In my experience on a couple of 4.0's by 160,000 you will get better compression and eliminate other problems by having the head gone through. Whether or not you will "feel" the difference depends. YMMV.

 

[xcm]

Some will tell you they can take heads off one engine and put it on another without issue.

For statistics, im 0 for 2 on this front, Wont be trying again.

One of the guys i had do work for me, put my 4.0 head on a machine for like 2 seconds, lifted it up and showed me the high/low spots... it looked super wavy and inconsistent, probably somewhat matching the last block....

 

[tjmotter]

A couple of things to note:

1) While there are a couple of head bolts under the valve cover, there are a lot more around the exterior edge of the head (14 in total if I recall correctly). The hardest to remove is the one closest to the drivers footbox at the rear. If you are going to tackle this I recommend you buy a 3/8" power bar and you will need some deep metric sockets for it. I say 3/8" because I couldn't get a 1/2" drive in there.

2) You should plan to replace the head bolts. Some people get away with using them again but part of the process of torquing them down is designed to stretch the bolt so the manufacturer will typically recommend replacing them every time you remove the head

3) one of those bolts extends into the water jacket (I don't recall which one) so you need to apply thread sealant on that one.

5) cut a piece of cardboard and cut 12 "x" marks in it with an knife. Then mark each "x" from 1 to 12 with a pen. When you remove the push rods, place them in order into this cardboard so that you can put them back in the same spot. You should find a way to keep each valves parts segregated like this. Some people use an egg carton for this while others use baggies. Regardless, over time, rockers, valves, retainers and locks tend to mesh together over time and you don't want to mix them up.

4) once you have the head off, clean up isn't really that hard. Using a valve spring compressor like this https://www.summitracing.com/parts/wmr-w89409/overview/ allows you to remove the valves pretty easily after which you can use a wire wheel to clean each of them up. Once clean, I reinstall each of them and do a quick wiggle check to see if any have excessive play. Not scientific but if they are really bad you can often tell. I recommend doing one at a time taking care to put each valve back in the same guide it came out of using the same rocker, valve spring, valve locks and retainers for each.

5) re-assembling the head isn't too bad. As I said above, put each valve back in the same guide you took it out of with the same springs, valve locks and retainers but at this point, install the new valve seals that will come with your head gasket.

I'm in Austin every other week and could lend you my valve spring compressor if you like. It worked like a champ when I did a backyard rebuild on my '90 XJ head.

HTH

 

[shmicah]

Appreciate the offer tjmotter. My car has been out of service for almost 2 months now, and I couldn't find a machine shop that would be able to complete the work in less than 2-3 weeks. I decided to say screw it and just get it back up and running. Appreciate everyone's input though.