DanInOH

As the title states, I'm in the middle of a head gasket job. Dropped off the head at the machine shop today to get it fluxed and (provided no cracks) a valve job, etc.

Since I've got the head out and wide open access to a lot of stuff now, I'm wondering what you all think I should replace/service since its easy access (other than the head gasket, intake/exhaust mani gasket, and valve cover gasket, head bolts)

I'm thinking upper and lower radiator hoses, as well as the heater core hoses. Did a water pump and t-stat last year around this time. Just trying to think ahead and do a little preventative maintenence since the XJ is gettin up there in miles and who knows what was done before I picked it up.

Plugs, wires, cap and rotor were replaced before I did compression check to determine it was head gasket. Everything but plugs looked due for replacement anyway, so it wasn't money wasted.

It's a '99 XJ w/ 199k miles.

DanInOH

Got a call from the machine shop...my head has a crack in it. Visited him after work, and sure enough, it does. It's in a strange spot. I'll try and get a picture up tomorrow. I've got the 0630 casting. Shop has a rebuilt 0331 for $275. I trust the work, just don't trust the casting. Its never been cracked as he says he doesn't fuss with rebuilds if they have been. I think an 01 XJ was the donor, so methinks this was before the casting issue was corrected. I'm gonna try and hit up the pick'n'pull this weekend and get another 0630 or 7120 if they're still in the donor vehicles. Yard has a 31 day return policy, so I'm only out $25 for the magnafluxing if the head turns out to be cracked.

DeathWobble

A comp cam for more torque. Since you got it mostly apart anyway.

tjwalker

I agree with your logic on the 0331 head.

You absolutely, under no conditions, want to put an 0331 head on your XJ UNLESS it is an 03 or newer, when Chrysler got their heads from a different foundry (TUPY).

03 and newer 0331 heads are just fine. The TUPY head is very hardy.

If it truly is a TUPY head, it will have the word TUPY stamped on the head between cylinders 3 and 4.

You could call the shop and ask them if it is a TUPY head. If it is, you would be fine.

If it is NOT, keep looking!! The 0331 head (until 03) had a casting defect between cylinders 3-4 which make it very prone to cracking, especially if there is an engine overheat.

If you get stuck and can't find one, Clearwater Cylinder Head and Alabama Cylinder Head are two very reputable sources for heads. Lots of good references on both of these businesses. Would be about $400 or so shipped to your door.

Good luck!

tannerp89

push rods? they're cheap
timing chain and gears? while you have it tore apart, why not

blasto9000

I'm looking to repair my head gasket issue next weekend. So if you're still looking for suggestions, replace the fuel injector seals too. I bought the seal kit from rockauto.com for around $1.50 per injector.

DanInOH

tjwalker, It's not a TUPY head :-( Although there stands a small chance it might be. Machine shop guy didn't see anything, but I'm not sure he knew what he was looking for exactly...

DeathWobble, I'll probably hold off on this until I do my stroker build. Still trying to source a decent motor off of craigslist so I can just swap-and-go. This project is on the list, but not practical right now. I'm planning on doing a decent inspection on my XJ to make sure its not starting to rot. Don't wanna dump a bunch of time and money into something that's rusting.

Tanner, my push rods looked ok. Straight and no pitting. I'm thinking about the timing chain and gears, but I'm not sure as I may be doing a stroker build sometime in the future. I don't want to dump a bunch of money into my motor just to dump a bunch of money into the stroker, although I suppose if they're still low-mileage and I end up using the same block I could just reuse.

Blasto9000, I was thinking about doing the FI o-rings. Thanks for the link, I'll check it out. If you've got a 2nd vehicle and time, from my recent experience, I'd recommend finding a machine shop near you and get your head magnafluxed. It's relatively cheap piece-of-mind and can pick up cracks you can't see with your eye. ESPECIALLY if you have the 0331 head.

I feel like I'm practically an expert on XJ 4.0s now after all my research. I'm going to try and get an 0630 casting (for simplicity's sake - same as my original) but may go with 7120 (and associated exhaust manifold - I know some of these are prone to cracking, so I'll pay extra attention) if I can't source an 0630. Going to the pick'n'pull this upcoming Saturday to see what I can find. Shame they can't tell me what's left in the vehicles, only which vehicles they have. There's several XJs and ZJs to pick from...all either 0630 or 7120 castings. Just gonna suck pullin' the head in the cold...long johns and mechanix gloves FTW!

$40 bucks for the head, $30 for the manifold. Shop cost is $25 for the flux and $150 to rebuild...So I'm out $215 for the head if all works out. Cheaper than a re-man (which uses repaired heads) or new from ACH or CCH. Pick'n'pull yard also has a 31 day return policy, so I suppose I could return the head if its found to be cracked...

Thanks for all the input guys!!

UserID6095

You could swap out the lifters.

blasto9000

Dan - thanks for the advice. Yeah, I know you're right, but I’m still dreading and sort of in denial about what I’m going to find with that head. ;-)

The Jeep’s not my daily driver so I can keep it off the road for extended machine work. But it’s still a pain in the butt to have the garage tied up for 1-2 weeks. Maybe I’ll just pick up a Marshall rebuilt head so it’s ready to just slap on and go. They’re not awfully expensive (around $330 plus core) but I find it somewhat demeaning to have to buy a rebuilt head when I’m perfectly capable of doing it myself. ;-) But $330 is hard to beat considering I’d be out almost that much on a DIY after buying the core and putting new parts and time into it.

Rikkadog

Might be a good idea but if you do I would go with a new cam too. Otherwise just inspect them and if no excessive wear take them apart, clean the sludge out of them, make sure the springs are OK and all the oil ports a free, and make sure that they go back into the same places that they came out of.

DanInOH

My valvetrain was unbelievably clean. Guess routine oil changes pay off. I went to the Cincinnati You-Pull-&-Pay this past Saturday and found an 0631 casting on a 97 ZJ (mileage unknown) that was involved in a roll-over. Man, those fools must have never heard of an oil change, that thing was a sludge-box. Dropped the head off at the machine shop Saturday, heard from him today. No cracks and it will be ready tomorrow! So, I'm out $215 for a remanufactured head of known quality, vs a $270 one from ebay that was probably built using a repaired head (eeek!) or a $500 new head from one of the various companies.

I've decided to check the motor & tranny mounts and replace if necessary, new o-rings for injectors, new timing gears and chain. Also I need to pick up a new oil pressure sending unit (I'm 99% mine is bad, reads 40psi before I even turn the engine on -- this doesn't jive right -- will hook up mechanical first just to double-check), and probably going to replace the CPS while I'm in there since its super easy access right now and I know about the potential problems those can cause when they go bad. Not cheap, but good for piece of mind.

Since I'm bone stock right now, I think money would be better spent on a proper lift and rubber vs cam & lifters. The 4.0 is fairly stout stock, and no extra gains will compensate for lack of clearance.

Thanks again guys for all the input, its greatly appreciated!