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Uh Oh... cracked cylinder head!!

N

NeXJ

NAXJA Forum User
Location
Los Angeles
I'm in deep caca. I overheated my 98HO engine in my 92XJ the other night and it's sitting in the shop right now awaiting final diagnosis (the only other possibility is blown head gasket - but I KNOW it can't be that)...

I'm assuming my only option is to put in a replacement cylinder head...

what would YOU do?? I doubt my skills would be sufficient to deal with this task. I'm ASSUMING I'd have to either a) salvage one from somewhere and have it machined to match the block (they're all different, right?) exactly, or b) try to get a new engine (more expensive) or c) buy a used honda and part out my XJ...

PLEASE HELP!!
 
well if you're sure the head is trashed.. how badly did you overheat it? how many miles are on the ngine now? a remanufactured 4.0L installed at the dealer will be around $3000.... the head would most certainly be cheaper.. a junkyard head would also do the trick but i highly doudt the dealer would touch that installation.. it all depends on how much you want to spend on it and how much use it gets.. if its a daily driver i would throw a little more$$ at it for something better than a scrasp yard part... complete engines in "good" condition" can be had for less than $1000, maybe thats a better alternative.. and parting out the XJ is by no means an acceptable excuse to buy japanese....
mike
 
Wow... you can get me a 4.3 stroker for $500????? Great!!! Sign me up!! Because that's ALL that's in the budget - that's my RENT money, too!

Just goofing off - I mean no disrespect - I just don't have that kind of cash, or honestly - interest right now. I just need wheels to get to work. I've put alot of upgrades into my XJ in the past but I'm not even in that headspace right now.

Actually - this new forum format is GREAT - as soon as I posted, four other relevant cracked head stories popped up and I scored some great info. Looks like I can get a real deal at this site;

http://www.jeep-suv-and-parts.com/cylinder_heads/cherokee-1997-parts.html

But I'll be DAMNED if I can figure out where the heck they're located so I can figure out freight on the core. Might NOT be worth shipping.

Jonathan :wave:
 
Sid, thanks for the opinion. Yeah... I had a cooling system leak and underestimated how BAD it was. I ran dry (looks like) on the freeway from pasadena to hollywood and was SMOKING like a demon when I got off. I noticed a distinct loss of power and a knocking sound about 1/2 way along. The mech did a cylinder compression check and he thinks there's a crack between 3 and 4.

So it seems pretty bad. The big SHAME of it is that it's a BRAND NEW HO I put in just a few years back. I feel like an idiot for not checking up on the cooling system.

Anyway, I think the head replacement route is in order, if anything.

Jonathan
 
Not to sound like a schmuck, but at the very top, just to the left of center, is a "contact us" button. Try that...

You will have to make a few selections, but it looks like you'll pick your part type (cylinder head,) enquiry type (enquiry before ordering,) and select "general question." Or just call them - it's a toll-free number. It's amazing what you can find out by just asking...

Even if you take it in the shorts on the core (likely, welding heads isn't easy...) a price tag of $236 isn't too bad. Add in a head gasket set, head bolts, and a case of beer for one of your mates' labour and you're still in the clear! Hell, if you have any trade goods around, that could save you on labour - even at mate's rates (I've been known to work for trade before - you anywhere near the SF Bay Area? Got anything interesting?)

5-90
 
Actually, I'm at work and even being on the internet on the sly - so making a phone call like that is totally out of the question. I tried the 'contact us', 'information' AND FAQ links - NOTHING. NADA. ZIP. ZILCH. Yeah, I might try to find someone local to help. I've got some leftovers for barter, too. Rubicon track bar (new), BPEs, etc...
 
NeXJ said:
But I'll be DAMNED if I can figure out where the heck they're located so I can figure out freight on the core. Might NOT be worth shipping.
Why are you trying to figure out the freight yourself? If they are a "shipping" type of a company I am willing to bet $$ that they have provisions for shipping the core back and will be able to offer you a deal on that... .call them when you get a chance.
Click to expand...
Click to expand...
 
Well, actually based on past experience. I did a full AGR steering upgrade and to ship the cores back to TX would not have been worth the $5 difference between shipping and the core refund for the effort involved. Know what I mean?
 
NeXJ said:
Well, actually based on past experience. I did a full AGR steering upgrade and to ship the cores back to TX would not have been worth the $5 difference between shipping and the core refund for the effort involved. Know what I mean?
Click to expand...
Yes... but till you call you will NOT KNOW. Past experience is not necessarily an indication of future experiences even if dealing with the same company......
 
Oh... sorry - misunderstanding...?? Obviously I'm going to call them - I was just griping there was no ready info on the site. Clearly I can't really evaluate the situation until I have all the info... I was just trying to assess what I could at the time. I'll call at lunch and let ya know...

regards, J.

Kejtar said:
Yes... but till you call you will NOT KNOW. Past experience is not necessarily an indication of future experiences even if dealing with the same company......
Click to expand...
 
Back to the original problem:

Sorry to say this, but if you overheated the engine to the point that you even may have cracked the head, the engine is history. That degree of overheating will cause the piston rings to lose their temper. Once that happens, they don't seal. The engine will run, but it will be low on compression (and, therefore, low on power) and it will always use oil. LOTS of oil.

Been there, done that. Mine was in a competition event -- a hillclimb. The entire run was only about 90 seconds, if I remember correctly -- albeit 90 seconds up a mountain with the accelerator firmly planted to the firewall. A heater hose blew just as I left the starting line. Of course, none of the bird-brained course workers who saw the first 30 seconds of the run, while the car was pouring coolant all over the course, bothered to give me a red or black flag, so I ran the full course, blissfully unaware that I was cooking my engine.

I'll be surprised if the head is cracked, but I think you're in the market for an engine. Hit the junkyard listings. www.car-part.com
 
So... (okay here's where I demonstrate my ignorance) replacing the head alone will not suffice...? Are you saying I should replace the pistons themselves also (the piston RINGS are part of, or sit on, the pistons directly..? or am I mistaken?)...

throw me a bone.

Jonathan
 
Eagle once again shines his sagacity upon us...

I am inclined to agree with him - the good news here is that you can get "dye-check" kits you can use to check the cylinder, deck, and head for cracks for about $30 at a well-stocked parts house (if it wasn't finals week, I'd have thought of that earlier...) Something to put to work - they're simple to use.

Yes, the piston rings ride in grooves on the piston, and have enough spring tension to press against the inside of the cylinder bore - that's what creates the compression seal. Spring-tempered iron and steel are easy to wreck with temperature, and the temperatures required to crack an iron casting are rather high.

Approach - strip the head (you'll have to do that anyhow for the rering) and dye-check the head deck, block deck, and cylinder bores for cracks. Buy new rings and main/rod bearings (you'll have to replace the rods once you take them out for the rering, and the mains would be a good idea - though not strictly necessary) and assembly lube. If you are lucky, you'll only need to replace the head gasket. Second worst - have the head "decked" (shaved to a flat surface to correct warping.) Third worst - deck block AND head. Worst case - full-up rebuild.

I've had overheats before where I was fortunate and lost no more than the head gaskets and rings, so you could be lucky! I do highly suggest you begin doing your own work - jobs like this are good ways to learn the mysteries of the "screw job" from some mechs, and there are only three in the entire nation I trust (and I'm the only one in CA...)

5-90
 
dont mean to still the post for a quick question but it seemed like a good place to ask. i dunno if all but i think one of my head gaskets has been leaking oil all of my jeeps life when i have owned and part of when my dad owned it. I dont know what to do in this situatuon cuz i honestly havent had any problems with my engine ever. and im on 200,000 miles soon. does this call for a cylinder head replacement also or something else?
 
ok i am getting the feeling that all this tech advice.. be-it very good advice is a little beyond the tech ABILITIES of the member who posted the question.... there is nothing wrong with "learning as you go" and getting your hands dirty.. but my guess is he isn't up to performing these tear-down inspections... forgive me if i am perceiving this wrong.. not calling you a dumb-a$$.... i agree the engine could very well be salvaged with a good overhaul.. but i don't think he's going to do it himself.. a good used engine with a warranty is probably the most cost effective with the budget you indicated..
mike
 
That's probably about right. I certainly wouldn't be up to it myself. I did my own engine swap once - and it really wasn't fun. I don't really want to be doing that again. I can't say I didn't enjoy it - but I really DON'T have the time or interest right now to be doing that. Hell, I don't even have an adequate place to work. So I've got a local mechanic on it - though I have no intention of getting burned.

J.
 
sidriptide said:
a good used engine with a warranty is probably the most cost effective with the budget you indicated..
Click to expand...

I agree completely, and that was why I pointed out that the rings are probably de-tempered. It would be disappointing in the extreme to spend the money on replacing a head only to find that you have no compression and the engine burns oil like an old diesel. The engine in the vehicle I used as an example was pulled and scrapped, even though it still "ran." It wasn't worth fixing up.
 
dellstopjeep said:
dont mean to still the post for a quick question but it seemed like a good place to ask. i dunno if all but i think one of my head gaskets has been leaking oil all of my jeeps life when i have owned and part of when my dad owned it. I dont know what to do in this situatuon cuz i honestly havent had any problems with my engine ever. and im on 200,000 miles soon. does this call for a cylinder head replacement also or something else?
Click to expand...

What engine do you have?

The only XJ engine with head gaskets (plural) is the 2.8L V-6 used from 1984 thru 1986. Head gaskets don't usually leak oil. Perhaps you're thinking of the valve cover gasket, which is a comparatively simple replacement project.
 
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