head gasket problems

hey everyone, bit of a problem ever since i got my heep.

when i bought it i had to put a cam, lifters, timing chain & gears, have the head resurfaced, new water pump, thermostat, and more that i cant think of rght now (thats only counting what i put into it when i first gotit, not counting what i put into it overthe past 2 years.)

since i have had it the head gasket has blown 3 times. twice by me and then really bad by someone that was going to buy it and then gave it back.

my question is...what am i doing wrong? i do the gasket the way the book says, i always have the head surfaced and checked, i always torque the bolts to the right amount, but it keeps blowing them. and now the machine shop says that the head is milled down to far to use and i need to get a new one.

by the way, anyone got a used or rebuilt head for sale?

any help wuld be appriciated!!

A few things that may be relevant. The head bolts should only be reused once, they stretch. The bolt holes in the deck can pull and build a ridge and may need to be hit with a counter sink bit, this can keep the head from seating all the way. Check and see if the alignment dowels are bottoming out, seat the head first without the gasket and check to see if it sits flat Check the deck for straight as well as the head, maybe the deck is poorly milled from the factory or has been distorted from head tightening.
Every time you shave the head, you lower the chamber CC'S and raise the compression a bit.

When the head gasket goes what happens? Water in the cylinders, cylinder to cylinder, oil out the sides?

P 4529242 is the recommended gasket, though I have had good luck with Mr. Gasket (composite) on the 4.2s.

Mine often sprung oil leaks, I used the Mr. Gasket composite head gasket (old school) and a light coat of Permatex just around the outside edge and the oil passages. Most manuals frown on sealer being used on the head gasket.
Fel Pro has a coated gasket many people swear by, some of there stuff works well some doesn't. I've never tried there head gasket.
I've put heads back on with well over the allowable clearance and not had them leak. Added another five pounds of torque and prayed.

I've had good luck with Fel-Pro head gaskets. I'd prefer Victor/Reinz, but they're a pain to find.

use No Sealer if you're using the Fel-Pro gasket! Five gets you ten that the Fel-Pro gasket will fail if you use a sealer on it! However, material finish is usually critical to head gasket sealing - you don't want it to be too smooth. cf. my responses in another recent head gasket thread for how to clean and prep the surface...

twice i got water in the first cyl.

the last time it was blown so bad that there was oil on the side of the block.

im confused about the alignment dowels. mine havent had any since i first bought the jeep. i thought it was odd that it didnt have any. is it supposed to?

its an xj thing said:

twice i got water in the first cyl.

the last time it was blown so bad that there was oil on the side of the block.

im confused about the alignment dowels. mine havent had any since i first bought the jeep. i thought it was odd that it didnt have any. is it supposed to?

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i believe you need to be careful with one of the head bolts near the front cylinder becasue it goes into the water jacket of the block.

also check out this thread http://naxja.org/forum/showthread.php?t=946582&highlight=head+bolts

89xj said:

i believe you need to be careful with one of the head bolts near the front cylinder becasue it goes into the water jacket of the block.

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#11 - driver's side front. That's the odd one you're thinking of - it gets threads coated with PTFE paste (no tape! Plumber's "pipe dope" works fine...) and torqued to 100 pound-feet (instead of 110.)

Alignment dowels are nice, but not strictly necessary. You can make them yourself out of 1/2"-13 threaded rod - cut two to a useful length, slot the tops, and use a screwdriver to remove once the head is down. The "dowel" is more like a "sleeve" around a screw hole - but it's more of a convenience, and I've seen engines that didn't have them from the factory.

yeah, my 4.0 didnt have them and im sure that i was probably the first one to tear into that engine so theres not much of a chance that they got lost.

did renix engines not have them, or just some of them didnt have them, or what? im confused, because my retarded friend was telling me that the engine needs them and i kept telling him that it never had any.

its an xj thing said:

yeah, my 4.0 didnt have them and im sure that i was probably the first one to tear into that engine so theres not much of a chance that they got lost.

did renix engines not have them, or just some of them didnt have them, or what? im confused, because my retarded friend was telling me that the engine needs them and i kept telling him that it never had any.

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Some do, some don't. They're not strictly necessary (as I said) - they're just a convenience. You can do without them quite nicely (I've torn into three RENIX rigs - two didn't have alignment sleeves, and I removed them from the third.)

The key element in head gasket sealing overall is surface finish - both in terms of flatness (no warping) and in actual finish (can't be too smooth or too rough.) A fine Scotch-Brite wheel will work wonders for cleaning up and prepping the deck surface.

Don't forget to seal the #11 screw - I believe the screw in the same location on the 150ci four also wants the same treatment.

Oh - and I forgot, the 242ci six head screws are a modification of the "Torque To Yield" screws used on Diesels. They're good for two torque cycles, then they're shot. They'll usually snap on a third, but sometimes they'll just stretch. If they stretch, they'll leak. If the engine runs with a stretched screw, the head will usually warp (less common with iron than aluminum, but it's always a possibility.)

ok, thanks for all the information. i really appriciate it. now, where would you u recommend getting a reman. head?

should i just go junk yard searching and have it done, or should i order a new one from someone?

5-90 hit it on the head on the surface prep it is VERY important

Id go to a junk yard and pull a couple off the quick and nasty way to peek at them find one that looks good to you and then go get it checked. get the warrenty form the yard so if it ends up bad you can get another one easyer.

this may be a dumb question but is the jeep overheating when the gaskets go or is it just the gasket failing?

it overheats alot, and blows steam. everytime it blows it always leaks into the 1st cyl.

its an xj thing said:

it overheats alot, and blows steam. everytime it blows it always leaks into the 1st cyl.

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did you do this?

Don't forget to seal the #11 screw - I believe the screw in the same location on the 150ci four also wants the same treatment.


#11 - driver's side front. That's the odd one you're thinking of - it gets threads coated with PTFE paste (no tape! Plumber's "pipe dope" works fine...) and torqued to 100 pound-feet (instead of 110.)

its an xj thing said:

it overheats alot, and blows steam. everytime it blows it always leaks into the 1st cyl.

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You need to find out why it is overheating in the first place . Otherwise get used to replacing head gaskets .

A milled head needs a head gasket with more thickness
otherwise the compression ratio gets raised.

what part of the gasket is blowing out? If its blowing out around the cylinder thats the sure sign the compression is too high

stretched bolts can be to blame as well, good for 2 full torques only

wonder if you can put studs in a 4.0 block...

Stretched bolts were my first thought as well.

The quality/type of the HG you've been using as well? If its an aluminum head, the new Multi-Layer Steel HG are the ones to use.

Use the recommendation of the HG manufacturer for SEALANT. Like mentioned, the Fel-Pro & Victor Rense HG come with a Neoprene rubber coating that is the sealant, using an additional sealant will interfere with sealant coating the manufacturer put on the HG.

I used the Chrysler MLS kit for my little Neon R/T, that has a horrible reputation for blowing HG. I used the exact spray sealant they recommended in the instructions. Its been 110k miles of hard driving and that HG is still holding strong.

How about torque sequence, have you checked your doing it right? Haven't done a Jeep Head, but in the other cars I've done, you usually start at a lower torque and progressively increase torque each time you go through the torque sequence. Its usually NOT just one torque in the sequence once.

well from what yo guys are saying, i need to replace the head bolts. where can i get them?

i always torque them in the 3 stages im msupposed to, and in the right order with the drivers side front one having the stuff put on it. it always blows across the water jacket into te first cyl.

im thinking that the head bolts have been used to many times.

its an xj thing said:

well from what yo guys are saying, i need to replace the head bolts. where can i get them?

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Got mine here:

http://headbolts.com/amc.html