Cracked cylinder head, help me decide what to fix

Trevlaw said:
130k on the WJ, 160k on mine. Not the best deal, but I searched from Redding, CA to Seattle yesterday and there's nothing for sale that is compatible with my 02, just lots of 90's motors. I'm hesitant about handing over that much as well, but I spoke to the general manager and he was clear about being able to get a refund if I wasn't happy with compression, more of a deposit I guess since they still have to pull the motor from the rig.
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130k isn't bad if it was taken care of. My wife's old 2000 WJ had over 280k on the motor. Did you look on facesuck marketplace?
I think out west people want more $$$ for parts. I just checked facesuck in my location and there are three 4.0 engines for sale at 500.00 or less.

The 4.0 I picked up last summer is for a stroker build. The engine had less than 100k on it. When I tore it down, I found it to be in excellent condition. I should have probably put it back together and run it.
 
williambmac said:
130k isn't bad if it was taken care of. My wife's old 2000 WJ had over 280k on the motor. Did you look on facesuck marketplace?
I think out west people want more $$$ for parts. I just checked facesuck in my location and there are three 4.0 engines for sale at 500.00 or less.

The 4.0 I picked up last summer is for a stroker build. The engine had less than 100k on it. When I tore it down, I found it to be in excellent condition. I should have probably put it back together and run it.
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Yeah I've searched everything, and yeah parts seem to go for a premium here.

Not sure how much I should worry about the skirts on my motor's Pistons. Lately when I start it cold it will idle fine, but if I try drive without it starting to get to temp it'll have a pretty good ticking/slapping sound for about 30 seconds then it goes away and never does it when it's warm. Was thinking maybe the drain back valve in the filter I got was bad( Wix 1085) and it was a lifter that bled down, but it only does it under load, not idle, so not quite sure if it's a lifter or piston slap. I've had the usual lifter tick for the last year or so, but this noise is about twice as loud
 
In regards to just replacing the cylinder head:

If you pull a junkyard TUPY head, GET IT MAGNAFLUXED. I pulled one off an 03 WJ and it was cracked already.

The TUPY castings aren't really any more immune from what I've seen. Basically luck of the draw. Poor design of the head is the issue. Exhaust ports next to each other and ported too much. Just find a good one and treat it nicely. The pre 2000 heads were really the better design sadly.
 
Well, I sort of pulled the trigger on the junk yard motor, they're going to pull it from the rig and get back to me with compression numbers on Monday. If that's all good I'll plan on getting them swapped out soon. I'll have to swap most of my accessories on to the new motor. Will probably pull the valve cover and oil pan to put fresh gaskets on and check it out some more, gonna grab a new set of motor mounts too as well.

Thinking this should do it for parts, anyone see anything I'm missing?
Valve Cover gasket
Oil Pan gasket
Rear main Seal
Injector O-rings
Motor Mounts (Mopar)
Transmission Kick Down Cable( mine is broken)
Water Pump Gasket
May do a new Mopar water pump
Intake/Exhaust Manifold Gasket
Oil Filter
Thermostat and gasket
 
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Trevlaw said:
Well, I sort of pulled the trigger on the junk yard motor, they're going to pull it from the rig and get back to me with compression numbers on Monday. If that's all good I'll plan on getting them swapped out soon. I'll have to swap most of my accessories on to the new motor. Will probably pull the valve cover and oil pan to put fresh gaskets on and check it out some more, gonna grab a new set of motor mounts too as well.

Thinking this should do it for parts, anyone see anything I'm missing?
Valve Cover gasket
Oil Pan gasket
Rear main Seal
Injector O-rings
Motor Mounts (Mopar)
Transmission Kick Down Cable( mine is broken)
Water Pump Gasket
May do a new Mopar water pump
Intake/Exhaust Manifold Gasket
Oil Filter
Thermostat and gasket
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Make sure that the head on the new motor is good. Would suck to drop the motor in and have head issues. Refer to my post above about my luck with a WJ TUPY casting. In my opinion, its best to find a jeep in the yard that was crashed badly. Then you know that it was running good enough to crash at a higher speed XD

Things to think about that you may have already considered/solved: How does all of the serpentine belt stuff work out? Are the thermostat and water pump housings clocked the same for a WJ and a TJ?

You probably know this, but just to mention it. When you do the water pump and thermostat, rent/borrow one of those vacuum coolant fillers from autozone/oriellys to both check for leaks with the new gaskets and to ensure that there are no air bubbles. TJs are a pain in the butt to get all the air out of.
 
iamloganjames said:
Make sure that the head on the new motor is good. Would suck to drop the motor in and have head issues. Refer to my post above about my luck with a WJ TUPY casting. In my opinion, its best to find a jeep in the yard that was crashed badly. Then you know that it was running good enough to crash at a higher speed XD

Things to think about that you may have already considered/solved: How does all of the serpentine belt stuff work out? Are the thermostat and water pump housings clocked the same for a WJ and a TJ?

You probably know this, but just to mention it. When you do the water pump and thermostat, rent/borrow one of those vacuum coolant fillers from autozone/oriellys to both check for leaks with the new gaskets and to ensure that there are no air bubbles. TJs are a pain in the butt to get all the air out of.
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The oil in the motor looked really good and still full. The car was definitely wrecked due to a crash, hard hit on the driver front corner.

Haven't checked the thermostat, but the TJ and WJ share the same water pump. Everything looked pretty much the same as the TJ.

Idle at startup sounded better than my motor so hopefully that's a good sign lol
 
Trevlaw said:
My TJ is a 2002 4.0 with 160k on the clock. Unfortunately I must have an earlier 02 as I have the 0331 head, not the TUPY casting. Over the last several months I've been chasing some misfire, cam and crank codes. Ended up replacing the cam and crank sensors with NOS Mopar sensors and that seemed to clear up those codes. Though lately I've been getting seemingly random P0301's and nothing else, and over the past several tanks of gas my mileage has dropped considerably, about 130 miles per tank vs the 180-200 I've gotten since I've owned it over the last 7 years.

It's had a very slow coolant loss for a little while, fixed some coolant leaks and thought I was good. Pulled plugs and did a compression and leak down test.

Compression test
Dry Wet (~3/4 Tbsp Motor Oil)
#1 115 115
#2 130 130
#3 140 140
#4 130 140-145
#5 135 145
#6 130 150

Leak Down Test
#1 60% Air heard from dipstick and radiator cap
#2 40% Air heard from dipstick and radiator cap
#3 30% Dipstick only
#4 33% Dipstick only
#5 30% Dipstick only
#6 27% Dipstick only

So I think that confirms I've got either a cracked head or head gasket issue between # 1 and 2. I had a bad fan clutch over last summer, and there was a day when it was 115* outside, couldn't keep the motor from hitting 220-230, got stuck on the highway and it just wanted to get hotter the slower I went. Anyways, that probably didn't help me out, but the Jeep is my DD, so if I'm gonna have to pull the head off I don't really want to dick around with dragging a possibly cracked head to a machine shop.

I'm curious what everyone things about a replacement Clearwater head? I've seen decent reviews of them on here, but some older posts on other forums and reviews they have don't seem too hot, but there's not any TUPY heads for sale local to me to have cleaned up. I figure the least I need to do is a head gasket and head swap and that would get me up and running like normal again.

But, in my research I've also discovered that apparently Chrysler has a TSB or something a long time ago about the 98 - 02 IIRC 4.0's having poor quality pistons or something along those lines, leading to them being more prone to piston skirt failure.

So, I figure with the head off that could be a good opportunity to replace pistons and rings assuming my cylinders aren't worn too bad, I do have a bore gauge I would be able to inspect them with. I'd probably do rod and main bearings at that point too, but I've done those before on an older 4.2 in the vehicle and didn't have any issues, so that wouldn't be too big of a deal. Then I'd basically have new everything except for the block, crank, cam and cam bearings.

It's a slippery slope though, and an expensive one too, but I'd really hate to just do a new head, have a skirt break in the next couple years and scrap my block, especially since right now I at least have the convenience of still being able to drive it while I gather parts and get a plan worked out.

There's not much of this work I don't feel comfortable doing, I'm just not setup for any of the machine work that could be involved, so that would get contracted out, but all of the disassembly, inspection and reassembly will be done by me and with my work schedule I have 4 days off every week to get it done.

What say the group, any ideas on what I should or shouldn't replace and any ideas on where to get a new or reman head?
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Is it engine swap time ? I mean have you considered it ?
Like I mean V8
• depending on your long term plan for your DD
 
DETOUR said:
Is it engine swap time ? I mean have you considered it ?
Like I mean V8
• depending on your long term plan for your DD
Click to expand...
Definitely not, I'm up to 3 years on my current LS swap into my J10 and I'm still not done, no way do I want to deal with two of them at once lol.
 
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Trevlaw said:
The oil in the motor looked really good and still full. The car was definitely wrecked due to a crash, hard hit on the driver front corner.

Haven't checked the thermostat, but the TJ and WJ share the same water pump. Everything looked pretty much the same as the TJ.

Idle at startup sounded better than my motor so hopefully that's a good sign lol
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sounds like a good fit. Getting to see the oil that was in it, is huge. most the big yards by me drain ALL the fluids as a "safety measure" for the environment. Even if they pulled the motor for sale up front. :rolleyes:
 
Well, got started on the motor swap today. So far so good, no major issues, the upper bell housing bolts are damn near impossible to get to though.

Was swapping some parts between motors and noticed that there's a lot of oil or carbon buildup in the intake runners on the manifold and the head of the new motor compared to mine though. The runners on the new motor have quite a bit of buildup, however the back sides of the valves appear to be spotless, whereas on my old motor the runners are nearly spotless and I can see bare metal, but the back sides of the valves do have some buildup. Not quite sure what to make of it.

My grandpa thinks the valve seals on the new motor have to be leaking to allow the oil to be getting into the intake. My coworker who is a pretty good former mechanic doesn't think it's the seals, but rather the breathers on the valve cover allowing oil fumes in and building up, though I'm not sure why my higher miles motor doesn't have the same issue.

My grandpa has a tool we can use to swap in some new seals without pulling the head, but it'll set me back about 6 hours for the parts to show up.

Anyone have any ideas? Was planning on just cleaning it up real good and vacuuming the buildup out and running it. Not much of a choice at this point anyways.

Every intake port on the head and intake looks like this, the head side is probably a bit worse
IMG_20220131_182514203_HDR.jpg
 
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Started to replace the rear main seal on the new motor. The main bearing in the cap has a couple of small particles embedded in it, but the crank journal is fine, no scarring and it's still nice and smooth. Should I try to remove the particles in the bearing, or just let it be and run it?

IMG_20220201_122640597_HDR.jpg
IMG_20220201_122711420_HDR.jpg
 
Got the swap all done on Thursday and drove it an hour home. Seems to run pretty good, better after I reset the pcm yesterday. No oil leaks so far and probably had about 30ish hours of labor into the swap with my grandpa helping. Not nearly as much ticking and knocking on startup as the old motor.

Pretty sure the oil pump drive assembly is the source of the metal fragments I found in the old motor. Not sure if a bearing in it failed or what, but it looks like the gear on the assembly was being pushed upwards from the force of it meshing with the cam gear, causing it to run against the stem of the assembly above it, depositing metal fragments into my oil for who knows how long. Going to pull that assembly on Monday to get a better look, the gear teeth on it and the cam were both fairly pitted and worn.

That assembly was a Napa replacement with roughly 100k on it. Had swapped the Mopar one out way back when I first got the jeep as my dad and I thought it was bad due to the ticking noise it makes, but I think that was just normal for it. Wish I had that Mopar one now...

I know the later models had a lot of issues with the OPDA's, but I thought I'd be free and clear of that with the earlier 2002 setup. Not opposed to replacing it every so often to prevent it from happening again, but not sure how good of an idea it is to introduce a new oil pump drive gear to a worn cam gear.

Anyways, it's running good now, so can't complain too much
 
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Anybody know a ball park time on how long it takes the pcm to get back to normal after resetting it?

Did a few hundred miles yesterday and it was mostly good, but a few hiccups. The new motor feels pretty much normal around town and on flat roads, but some of the steeper inclines around here it feels pretty gutless. Like I'll be doing 65 at the base of the incline and as I'm going up I'll have it full throttle just to try and maintain speed, whereas my old motor when it was good I could accelerate up pretty much any incline. Every now and then it performs like that, but I can't figure out the cause of the difference. I know on the inclines when I give it that much throttle the pcm is switching into Open Loop-Drive, but I'm not really sure what that means or if it's supposed to be doing that.

The other thing that happened, I was driving some back roads at 60 or so on my way to the first Craigslist stop, pulled up to his driveway and shut it off just after doing 60 for 20 miles or so. Loaded up my purchase and started it ten minutes later and it seems like the engine heat soaks itself from shutting down so soon after driving hard. While driving my temps never rose above 201* on my scanner, but after starting it up again it's at like 210-215 on the gauge, idles real low and sort of stumbles like it's going to stall until it runs for maybe 30 seconds and cools back down. My old motor would do that sometimes on real hot days, but yesterday was only 60* out.

And also, the damn rear main started leaking after 5 days of being dry, so that blows.

@Jerry Bransford I remember a recent post of yours about oil and rear main links, but can't find it again. What was the oil you had good luck switching to, to try and slow or stop a rear main leak?
 
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