I really wish I had good news to deliver about the manual 1994 Jeep Grand Cherokee “Holy Grail” I’ve been trying to fix for what seems like at least a decade. You’d think that buying a parts car and having a friend fly in from Wisconsin solely to help me wrench on this Jeep would lead to some kind of success. But alas, it all just led to failure. Slimy, stinky, rusty failure.
Two years ago, I intercepted two hyper-rare five-speed manual Jeep Grand Cherokees, bought them for $350 apiece, and then began the arduous process of trying to merge them into one functional Jeep. I’ve been buying up all sorts of parts to try to make that the ultimate Jeep Grand Cherokee ever built, but the truth is: I haven’t really gotten anywhere. Sure, I swapped a transmission from the rusty Jeep to the transmissionless, non-rusty one, but after that, the Jeep languished in my employee parking lot, where it acted as a safe haven for a cat giving birth to a litter of four kittens.
Last month, I promised that I’d partake in a last-ditch effort to get the Jeep ready for this year’s Easter Jeep Safari at the end of this month, but I can tell you based on this past weekend: That’s not happening. The Jeep is a basket case. It’s such a basket case, in fact, that I went ahead and bought the two-wheel drive version below as a parts Jeep to help me figure out what goes where, and to offer up any components that I might need – the entire exhaust system from the manifold back, for example.
The parts Jeep is much, much nicer than the red Jeep I towed across the country from Michigan, but it’s not an original five-speed 4×4 “Holy Grail.” Yes, I could swap the Grail’s drivetrain parts into the nicer two-wheel drive machine, but it wouldn’t feel right. Am I a bit of a romantic when it comes to rare cars? Yes. Does that romance bite me in the ass most of the time? Also yes.
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That ass-biting began with a broken exhaust stud. I was loosening the Jeep’s cracked exhaust manifold, and everything was working well. None of the bolts were stuck, and frankly, up until that point, every fastener was spinning right out without issue. But then, on the final exhaust stud — the rearmost one closest to the firewall — disaster struck:
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My solution involved removing the cylinder head, drilling a hole into the broken exhaust stud, and then using an EZ-Out screw extractor to zip the broken bolt-shank out of the head:
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I’m not entirely sure if breaking that stud was a bad thing or a blessing, because removing that cylinder head (after running a compression test; the engine scored very well) to address the broken stud led me to discover sludge. Lots of sludge:
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The sludge was possibly the result of contaminated oil sitting in the engine far too long, but whatever the cause, the case was severe. The sludge was almost solid, requiring me to dig it out with a flathead screwdriver. I managed to remove a shocking amount of sludge, mostly from under the valve cover and near where the lifters ride along the camshaft (in the block on the left side of the cylinder head-less deck).
I cleared out as much sludge as I could, but I’ve decided to clean or all the lifters as I’m concerned they may have sludge in them. And lord knows I don’t want to have to replace lifters after the cylinder head is back on. I’m also leaning towards pulling the oil pan to make sure nothing blocks the oil pickup tube, thereby jeopardizing engine lubrication.
Ever bench-pressed a gas tank? pic.twitter.com/0Qcb8kiGlh
— David Tracy (@davidntracy) March 11, 2024
The hits kept coming. With the help of Dustin and Autopian reader Jack, I lowered the Jeep’s gas tank to the ground to drain the old gas, only to find the black rubber seals had seemingly liquified and contaminated the fuel. I’m worried about what the rest of the fuel system looks like.
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So at this point, I’d broken an exhaust stud, removed the cylinder head to get better access, only to then discover alarming globs of sludge in the motor. I’d discovered a sludgy fuel system, and …
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This isn’t the same vehicle, it’s that World War II Jeep I bought for $85 last month. I figured since I had Dustin there, and the ZJ project had ground to a halt due to me needing to buy new gas tank rubber bits and snag new lifters (or clean the ones I have), I may as well take the cylinder head off the World War II Jeep I’d bought and then left outside in a rain storm with nothing covering the intake. I wanted to see if there was water in the cylinders, and what did I discover? Yes, yes there was.
Based on the video above, I’m inclined to believe cylinder two had water in it for well over a month, while cylinder four had only recently flooded, possibly due to my negligence. In any case, it looks like the motor is toast; I’ll try to free it up with automatic transmission fluid and a breaker bar, but that F-head Willys motor under my Jeep’s hood is likely nothing more than a paperweight. That’s OK because the plan is to put a Nissan Leaf motor into it.
As you can see, I couldn’t catch a break while wrenching this past weekend. But as I like to remind myself, discovering and understanding problems — and devising solutions to them — is one of the hardest but most rewarding aspects of wrenching. It felt like I took 100 steps backward this weekend, but it’s all part of a journey toward bringing these vehicles back to life.
A Jeep 4.0 with a cracked exhaust manifold. What a surprise!
If we’re to believe DT, these motors are the pinnacle of reliability and never have a single problem, so this must be an impossible outlier.
😀
The 4.0 is very odd (to me at least) in that no one seems to think its just OK. People either think its God’s gift to the motoring world or won’t touch it with a 10 foot pole.
Thanks for tossing us the broken Jeep bone, David.
If you use a T-handle on the extractor it takes the shear load off of the bolt which should help
I watched a Youtube video recently about removing exhaust manifold bolts without breaking them. The trick was to carefully work one free, and then retighten it before moving onto the next. Only when they’ve all been cracked loose do you start removing them. If you loosen it – and leave it loose – it makes the next bolt that much harder to remove as the manifold has warped a tiny but critical amount.
Many years ago I was helping a friend change the intake gaskets on a new-to-him SBC and the inside was totally gunked up. I advised him to not mess with it for fear of plugging the filter screen. He took my advice and drove it that way, just changing the oil ever 3000 miles on the dot. Several years later we opened it up again for some other repair and the inside of the engine as immaculately clean. Just regular oil changes with good quality oil gradually cleaned it up.
My dad always swore by filling the crankcase with diesel fuel and idling the engine for 10 minutes or so to flush the engine. I wouldn’t do that personally but he has had good luck with engines over the years.
Done similar, but filled to the brim with diesel, let sit for a couple days, then drain out, so maybe half full. Then fill to full with cheap oil, start and idle for 3-4 minutes.
Drain, replace filter, add new oil with high amounts of detergent, like some of the Supertech blends with some added MMO, or Valvoline Premium Blue Restore, if you got plenty of $$$ and have a local seller of that.
Some really dirty engines would change oil and filter every 1000
That was probably what was in those cans of ‘Motor Flush’ I used to run through my old Ford before changing oil.
That much solid oil in an engine is a really bad sign. I would not run it without at leastflushing it out with kerosene or similar and dropping the pan. That is an oil delivery issue waiting to happen. Depending on where it decides to wedge a piece of sludge, you may lose pressure to a bearing journal but still see oil pressure on the gauge.
I would approach it as systemic if there is that much. Full tear down and rebuild. If he plans to drive it any distance, like South America, then why not.
Gotta admire your tenacity. My misspent wrenching youth salutes you.
This continuing jeep disaster content has really helped me feel less regret about getting rid of my Cherokees. Great when they work, painful to fix when they are broken.
May I suggest a 55 gallon drum filled with 30 gallons of parts cleaner?
If you ever do get her running, I suggest Sister Sludge as an appropriate sobriquet.
When I read in your previous update that you broke an exhaust stud in the head back by the firewall, I thought “you know, if the engine in the parts Jeep seems healthy, it might be worth swapping the engine rather than pulling the head to fix that”. Now that you have found deep evidence of maintenance neglect in the Grail engine, that has become a certainty – get out the cherry picker and do an engine swap. You can swap the flywheel easily enough – that should be the only difference between the 2wd auto engine and the 4×4 manual unit.
And then you had to stop wrenching on order to attend “The Oscars”.
Face it, dude, you grew up without even trying. You’re a modern-BMW-EV-driving, dinner-party-attending, paying-attention-to-girlfriend guy. You’re just a few steps away from registering at Crate & Barrel.
Yes. Long gone are David’s Cracker Barrel days, I’m afraid. Crate & Barrel forever.
Good job David!
If preserving originality is the only thing keeping you from swapping the drivetrain over to the nicer 2wd parts Jeep, ZJ Grand Cherokees are all too common for that. There’s no need to torture yourself over basically nothing.
But he’s not doing it for nothing, he’s doing it for us!!! For clicks!!! For Autopia!!!
I understand but converting a 2wd automatic into a 4×4 manual would be good content too
But David’s refusal to take the easier way out is part of his DNA. Plus the drama of “how will he ever pull this off?!?” adds to the interest of his articles.
On the other hand, it would also be interesting to see him actually make it to Moab in time for EJS.
Here’s the thing. Yes, ZJs are “all too common” but I bet you’ve not seen one like the red Holy Grail. This has manual crank windows, meaning the door panels are ultra rare. Look closer at the pictures of it – it has NO plastic cladding on the bottoms of the doors. There are few ZJs like this Holy Grail. It’s rare (not because it was expensive but because nobody wanted one) and David is the kind of person to whom “authenticity” matters. Is your argument logical? Absolutely. Is this a project where logic wins the day? Absolutely not.
I know. I was around for David’s everything’s a grail period. I enjoyed his enthusiasm but he needs comments like this once in a while to bring him back down to Earth. If he’s allowed to run around freely and unchecked code enforcement usually ends up getting involved.
Well said, my friend. Well said.
These ARE pretty rare, even the auto ones. The uncladded ones were the absolute base model, and that was only available in 93-94, IIRC. The wide black rub strip was there because all the bodies had the studs for the cladding brackets, so that was a low-cost wat of covering them.
David, a grail came up for sale here in the northeast (for a reasonable price)- just buy and fly, stopping at the EJS on the way back.
I think I saw that one on FB the other day! The green one? DT was the first thing I thought of, haha.
You got it
I thought about it for a minute, but as rare as it is I still have no interest in owning one with a manual transmission.
I gave it a hard thought, especially since we are looking for a runabout. But we want smaller hatchback for good mpg. ZJ is not that.
Yeah, every once in a while, I look for a Honda Fit or Mazda 5 type vehicle for that purpose. The Fit’s are fairly expensive, and the Mazdas have a good chance of being rotted out.
That dark orange see-a-kidney-doctor gasoline is exactly what came out of my Comanche that “only sat for a couple years”. My f150 that sat under a tree for 10 years was a little better. That’s kinda just what gas looks like after a vehicle sits outside for 5+ years.
Just knowing I’m not alone makes me feel better about my own multi-year non-running “wonder if the engine will turn over” project….
I can make a guess at what happened to the fuel system – E10, E15 or E85.
What, you think non ethanol fuel wouldn’t have issues after 8 years?
Poke the stalk and you’ll get the husk, pal.
Why.
Why do you keep loving and fighting these utter piles. There isn’t a single Jeep in a long documented history that hasn’t been a pile.
You’re in an abusive codependent relationship with those cars. Time to find a new hobby. Like rehabilitating early 1980s Hondas.
Signed, Harvey Park, MD, PsyD, MFA, MS, BSc, WTF, Phd
Also: isn’t scraping sludge off the head with a screwdriver a risk to gouge the head and compromising the seal?
David ” I’m not addicted, I can stop anytime I want to!” Shaking he reaches for a sniff of Gunk engine cleaner while muttering softly “anytime I want to…”
And that’s when the brakes failed…
You have to try pretty hard to put a significant scratch in an iron head, and even a pretty deep scratch won’t particularly mess up the seal if it’s a skinny scratch. The real problem is if it’s warped or otherwise out of flatness across a large area.
Good to know!
OK, you tore the head off, and see tons a THICK sludge. You’re not sending it out to get it cleans and then rebuilding it?
You could spend several thousand getting it cleaned out and rebuilt, or you could blast it out with brakleen and sleep easy knowing the 4.0 doesn’t care. I think we all know which option David would take.
Personally, in regards to cast iron parts: I blast as much out as possible with whatever is handy, then I spray the thing in oven-cleaner and let it sit for a few hours.
Might eat away at any soft bits, but those need to be changed anyways.
No need; the engine makes great compression. I’m hitting it with degreaser, swapping out the valve stem seals, and shoving it back on with a new gasket.
Save $100, reuse the old gasket.
Yusss hardcore wrenching content is back. I agree with Data – I think you must call upon a higher power here – namely Laurence. Tell Beau to pony up to get him up to LA stat.
Project Cactus was literally a planter and it’s been moving under it’s own power for 1.5 years now. I’ve said it before, import some Aussie power. I find it hard to believe anything would be more daunting than Cactus.
Well look at the bright side… your misfortune will give you more to write about and entertain us all!
Many of us know what happened the last time you took a cylinder head off to extract a broken stud, and then walked away from it. Might as well push it next to the Golden Eagle, wherever you’ve got that stashed. Neither one is apparently ever going to run again.
Please prove me wrong on both counts.
I don’t recommend this and have only done it once but was desperate with no useful tools. I had a stud break off like that once so what I did was extremely dangerous but it worked… took a wire and plugged it in to the neutral connector of an extension cord and ran that to the engine. Another wire went to the hot terminal (the small blade), a 15A inline fuse, and was wrapped around a bolt just smaller than the one I broke off. Held the bolt in place and plugged the extension cord in til the fuse blew. Was able to extract the broken bolt however it wasn’t that rusted in place.
Mad respect for the improvised welder setup. I am equal parts impressed and horrified.
Gas or urine that colour is cause for concern
At least 50% of this is self-inflicted issues to be far, but it be like that.