Jeep 4.0L Runs like "Garbage"? (Part 2 - WEIRD Engine Problem & Repairs)

Customer approved removal of the HEAVY cast iron cylinder head on this 2001 Jeep Wrangler 4.0L to replace the leaky EXHAUST valves on cylinders 3 and 4.
However, after head removal, it becomes clear that the valves are actually fine!!
However the valve SEATS are severely RECESSED into the head!! WHAT??
Does it need a whole new cylinder HEAD?
The local machine shop didn't seem too surprised at this finding and said they could refurbish the existing head by installing hardened exhaust valve seats no problem.
Will this Jeep get back to full health with the "bulletproofed" cylinder head?
Milwaukee 2457-20 M12 Cordless 3/8" Sub-Compact 35 ft-Lbs 250 RPM Ratchet:
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Lisle 36050 Valve Keeper Remover and Installer Kit: **$40 OFF!!**
www.amazon.com/dp/B0012S61IO?...
OTC LEAK TAMER SMOKE MACHINE:
www.amazon.com/dp/B007X74ZTK?...
Enjoy!
Ivan

[@jamespn]

378K on a wrangler, my back hurts just thinking someone rode in that Jeep for all those miles.

[@wernerdanler2742]

Have you ever ridden in the back of one? You need a surgeon after that. 😂😅😂😅😂

[@jamespn]

@@wernerdanler2742 After riding in a Jeep Wrangler, an 87 Plymouth Horizon rides like a Lincoln.

[@adotintheshark4848]

Don't tell your back about a Smart Car's ride.

[@Mag_Aoidh]

I have a 2.5in RC lift and I popped my neck the other day just driving over a bump on one side.

[@IsItTrueThat]

Thanks for sharing the unintended acceleration on the first start up. It makes your channel real because you show and talk about the bumps in the process. Really felt for you having to undo so much to refit the intake properly. Love your upbeat attitude.

[@wallebo]

Same here.

[@LeverPhile]

Look at the bright side ... the second time is usually easier and faster.

[@ThunderbirdRocket]

Yeah ! Amazing !

[@petepeabody8905]

When the lower end finally goes and it's belly up at the local scrap yard someone is going to find gold with that newer cylinder head. Thank you Ivan

[@_RiseAgainst]

I found a freshly refurbished seat for my S-10 in a junk yard. Someone took the time to cut, fix, and reshape the seat foam (bucket seat). And the center console was refurbished as the top always breaks in. Funny thing is, it didn't match the rest of the blazer I found it in. So I presume the seat was pulled from the scrap yard more than once.

[@robertsmith2956]

I pulled a rear axle at junk yard, and damned if it didn't have brand new brakes. springs, calipers, pads, all brand new never used. Same couldn't be said for the wheel bearing, 2 months later had to replace it. Glad I didn't give them back the old axle, puled the shaft from it, and put in new bearings.

[@Ilovetittiesandbeer]

I love a good straight-six engine. They are usually easy to work on and last forever.

[@user-ee1ki5lz5e]

where does one find morons as such who put thousands of dollars into repairs every few years until the next thing breaks, butta for mechanics

[@nogarage_ou812]

That used to be a common problem for leaded fuel engines when they switched to unleaded in the 70's. The fix was to put in hardened exhaust seats just like you had done.

[@jfv65]

Also for engines that had been converted to LPG. Specially when the engine has a cast iron head with the valveseats cut directly into the casting. #microwelding

[@MattyEngland]

Yeah, valve seat recession.

[@theblackhand6485]

The seventies are a while behind us. This car already had hardened seats! There were probable two valve seats missing. You might wonder how that happened. If there were seat then the earlier machine shop didn't do its work well and grinded just to much off of them. But just mentioned, the seat were probably missing.

[@1deadeye]

Jeep guy here. The 2000-01 331 heads are well documented to cracking between number 3 and 4 cylinders. They're called non tupy heads. When casted. There wasn't enough nickle used in the casting making them soft. The excessive heat created by the 3-4 exhaust valves next to each other is its demise.

[@arthurfricchione8119]

Sounds like crap Ivan . Well it’s a jeep.

[@PineHollowAutoDiagnostics]

Good thing this particular head was TUPY 2002 or later 😊

[@zf9903]

@@arthurfricchione8119”Jeep issues” is code for CHRYSLER issues. The very first thing Chrysler did when they bought AMC was to cheapen the then-new 4.0. The so-called “H.O.” 4.0 simply had its power band pushed up, and lost several key features such as the knock sensor. Early 4.0’s, ones that weren’t cheapened by Chryslers, are better engines. Later 4.0’s are alright, still good by most standards, but the TUPY debacle is a huge wart on their legacy. Again, it’s all Chrysler.

[@mmocken]

Note, the back to back 3 and 4 exhaust valves get hotter than other cylinders and typically do soften the seats and receed,. Also,.low collant pressure can increase engine temp and might have contributed to failure

[@stevebot]

I’m with you there, unpressurized and hot spots around center cylinders. IIRC some years those heads also develop cracks in the area of the center cylinders, likely due to temperature issues.

[@LeverPhile]

Makes sense ... two exhaust valves side by side with no intake air in between to cool them.

[@user-wu8pb5tk8s]

Caused by just flame hardened head valve seat and running unleaded fuel, not having hardened inserts.

[@shakey2634]

When I used to do my own maintenance on cars built in the ‘60’s, it was a common joke among my friends that when you fixed one problem you found that what you fixed masked one or more other problems. Most problems were mechanical. The only electrical tools needed was a test light a timing light and a dwell meter.😊

[@robertsmith2956]

In 2000 I picked up a '71 f100. Hey I still have a dwell meter. Now how do I hook it up?????? Sadly the electronic ignition conversion companies are all gone now.

[@retro440]

On GMs, you didn't even need a dwell meter!! Just turn the points adjustment screw on the side of the distributor in until the engine started to miss, then back it out a turn. Ah, for the good old days!!

[@gwrider2146]

shakey2634 Yeah, this is the reason I normally won't do a partial repair on an old high mile engine if it's getting torn apart like what was done here. Yes, it's "cheaper" at the moment to just do the head, but chances are there are other problems in the bottom end (or shortblock) that will then make their appearance once the worst problem is fixed and so if the teardown has to happen again in a short time, this adds onto the cost of labor and gaskets, fluids, etc of doing alot of it twice instead of just once. Rebuild it all or replace, no partial fixes.

[@BigEightiesNewWave]

Here is some more info. Chrysler certified mechanic who owns the shop that was trying to get a handle on a problem with misfire for me. This gent is a former Chrysler engine tech in the Cherokee plant, and pretty much knows the 4.0 inside and out. My problem was a bit baffling, so he went searching for answers. Even his $20K diagnostic computer was at a loss to locate my miss. The miss was enough to tell the computer to unlock the converter due to loss of engine power. Same sunken valves you have was culprit. Also check the casting numbers, there is this...#0331 (1999-2006,) reduced the exhaust ports a bit more, modified the intake slightly, and the earlier ones (1999 to mid-2001) are the "#0331 Club" or "#0331 Card" heads that crack. The later (mid-2001 to 2006) heads with the TUPY foundry mark are revised to address this, although there was no official acknowledgement and no recall issued.

[@CraneofBoulogne]

Some knuckle head with a valve seat grinder cut those seats deep into the cast iron, maybe to avoid repairing the head properly, or replacing it altogether. Those seats did not wear down that low on their own, not in a million miles.

[@thomasjensen5237]

When valve seats are induction hardened at factory ,the process is only so deep. After several valve jobs it's very common to grind thru the hardened cast iron and have this recession occur. Especially on center seats that see more heat. I used to build 4.o and 2.5 engines specifically for postal vehicles by the hundreds literally. The induction process is only so deep and head should've had seats put in on last build.

[@NoPlanProjects]

Bingo!

[@marty0715yt]

Boy the u joints were preparing to leave premises soon. Maybe before the rod comes thru the block.

[@clintprice2123]

Nice to know that when there is a hiccup during a repair it is not edited out. It’s used a a teaching moment and corrected. Ivan once again gets it all figured out and a happy customer goes down the road!

[@alansoccer2003]

Imo that's not a knock. That's the 4 liter piston slap

[@v12alpine]

yup, one of mine sounds like a desiel as it warms up. had been doing it for years.

[@rodneymiddleton9624]

I have rebuilt several of those engines and some of them were prone to piston skirt, breaking which causes a knocking weird sound in the engine. Thanks Ivan!

[@aaronkoivu]

This engine are famous for exhaust manifolds cracked causing o2 sensor codes, was thinking this would be a problem after the cylinder head replacement, part 3 lol

[@jerryking2418]

Praise the machine shop for refurbishing the head and valve seats and valves. Interesting case study.

[@rhkips]

Nom nom nom valve seat~ I honestly couldn't tell what I was looking at, if the original cast iron seat was worn down, or if it had been rebuilt and the shop that put seats in originally overshot the depth, or used a cheap seat. Either way, this was a great set of videos! My personal experience with these engines has not been good, but I know a lot of people swear by them, so I gotta acknowlege my personal bias. There's something to be said for the simplicity of these engines!

[@fpoastro]

You need a proper bench so you can get up off the floor 😊

[@davebigdog]

Ivan wears sandals when the weather is nice I don't think he's going to get a proper bench 😂

[@Peter_Riis_DK]

@@davebigdog Safety shoes, russian style. 😎

[@davebigdog]

@@Peter_Riis_DK 😆😆😆😆😆🤣🤣🤣

[@JRS-iq9pz]

I agree. That's hard on your back working on the floor.

[@lvsqcsl]

@@davebigdog Yeah and when it gets hot or he needs to get serious about something his shirt comes off.

[@autotek7930]

That knock is piston slap, they have an updated design piston that won't prematurely wear out the piston skirt, that's what killed my old xj engine..... now it lives with a 4.7l stroker engine in it

[@theblackhand6485]

Yeah piston slap. To late know. May be the slap can partially be helped by tuning the engine with a thicker oil and an ceramic- of PTFA/PFAS based additive (?).

[@udrtydog1]

Not being able to hear the "knock," in person, I would say the same thing.. piston slap! Those straight 6's were notorious for that! #PHAD 🇺🇲

[@Dave-ei7kk]

Worn/loose bearing at the top end of a crank rod can would that way too.

[@sheerwillsurvival2064]

A machine shop like that is priceless 👍🏻

[@topher8634]

Only concern i would have about a cylinder head rework with new valves that seal is now you have great compression that is going to put increased pressure on a worn bottom end. I had a mishap on a Tahoe with over 300K. It had a burned exhaust valve on driver's bank. I sold the valve job without even thinking about increasing the pressure on the rods. It ran great for 10K then a rod knock developed and became more and more pronounced until customer no longer trusted it. Of course i was blamed for the failure and ended up swapping in a junkyard assembly for half-price just to satisfy him. After that incident, I made sure customer was aware with a signed statement before hand.

[@terrymax5340]

You can replace the rod bearings . Dropped the pan on many and replaced rod bearings . Bearings are cheep with a pan gasket .

[@Frost640]

Rear main is a 2 piece, do that while the pan is off as well.

[@sebastiaanfellinga4413]

Thanks Ivan , have a nice sunday

[@autotek7930]

Good morning ya'll. Now i wanna see you diagnose death wobble lol. Your approach would be watched by millions!

[@jacksautorepair]

On Dodge and Jeeps with a straight axle frontend, could be the track bar wore out. Some lift kits require an adjustable track bar, which is often overlooked. Inspect frontend or steering and rotate tires first.

[@autotek7930]

@jacksautorepair we all know all this , I just wanna see Ivan tackle it, sometimes it's not obvious as in a loose part

[@jackhandyy]

​@@autotek7930he would figure it out in 3 minutes, if not less...

[@MattyEngland]

It thought 'Death wobble' was Joe Biden trying to negotiate a set of stairs 😂

[@autotek7930]

@MattyEngland same concept but this one is on a jeep or solid axle 4x4🤣

[@karenkartz3163]

Yes many times the seats are crap in 4.0 and common cheep fix was to ream valve guides and cast seats which come apart bigger oversize valves.Back yard stuff.

[@milesmahan]

Well done weedhopper~! Carry on... Didn't appreciate you making my back hurt thru osmosis , been there 😊

[@volvo09]

Good point on not replacing a bad radiator cap on a vehicle with tons of miles. There iasn't been pressure in the system, and it has been through thousands of heat cycles.... You don't want to suddenly pressurize it! At the least you can randomly lose a hose, or worse radiator / heater core....

[@mph5896]

Eh, I personally could not send it out with a leaky cap.

[@truracer20]

The cooling system is THE reason this happened. Pressure raises the boiling point of the coolant. Boiling causes steam. Steam raises the temperature in the area which it occurs.The extra temperature and lack of cooling effectively anneals the hardening of the valve seat, it SOFTENS the seat, and this is the result. Would you rather ruin the entire engine or replace a a heater core, radiator, hoses etc. Telling a customer to NOT replace the radiator pressure cap IS a stupid move.

[@LeverPhile]

@@truracer20 OK, fair point ... and especially after seeing the exhaust valves on cylinders 3 & 4 are right next to each other. Changed my mind from my prior post.

[@KStewart-th4sk]

@@truracer20 He DIDN'T tell her to not replace it like YOU claim. Maybe he could have told her the consequences of not changing it, BUT there are lots of litigants on these Court TV shows filing claims against mechanics for crap they have no control over. I can hear one now: "Judge my heater core wasn't leaking when i took my car to him, now it is, and he should have to pay for the new core and the cost to install it". I'd like to see your Channel, where you fix the problems Ivan comes across, instead of the smart-ass putdown.

[@Sandmansa]

There is a reason why cooling systems need to hold some pressure. The 13-psi worth of pressure the cooling system is designed to hold, will raise the boiling point of water slightly and help reduce the chance of flash evaporation. It will also help pinpoint any coolant leaks that will eventually develop. Allowing air to enter the cooling system will cause the engine to develop hot spots and overheat. Catastrophic damage will soon follow. Take this case as an example. I know my explanation sounds a little overly dramatic. But so can getting the news that someone needs to have an engine rebuilt or replaced, that could very well have been prevented with a $15 part. Now that's out of the way, awesome diag and a glorious repair Ivan! I love how you left in the oops part when reinstalling the intake. A lot of us have made that mistake at least once. The best part is when you explained how it happened. So the next adventurous soul that watches this video and tries to do this job for the first time, knows what to look out for. You're not just a great mechanic, but a good teacher too Ivan. Thanks for sharing.

[@DonDegidio]

Hi Ivan, Never seen valves that were that low in the head, and they did look to be machined at that depth. Kudos on the repairs and finding the other problems for the customer.

[@RK-kn1ud]

Wrenching on cars sucks...just when think you have every tool, they come up with a new type of fastener! 12pt bolts/studs are commonly used in tight clearance situations because they are physically smaller than 6pt. It would behoove you to have full sets of deep/shallow and SAE/Metric for engine/driveline work.

[@BigEightiesNewWave]

JeepForum...nailed it! 537 posts · Joined 2008 #7 · Oct 15, 2018 AFAIK no stock 4.0 head has seat inserts from the factory. It is only going to have inserts if he takes it to a machine shop and has it machined to accept them. So the existing valve recession is a non-issue in terms of the head being able to hold new seats, since it has yet to be machined for them in the first place. Apparently Jeep cut the valve seats directly into the iron casting then induction hardened them, no hardened steel seats were used during the original manufacturing. Flame-softened metal, via Chrysler.

[@theblackhand6485]

Wow! That is so un pro from Jeep!!

[@ThunderbirdRocket]

Extraordinary detail ! Super helpful ! I learned lots !! Thanks mate 👊🏼 🔥

[@farmermiyagi1338]

Ha! I had a Ram in here a couple weeks ago and they had swapped out the headlamp bulbs with LED bulbs. Those LED bulbs can be installed upside down and cause the headlights to be opposite of what they should be. I was doing the same thing: hitting the dimmer and they were backward.

[@pedroequis9396]

Cylinders 3 and 4 exhaust sit next to each other thus more heat in that area. That area is more prone to problems such as cracks, gaskets and burns

[@GNX157]

28:45 That brings clarity to everything with this Jeep.

[@ChrisWilliams-pu8pj]

Ivan, I love the way you show the good, the bad and the ugly. I'll bet there are few that do a real "live" start like you do. Great advice on the radiator cap replacement as well. Cover your bases. Thank you for a great video series.

[@944play]

Hard to believe anyone was making a reverse flow head in the OBDII era...

[@LZDEN]

great work Ivan, a job well done.

[@dustcommander100]

I'd heard about unleaded gas and unhardened seats causing this, but had no idea what it looked like. Didn't think about it much until I bought an antique car. Leaves me wondering if soft seats are still around, and whether that head was rebuilt and 2 soft seats were inadvertently picked up. Or whether new seats were installed and the seat supplier had a couple soft ones mixed in with the correct ones they supplied to the rebuilder. Anyways, it certainly made for an interesting problem! Because I suspect my engine has never been apart (low compression across the board), I use a lead substitute when putting in fuel. Great video!

[@THEDRAGONBOOSTER8]

Great video,very interesting. Also like to say ,well edited..

[@johnz8210]

I did that with the intake manifold once, just off the pins slightly, but noticed it wasn't on correctly before it got too far. I saw a gap looking through the space where the p/s pump goes. The lower manifold bolts are like reading Braille. The Jeep was quieter before - so it probably is piston slap. Now that it has compression it's louder.

[@gpranis]

This type of exhaust seat wear was very common back when lead was removed from the fuel in the 1970's. Manufacturers instead of putting hard seats in, would induction harden the cast iron at the valve seat to save cost. This hard area was only .015 to .035 deep, so if a valve job is done many times all of the hard seat is machined away. The reason #3 & #4 are worse than the rest is because these exhaust valves are right next to each other and as such the hottest point in the cylinder head layout. More = more wear.

[@gpranis]

Also worth noting that most truck heads since then are equipped with seat inserts for durability.

[@franks5553]

You got that machined head back in two weeks, very impressive!

[@somerandomguy3868]

Certainly better than it was, it's a shame the owner didn't give you more information before starting this project, still nicely done

[@fredautos]

That's great.. happy Customer, Great fix... And satisfied viewer!

[@6996brandyl]

It's amazing , I notice the gas gage up up after sitting for 2 weeks Never seen that before

[@user-ll4wj2fm6h]

Good machine work,yes seen before. Good work 😎

[@falcon8553]

Hello Ivan. When one works on something and you say it is done, there is sense of relief and confident in your work, but a little nagging feeling of what if it does not work. And it does not. I feel like someone hit me in put of my stomach. 😢. Awesome work.

[@falcon8553]

I hate auto correct. Put, really when I know I wrote pit. 😂

[@BigEightiesNewWave]

Also, there is this...Originally Posted by Radi Yes. AMC started induction hardening the valve seats in it's I-6's in 1972. Chrysler did not design the 4.0 head, nor did they make any valve seat decisions. That was done by AMC in Kenosha years before Chrysler took over. Chrysler made a few relatively minor head changes over the years including the infamous 0331 emissions redesign, but did not do away with the induction hardening. Heck, they ran the original AMC tooling until it finally wore out in '96 or '97.

[@jimpetty2961]

k-town

[@LeverPhile]

Ke-nOH-shah

[@adotintheshark4848]

the 4.0 liter takes its heritage from the 232 and 258 inline AMC sixes, both excellent motors as well. They powered the Rambler, Gremlin and Hornet especially, for years. The rest of the cars may fall apart, but the motors kept going!

[@user-sb9vw4ys1z]

Just for fun I owned an 1980 jeep Cherokee when I bought it it had 72000 miles on it I put a plow on it and plowed with it till I had 214000 miles on it and never had any problems it ran like a new truck and never used a drop of oil I got rid of it because I was tired of shifting it had a 258 in-line six and it is a strong bullit proof engine and just maintain it and it will run for ever

[@andyayres8613]

As some one else said. It’s valve seat regression. Unleaded fuel in a leased head. The only way is to fit hardened valve seats. Was really common in the uk in the 80s and 90s

[@johnclamshellsp1969]

Good morning Ivan, always great videos. FYI, my 1999 Chevy Tahoe, has had a 10min cold AM knock for 15 years now with 60psi oil pressure. That engine also has great oil pressure, I suspect something else other than rods or mains. I highly suspect a piston slap issue.

[@focus82grothm.84]

The cylinder head turned out lovely 😊 and a great video as always Ivan 😊👍

[@baxrok2.]

Great job Ivan. Thanks!

[@brianw8963]

Happy customer, what else matters. Guessing there might be some skirt pieces in the oil pan. Nice fix Ivan. 👍👍🇺🇸. And I will definitely keep that machine shop in mind.

[@Guillotines_For_Globalists]

Could always do a little tappity tap tap and roll some new rod bearings in there, hope and pray the crank bearings aren't as far gone.

[@nickpogoler]

Ivan, thanks for all you do. I would refer you to the latest Savvy Aviation webinar here on KZbin for a detailed explanation of what valve seat recession is and why it occurs. It’s fascinating to me that a car built in 2001 doesn’t have hardened seats, since it was a well documented phenomena as soon as unleaded fuel hit the market in the 70s.

[@cullenmiller8170]

Nice video and conclusion. It looks like it still has many more things that could be fixed down the road. You’re lucky that you still have a machine shop in your area. Those are hard to come by these days.

[@peterneal7160]

I've done quite a few of these usually in Cherokees! Never had a problem with the Manifolds before! The OLD style Header type Exhaust Manifolds would always crack in a few places! Had a few Cast ones also crack!

[@mikechiodetti4482]

Nice job Ivan! Let's see. Front axle "U" joints, reman short block, (possible) front suspension parts, for now. More later. It is a 4.0L in line 6 which is one of the best engines that the Jeeps had. My wife had one in a 1997 Jeep Cherokee. I replaced the old exhaust cast iron manifold and the front 02 sensor. Other than that, GREAT ENGINE! I once had a 1977 Datsun 200SX that had the L20B engine. 2 intake valves sunk in the aluminum head. The machine shop put in 4 new intake seats and I had to get 1 new valve for it. Problem solved.

[@lvsqcsl]

I am wanting to say that in the early 1970's Ford went to hardened valve seats in anticipation of unleaded fuel. I have been told not to use anything but 5W-30 in the 'ol Marquis even though it has 500,000 miles; and it has an aluminum cylinder head with OHC. I don't think I have seen that much smoke since I saw Ozzy Osbourne in concert in 1984. I was thinking AMC engines contained more nickle than other brands at least in the engine block; yes, this was made well after 1987 when Chrysler bought out AMC. GREAT VIDEO!

[@walkingwithdogs8547]

You can never have enough tools in your tool box, it's a life long thing building it and never stops.😊

[@farmermiyagi1338]

Yep, someone has been here before. Stock heads have seats as part of the head. If this has steel valve seats, it was done by a machine shop.

[@BigEightiesNewWave]

LOL looks like the rebuilder did not put in valve seats. So essentially, made it worse.

[@farmermiyagi1338]

@@BigEightiesNewWave I would have to agree seeing as there was absolutely no damage to the head or piston. A dropped or broken seat would surely have left evidence. ;)

[@MattyEngland]

​@@farmermiyagi1338Probably gone out the exhaust. No turbo on this so wouldn't have really be noticed.

[@tsxownz]

i wish you had shown the cylinder head bottom as a before and after

[@mistsmogguru8378]

You'll find them in the exhaust. I have encountered this on cast heads.

[@richard1835]

thank you PHAD

[@YourNeighborhood_Mechanic]

Rod knock and wrist pin knock have that distinct sound. Refurbished head seals topend , increase combustion pressure will wipe that bottom end out in 6 months if it's a daily. You have done a great job , most repair companies would not have done it due to the miles. They would have sold a new motor.

[@andrewbaruth2318]

Excellent diagnosis. The customer was spot on getting that Jeep fixed. I hope they get many years of good service with it. Watched a video by Eric O. working on a Buick Enclave or something like that. He had to remove the windshield wipers to replace the left front wheel speed sensor. WTF!

[@GreyRockOne]

Nice work Ivan! Only thing I'd have done extra is clean that dirty battery terminal, Thank You Sir!

[@davidthomits544]

Looks like Jeep life always need a ton of work never stops i know I work for a guy on the side who owns Cherokee and wrangler told him put a road flare under the seat

[@rodx5571]

Hey, at least you missed the dowells on the intake and not the cylinder head. Every working tech has done it in one way or another.

[@michelbrown1060]

Haaa the legendary smoothness of the inline 6. . ☺

[@slomotrainwreck]

Had a 2003 Wrangler Rubicon (TJ), bought it brand new. It had front axle shaft seal leaks and an auto trans cooler line leak at the quick coupler at the trans that left me stranded, all happened within a year of owning it, oh, and the hardtop leaks like a sieve, the dealership could never fix that issue. Driven on the streets with just a bit of freezing rain that short wheelbase that shines on the trails will try to kill you. On long highway trips I tried some hypermiling techniques and even drafting behind a big semi trailer rig, the best mileage I ever got with that straight six was 19 MPG and that's doing 65 MPH the whole way. I was at the RAM/Jeep dealership recently for an oil change and they had in the showroom a beautiful metallic purple 4 door Wrangler Rubicon 4xe for $79,000, how things have changed...

[@itsdavex2]

I worked in a machine shop for 8 years, did my fair share of valve seats and guides. You would see them beat like that once in a while. Nice diag in part 1 and the shop did a nice job. Also saw the intake thing once on a 4.0. Same thing wasn't quite square on the dowels.

[@jtjones4727]

Wow head looks nice. There is a pretty good machine shop in Birmingham, AL that I've been dealing with for years. They are my go to shop for cylinder head work. It's awesome to see the transformation when a master machinist takes an old head and makes it better than it was when it was new.

[@theblackhand6485]

A'LA BAMA, well boy ride 'm home!

[@user-wu8pb5tk8s]

You asked to comment if we'd seen such valve seat recession before. I commented as below in your part 1; Retired now but it was common to see exhaust valves receded that far or further on cast iron heads running on LPG (common after fit in taxis in the 80s and 90s here in Australia) in the days of leaded fuel. LPG has no lead, hence valve seat recession caused by "welding" of the valve face to the head with no lead to intervene. Over time the seat material goes out the exhaust pipe and the valve becomes recessed. The ticking that goes with it is the valve clearance in the "lash" of hydraulic followers running out of clearance. Usual cure was to put inkonel or other hardened valve seats in the head and stainless or inkonel valves in. Since introduction of unleaded fuel and aluminium head the seats are induction hardened or in aluminium heads, hardened inserts. Those valve faces you took out also looked to be too wide, part of the process. I "donated" a head off a Chrysler Valiant in much worse condition to the local Technical College (apprentice training school) as an example.

[@user-wu8pb5tk8s]

Also, time for another machine shop, Ivan. He failed to face the manifold face of the head and it looks pretty crappy.

[@mariosaccoccio1688]

Wow. This head was definitely rebuilt before, just not done right.

[@franksprecisionguesswork501]

I think the Jeep looks to be in pretty good shape, except for that worn universals. I think I’d start looking for a rebuildable short block. Then get that rebuilt and ready to go in when you can’t hear the radio anymore because of the rod knock. I know most people say it would be crazy to be putting money into it. 24 year old jeep., but I can bet you would be way less than the cost of a new one and it last much longer. Speaking from experience here I have a 1967 Kaiser m715 Jeep that I rebuilt 8 years ago.

[@daveerrington5166]

Well done sir

[@saiautomotivemilton.7128]

Great video.

[@frugalprepper]

Bringing up the compression on that old of and engine with a nice new cylinder head..... Will need a new bottom end in about 5k miles or so. That has been my experience. Great Video Ivan.

[@mph5896]

Yup. It could be burning oil like crazy with the top end nice and tight

[@BigEightiesNewWave]

The rebuilder ran out of valve seats, this is awful. In 2013, I bought a 1990 RENIX version of the 4.0, drove it a lot for 3 years, sold it at 260k miles, still ran great. All it needed was a new combo MAP/TCU sensor, and an EGR solenoid, which Jeep dealer still had for my at the time 24 years old Jeep. 1991 H.0. Chrysler did all the electronics, made more power, and did not need an EGR. RENIX is Renault/Bendix Also, on my 1990, there is not really a PCV valve per se. It is just a metal tube that gets progressively smaller towards the end LOL

[@SHSPVR]

That's not true I did a 1988 with 258 (4.2) and it did have an EGR system just like 1990 model year did but 1991 was the introduction of the first 4.0 liter in Wrangler which did have more power. Oh 1990 did have PCV Valve it was build in to front elbow unless someone change it with the wrong part.

[@zf9903]

@@SHSPVR”more power” is extremely simplistic. The “high output” 4.0 did have higher peaks, but it had less low end and was generally less efficient in most driving situations as a result. It’s not a worthy tradeoff unless you drive around at 5k rpm all day.

[@adotintheshark4848]

This is like a trip down memory lane for me. On Chrysler slant sixes and Chevy 235's (both of which I've done) I just undid both intake and exhaust manifolds and slid them out of the way, never took them out of the car! They're a piece of cake to work on too. About that knocking, I wouldn't worry until the oil pressure starts to drop. Right now it looks good!

[@curtisgore1611]

You done your job. But that's gotta hurt to hear that knock after all that work.

[@glenharper3136]

Thanks for the video Ivan.

[@PineHollowAutoDiagnostics]

My pleasure!

[@1954307]

great job ivan i just love these more detailed vids...

[@boogerhead0]

Some years ago, when I did work in my prior home garage, I needed to offload a 14x40 lathe from pickup bed. I screwed two C-channel irons back to back to ceiling, through sheetrock, lagscrews into the 16" OC joists. I then made a pretty good trolley using sliding glass door wheels, to fit that ersatz I-beam, placed stop screws each end, and hung a 2ton chain hoist to the trolley. Then I placed a vertical 2x4 crip each end, on L-hook to add additional support, these crips just touching the floor. The lathe, crate, and stand all came out just fine, and years later, used it all over to outload the lathe and everything else in my garage shop, moving to a real shop. That beam was also moved to new shop, which has overhead doors, so somewhat interferes with the usage of the beam/trolley, however, I can load heavies onto a trailer, with door down, somewhat. But that trolley did prove very useful in working on various machines, and light loads like that head would not require the vertical crips, which just hang out in the corner, out of the way, if there is such a place.

[@robertsmith2956]

I put a couple of 4x4's across the rafters, and used a winch. Pull engine up, roll car out of the way, lower engine to ground.

[@aaronkoivu]

3.0L Chrysler/Mitsu in the caravan had this problem with valve seat and valve guides dropping

[@davidturner4639]

Good video Ivan. Happy that you found a machine shop, they are disappearing. I now have a 3 hour drive to the closet one where there were several within minutes 10 years ago. I really wonder if the valve seats were removed and never replaced by the last "machine shop" that called it good enough to dump it on someone else. They may not have had the equipment to cut the seats and fit new ones.

[@RussellBooth1977]

Yes,I mentioned before that the 3.8 litre Buick L36 V6 engine in my dads Holden VX Commodore had that problem with exhaust valve seat recession due to the use of LP gas which is very hard on the exhaust valve seats in the cylinder head. In Australia the locally built 3.9 & 4 litre Ford inline sixes suffered from that problem in the Ford Falcons when they were used as taxis because they ran on LP gas. The later DOHC variant of the 4 litre inline six was released in LP gas form from the factory by Ford Australia for LP gas use,Holden had a version of the 3.6 litre V6 LE0 engine which was an LP gas only engine in the VE Commodore but not as many of them were used as taxis as the Ford Falcons, perhaps Ford offered a bigger fleet discount to the taxi industry than what Holden did in Australia. My youngest brother also dropped an exhaust valve in his EJ20J powered Subaru Forester & my cousins husband whose a Subaru trained technician got the cylinder heads rebuilt using new valve guides,new valves,new exhaust valve seats, & new valve springs at a cost of $3500 AUD which was more than the car was worth. My brother kept running it on LP gas despite my cousins partner telling him not to !

[@user-ee1ki5lz5e]

longer comments next time mate

[@JohnDoesGarage]

Now that the valves are sealing perfectly on an engine with some miles on it they might see it start leaking oil due to the increased blow-by of the rings. I've seen that happen, but you did what they wanted done. I might just let them know there is a possibility it might start leaking oil and it's not your fault.

[@Dave-ei7kk]

There were two low compression cylinders. But they were the ones with the missing valve seats. If they all had good compression after the head rebuild then I don’t think oil consumption will be a big problem.

[@Bill-wz6tw]

You can replace the valve guides and seats on these heads or you can just order a whole reconditioned head already done and ready to install.

[@personalimpressions4749]

You should mount a winch to your floor, to pull bricks in. Can steer and use a remote 😊. Great work and video.

[@GeminiSeven43]

Great video Ivan you have the patience of a Saint. One bad thing about cylinder head work (Besides the back-ache) is that by restoring cylinder pressure now you can see the bottom end problems better (Kinda like the radiator cap fix...LOL) Hopefully the jeep will have some happy miles before the inevitable. Take care Buddy!!!!

[@beezlebub3955]

I had a few F150’s with the 300, those interlaced manifolds are such a pain going back together

[@jimburgess9205]

It’s alive!

[@dannytall8699]

Love the Jeep, seen a few of them across the pond here in the UK, pure Americana.

[@gianfrancoa]

Ivan must be really lucky. Normally machine shops and two weeks can't go on the same sentence 😂😂😂😂😂

[@randyhughes5160]

In the 70s there was lead in the fuel it was lubricant for the valves when they went to unleaded you just added lead additive to keep the valves from beating out the seats

[@davidgrisco1939]

It's not "garbage." Say it like a French man, "gar-bage." 😂

[@BigEightiesNewWave]

Rubbish is high-end garbage 😂

[@fredmalito9869]

I’m willing to bet that the reason that head had been removed previously is because of the known issue with certain casting number heads cracking. I don’t remember what the markings are that are visible when the oil cap is removed, but it’s easily googled. They were notorious! I think that with that head was coming off, and the amount of mileage, were I the customer I would have elected to have the oil pan dropped, pistons pushed out and re-ringed if the cylinder walls did not have any excessive wear, and new bearings installed on that bottom end. I’ve got a 2000 Wrangler myself, only has 91,000 miles. I have the utmost confidence in its powertrain as we took a 1988 Cherokee to about 300,000 miles before selling it. The only thing that was ever done internally was rolling in new bearings when we had an oil pan gasket replaced around 200,000 miles. Those engines are probably in the top 10 best engines ever put into a noncommercial application, and if maintained, I would expect them to go 400,000 miles with little no problem. Now, the rest vehicle? Well, that’s a different story.

[@user-rr7ns4ht3r]

I have seen sunken seats like that before, but they were all in very high mileage vehicles and/or engines that had been ran really hard.

[@wagoosh78]

tht motor was worked on before it got to you looked the head seat was either made tht way or redone tht way . but you did the customer right sending to a machine shop