Clearly, YOU are not understanding that if indeed head warpage is to blame for exhaust valves breaking, then it does not matter how good the exhaust valves are... they will eventually break if not properly aligned on the exhaust valve seats. This would mean by default that an upgrade exhaust valve is NOT a 100% preventative measure!

Do some research on your own without the influence of geordi! He is a guy who has stated that exhaust valves start to become weak and plastic at just above 1200 degrees Fahrenheit, (seriously, exhaust valve steel can take twice that temperature before melting and can withstand temperatures of 1700 degrees Fahrenheit all day). Do you REALLY want to trust that guy's judgement, especially after he continues to promote garbage theories like those he has on about the CRD engine thermostat?

http://www.sbintl.com/tech_library/arti ... onment.pdf

I am quite sure that if you actually did some independent homework on your own rather than rely on the narrative geordi supplies here and on Facebook, you will find that a major cause of exhaust valve breakage in any engine is the cylinder head warping. When you factor in the fact that a diesel engine with an aluminum head is one of the most susceptible types of engines that have cylinder head issues and the likely conclusion becomes quite clear.

You KNOW the CRD engine has a problem with cylinder head integrity... blown gaskets have been an issue for this engine for years and guys like geordi have made serious money running around the country repairing and "upgrading" these engines. Why are you having a problem believing that if a cylinder head warps and causes a head gasket failure that it can also warp metal in the exhaust port area and therefore cause the exhaust valve failures through misalignment? Put 2 and 2 together man! The very place where warpage is going to be the greatest is right around those exhaust ports because of the extreme temperatures they have to endure.

Don't you think that it is at least possible that the valve seats can become misaligned due to warpage and cause the valve to strike one side more than the other, creating side loading and eventually breakage?

Again, you are beating a dead horse! I clearly and fully understand the issue and don't need to do any homework!
I have over 50 years of mechanical experience to draw my conclusions from which include working in a speed shop and automotive machine shop where I rebuilt hundreds of engines and heads. And neither geordi or anyone else has any influence on my thoughts and posts, they are my own and I stand by them!

It makes absolutely NO difference what the cause of a failed valve in this engine, which you nor I or anyone else knows the exact ROOT CAUSE at this point, but the catastrophic damaging outcome of a failed valve is crystal clear!
And we know most reported failures have occurred close to the 200k mileage regardless of age (years) and replacing exhaust valves before this 200k mark is the ONLY option we know for a fact that can help prevent an occurrence. No one to date to my knowledge has ever reported suffering a broken valve soon AFTER replacing their exhaust valves with new ones in the short term.

So one must beg the question, IF valve breakage is due to head warpage or valve seat warpage as you theorize, why do we not ever hear of valves breaking soon after replacing exhaust valves with new ones??? Did new valves suddenly cure a warped head or valve seat, which we all know is not possible. Got to be something else at play here.

While head warpage or valve seat issues may be a contributing factor, we simply DON'T KNOW for sure what the root cause at this point in time. It has never been established!
As I have stated before, I personally think exposure to high heat over time along with stem metal exfoliation due to soot particle blasting by the EGR all contribute to metal fatigue and are the chief contributors to the cause of exhaust valve failure and the Metallurgy Test Report that was performed on failed valves that was published on this forum backs up this in my opinion. And there is also the possibility of a bad batch of valves that was used by the manufacturer that was discussed which would explain why some engines go well beyond the 200k mark and never suffer a valve failure.

Theorize all you want, just keep the discussions civil.

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"So one must beg the question, IF valve breakage is due to head warpage or valve seat warpage as you theorize, why do we not ever hear of valves breaking soon after replacing exhaust valves with new ones??? Did new valves suddenly cure a warped head or valve seat, which we all know is not possible. Got to be something else at play here."

Your answers:

1) .... because valve break over time and use. The side loading is likely quite minute, so it is going to be a lot of miles driven before a failure would occur again.

2) .... if the person replacing exhaust valves is doing the job properly, they will install new valve guides and machine new valve seats to perfectly align the valve with the seat.

I would suggest most having exhaust valves replaced would only replace valve guides if they were worn out & not serviceable. Valves are generally seated & it is clear to the person seating them if there is any misalignment of the seat & guide. I have not seen any reporting of this with these heads. There is plenty of information about warpage of other heads. Its a standard procedure for head rebuilders to lay weld beads down on heads to correct warpage. A thread about head warpage may be of some value. Let's keep such discussion there.
Like most on lost, I am keen to see every possible cause of the failures investigated individually. There is no need to have potential causes competing for importance.

_________________
Australian KJ CRD 2006

It is my understanding based on what most have reported on LOST in the past that valve guide wear is really a non-issue.
Some have reported finding some exhaust valves binding in their respective valve guide which could indicate clearance issues, but not worn out guides issues.

On valve seats, some posters say they simply remove old valves, lap new valves in to old valve seats for a proper seal and install.
I think this may be geordi's prefered method, but he certainly could better explain his thoughts and processes on this more so than me. I cannot speak for others, only speak to what has been posted by members.
A few owners have reported taking their head to a machine shop and having the seats reground to proper dimensions before lapping in the new valves.

Replacing valve seats on an aluminum head is super tricky to say the least, and requires very specialized equipment and knowledge of the process.
Personally I would never recommend replacing the valve guides or valve seats on this aluminum head, it is just way too risky, and aluminum heads are not very forgiving when you start pressing parts in and out of them...
Ask me how I know this,

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The reason why this thread exists is because CRD owners have an unproven notion that the O.E. exhaust valves are inferior due to the number of destroyed exhaust valves reported. I am merely responding that it is likely not the O.E. exhaust valves that are to blame here as there are more likely documented causes for this type of failure. The two seemingly separate issues of exhaust valves and cylinder head warpage are related in this context and therefore deserve to be discussed together.

The purchase of Manley exhaust valves is a good thing because they are an upgrade part made of material that is probably better than the O.E. spec valves. So they should be purchased for that reason only, not on the expectation that it will prevent valve breakage when a more likely reason for breakage exists.

Your quote: "I have not seen any reporting of this with these heads."

If you mean that there has been no reporting of warped heads being the culprit of broken exhaust valves, you would be correct. But that may only be because nobody has looked at a warped cylinder head being a suspect of broken exhaust valves. If you mean that warped heads are not reported I would disagree with you. Warped heads are indeed a problem in the CRD engine; it is the reason why we have an over-occurrence of cylinder head gasket failures.

A misalignment of the valve on the seat is not so readily apparent. We are talking about only a couple of thousands of an inch to be enough for a valve to not strike the seat concentrically and it is unlikely you can feel or see this misalignment. If I recall my engine building class a paste is used to visually see if the valve is striking all the way around the seat at the correct spot. I doubt that most people replacing valves on their CRD engines are going to take this step.

Regarding valve guides, the proper tolerances are extremely tight and it would be inappropriate to not at least check them to see if they are still in spec. If they are out of spec, you can still make them serviceable by knurling the valve guide and reaming the hole back to spec. I would replace them if it was my engine.

The high number of head gasket failures and some head warpage reported on this engine may in fact be due to the OEM "stretch to yield" type factory head bolts that many have reported finding several bolts loose (way below required torque specifications) when they measured the torque on them before removing the head.

A highly unevenly torqued aluminum head going through thousands of cycles of heat up and cool down could certainly greatly contribute to head warpage and an eventual head gasket leakage.

I know some may not be keen on using ARP Head Studs, but they do hold very well and they don't stretch over time like the factory head bolts do. That is why most all racers use them.
And they are pretty much standard replacement on diesel engines in pickup trucks when performing a rebuild or head gasket job. They are even used on many rebuilds of V8 Duramax diesels with their aluminum heads.

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I understand and commiserate with you, WW. Working with aluminum is a pain in the butt sometimes. This is another reason why I suggest that an iron head be developed for the CRD engine. Up front costs would be high, but the CRD engine would last a LOT longer and the servicing of the cylinder head would be easier if it ever requires it, (certainly less than an aluminum head).

Aluminum cylinder heads are sold to the general public as a way to lighten the engine and therefore the vehicle, and also that they are used in racing engines, (Oooooo!) The REAL reason they are used in most passenger vehicles now is because they limit the life of the engine due to thermodynamic problems only partially solved by torque-to-yield bolts. The engine will last typically longer than the warranty, but after that a cylinder head gasket will fail and by that time the owner has had it long enough that he/she just wants to sell it off or trade it in. No REAL commercial or marine engine uses aluminum head/iron block architecture.

If the seats and/or guides are worn out beyond spec, they gotta come out and new ones installed. Take note of the photo earlier on in this thread as posted by thesameguy on January 7, 2020. There are new valve guides in that photo and I am quite certain they were used, so it is not an impossible task. Also to consider... how much can it be for a CRD owner to just get the cylinder head properly rebuilt by an engine builder with all of the right equipment and lots of accumulated experience?

What is the story about not being able to deck the cylinder heads on CRD engines? It was never made clear to me as to why it could not be done.

I agree with you that an unevenly torqued cylinder head would promote cylinder head warpage. This is why it is so important to follow a proper procedure when installing a cylinder head on an engine block. If the O.E. TTY bolts were incorrectly or unevenly torqued from the factory a cylinder head failure would occur soon after the new vehicle owner picked up the vehicle from the dealership. I think it is safe to say that this has never occurred, at least with Liberty CRD vehicles here in North America; however, anyone reading this post who has experienced this should post a reply and inform us otherwise.

The scenario you are trying to illustrate where the loose TTY bolts cause the cylinder head gasket to fail is, however, incorrect. You have it backwards, WWDiesel. The loose TTY bolts do not cause the head to warp; rather, it is the cylinder head warping that causes the TTY bolts to stretch beyond their limits and therefore appear to be loosely torqued.

The reason torque-to-yield bolts fail is because they are deliberately designed to do so when the cylinder head warps in the first place. It is better that the cylinder head warps and the TTY bolts stretch to allow the cylinder head to do this than having the cylinder head crack. A warped head can typically be re-decked and repaired; a cracked head is VERY expensive or impossible to repair. It may also be a case where there is a limit to how many heating/cooling cycles TTY bolts go through before they lose their integrity. In either case, these are problems that can be reasonably measured by engineers and adjusted to give an engine with a limited life span of their choosing in accordance with the manufacturer's wishes for planned obsolescence in an aluminum head/iron block engine.

Trying to get around the TTY bolt problem by using immensely strong studs that will not stretch ever is a case of the cure being worse than the disease. To achieve the strength of ARP head studs, the metal that engineers use and the design they employ for the stud must make strength the ONLY priority; all other desirable features that a fastener MUST have when dealing with the different thermal expansion factors of aluminum and of iron are forsaken. Aluminum has a thermal expansion factor twice that of iron; the bolt clamping the cylinder head to the iron block must be able to allow the aluminum head to properly expand and contract under operation while maintaining a clamping force sufficient enough to contain combustion. TTY bolts do this; ARP head studs do not. Go ahead and use ARP head studs if you are building a competition/race engine; you are likely going to need them in this application. However, if you use ARP head studs in a CRD engine you want to use as a daily driver you will greatly increase your chances of cracking the cylinder head many miles down the road.

ARP head studs were never meant in an aluminum head/iron block application where the goal is longevity. Are they used in aluminum head/iron block racing engines? Most certainly, but the one common theme about racing engines is that they do not last very long. They are designed to get you across the finish line in first place; to achieve this you are stressing racing engines to their limits. Those engines will wear out prematurely and often fail catastrophically. They most certainly do not last long enough for cylinder head warping to become an issue as that would take many thousands of heat/cool cycles to occur, as observed by CRD owners any anyone else driving a stock or lightly modified engine in day-to-day driving.

Finally, I have posted many times on LOSTJEEPS and on the Liberty CRD Facebook page that American Racing Products, (ARP), do NOT recommend using their products on engines that they have not done any R&D on. They have never and will never do any R&D on the CRD engine because it simply is not common enough over here in North America to make financial sense. The example you have given about ARP head studs being used on 6.6L Duramax diesel engines is not valid in this debate. ARP has indeed worked with this engine and has developed at least two different head stud kits for it. One kit is probably for racing applications and the other is probably for people who want a high-quality fastener for their road-going daily driver. To assume that ARP head studs will work well on the CRD engine because they work well on the 6.6L Duramax is conflating the topic.

Call their Technical Support line if you do not believe me; that number is 1-800-826-3045. They would have the same concerns that I have written about here.

Under torqued head bolts at time of head removal for repairs has been reported on this forum in the past by some members.
Do a search.

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Like me. AND I used the ARP head studs. It's the inherent flaw of aluminum heads (which should never be used on diesel engines IMHO). Best thing to do is after assembly, run the engine for a few hundred miles, then retorque the head bolts. Unfortunately for this engine, it's a H U G E PITA!

_________________
GDE FT Ecotune, EHM, Weeks kit stage 1 & 2, Carter 4600 lift pump, Upgraded tranny, Fishing boat hauler!
New at 164K: head gasket, rockers, exhaust valves, ARP head studs, Injectors, 5v Bosch glow plugs, water pump, timing everything, serpentine everything,
New at 225k: new head, timing belt

Did it ever occur to you that the discovery of uneven torqued TTY bolts upon removal of the cylinder head may actually have nothing to do with how they were torqued at assembly time in the factory? These engines are likely assembled by robots, and the torquing of the cylinder head would be precise, both in measurement and how they each would be done exactly the same amount.

The likely reason why TTY bolts have uneven torque upon removal is because those bolts that are easy to remove have been stretched beyond their limits due to the head warping in the first place. The scenario is NOT a situation where the uneven torquing of the TTY bolts at the factory CAUSED the cylinder head gasket failure; rather, it is a head warp, (caused by any number of reasons), that causes the TTY bolts to stretch and lose their holding power, (thereby also losing the torque by which they were tightened down).

Bottom line to those people who support the use of ARP head studs....

American Racing Product does NOT endorse the use of their cylinder head studs on ANY engine they have not done any research and development with. There is nowhere near enough CRD engines in North America for ARP to be bothered with developing a proper set of upgrade head studs.

You can call them if you do not believe me. Their Technical Support number is 1-800-826-3045.

There are also a number of reasons why - outside of ARP not endorsing their products on CRD engines - that CRD owners should be aware of when considering ARP head studs. I could post the reasons here, but WWDiesel may take exception to this.

So,if I may add yet another theory on this thread (which by the way is a great read!).

I, as you know, love these rigs! This is the second one I've owned. I'm a second generation diesel mechanic and love making things better than the engineers intended. All of you have valid points. These engines are mass produced in astounding numbers and manufacturing and engineering flaws are going to happen.

Just for example, on another thread I posted the ARP studs I installed were too long and when tightening down the intake bottomed out and started crushing the cam journals. Apparently the early heads had thicker cam journals. Maybe that's a good thing. Maybe that's a bad thing. Point is,we all thought going into this thing everything is an exact copy with exactly the same capabilities. Nope.

Then I blew a head gasket 60k miles later and find out my ARP head studs on the exhaust side are looser. Big relief I don't have to spend $1,900 for a new head but now I'm trying to figure out how to keep the exhaust bolts/studs from working loose. (When I originally replaced the leaking head gasket 60k ago I also noticed the 4 outside exhaust "bolts came undone easier).

A fix for this for VM Motori would be a simple block/ head/ intake modification to allow the 4 head bolts on the exhaust side access so they can be retorqued after an initial break in and at certain intervals like 30k. Since this can't be done for us current owners without a ridiculous amount of work I am willing to try and experiment. I'm going to be using blue loctite on the threads in the block at the 4 exhaust side studs. I'll run it for 30k then pull the intake to check torque breakaway numbers.

Now for my exhaust valve theory. This, like the former, may or may not have anything to do with the aluminum heads expansion. When I was doing disassembly I noticed the intake cam was not lined up any more. I had to turn it over until I was able to install the intake locator pin then locked the gears together and then loosened the intake cam gear bolt. I then removed the gear lock turned it over until I could install the exhaust cam locator pin and crank locator pin , relocked the gears and loosened the exhaust cam gear bolt. Could this running out of time have affected it enough to cause the head gasket failure? Quite possibly! What could have happened if this occurred on the exhaust cam? Possible valve failure from coming in contact with the piston even ever so gently X number of times per minute?

All this is attributed to the differentiating metals issue. Steel and aluminum have different expansion rates and different heat dissipation rates. Aluminum head on a steel block. An aluminum cam gear bolted ( with no keyway to prevent movement) to a steel cam. Recipe for disaster if you ask me.

I will also be putting blue loctite on the cam gear. Friction fit sounds like it should work but what if your hands were greasy when you touched it? This changes the coefficient of friction. Kinda like putting new CAC hoses on oily intercooler nipples. They can slip off.

I, for one, need to solve this dilemma once and for all!

_________________
GDE FT Ecotune, EHM, Weeks kit stage 1 & 2, Carter 4600 lift pump, Upgraded tranny, Fishing boat hauler!
New at 164K: head gasket, rockers, exhaust valves, ARP head studs, Injectors, 5v Bosch glow plugs, water pump, timing everything, serpentine everything,
New at 225k: new head, timing belt

The level of speculation in this tread is just "out of this world" !!!!!!

This tread is a JOKE !

Without a bonafide "Root Cause" of valve failures, what else is there?
You got answers????

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