This is wrong, just flat out wrong, and I believe the core of your misunderstanding. TTY bolts are designed to be installed within their elastic range. When mis-installed they can be stretched into plastic, and over time, with abuse, they may also achieve that state. But the *entire point* of using TTY bolts in mixed-materials engines is such that they are installed in their elastic range and thus *ideally* suited for mixed materials engines.

https://www.counterman.com/torque-to-yi ... -replaced/



https://www.felpro.com/technical/tecblo ... bolts.html



https://www.boltscience.com/pages/faq.htm



This is really well documented in 2020. It's a well-understood science, employed thoughtfully and logically in virtually all modern engines. The service you provide is very valuable and I know lots of folks appreciate it, but you just can't go around making inaccurate claims like this. There is a reason to using non-TTY bolts, but that reason isn't to improve mixed-materials street engines using MLS gaskets. It's just not. I would strongly encourage you to read up on this a bit more before asserting demonstrably untrue information.

CGman: Your quote:

"Geordi shouldn't need to measure any of these differences because the block and the head stay the same whether you use ARP or TTY bolts. Your concern is that the thermal expansion with ARPs will crack the head? (you didn't specifically say) Then the question would be whether the ARPs allows the connection to expand and retract the same as the TTY bolts. Geordi clearly gave his answer.

I know you have created an alternative design of thermostat housing that allows you to replace the standard thermostat easily with whatever temp thermostat you would like, but do you think that is what is going to fix the rash of cracked heads and leaky gaskets that plagues this engine design?

Also, do we have numbers on how many people with stock engine tunes have or have not experienced these issues?"


My concern is with the DIFFERENCES in thermal expansion between the aluminum cylinder head and the iron block it is clamped to. TTY bolts are designed to allow this to happen. ARP head studs not specifically designed for this engine do not work properly; hence they will contribute to the chances of the head cracking. It may be possible for ARP to design a higher quality fastener for the CRD engine cylinder head that will allow many thousands of heat cycles in a stock, grocery-getter consumer grade application, but that is not the focus of their business; the competition, racing and high-performance market is. When you factor in how comparatively rare this engine is, it simply would not make sense for ARP to spend the R&D time doing this; they would never recoup their money out of such an endeavour.

I have called ARP on 3 or 4 separate occasions to inquire about this and they have replied every time that they do not offer a kit for the CRD engine; full stop. The kits you see through parts suppliers like Sasquatch Parts and I.D. Parts are third party kits specified by the retailers themselves and do not have ANY ARP input or research and development in them; they are therefore not correct for this application. ARP has had to deal with this issue before, and has put out a publication stating that they do not suggest using their products for any application that they have not made a kit for.

For geordi to then make the claim - HOWEVER HE WANTS TO DESCRIBE HIS REASONS WHY - that the ARP head studs have the same stretch as the TTY bolts is patently ridiculous because he has no means to test this himself. He is not a materials engineer, and even if he was he certainly does not have to equipment to perform the testing. What is more, his recommendations fly in the face of the very same people who manufacture ARP fasteners. How it is possible geordi knows more about ARP head studs than ARP engineers themselves? Answer: he does not, plain and simple, and given some of the ridiculous things he has posted in the past about the CRD engine I would not trust him as far as I can throw him.

These CRD engine cylinder heads have a propensity to warp, and that propensity to warp greatly increases with poorly thought-out cooling system modifications; for example, the inline thermostat fix. The inline thermostat fix is something geordi has endorsed in the past, and he has never posted a statement retracting his endorsement. Most people now know that his short-sighted fix is bad for the CRD engine, because it creates a condition that changes a 2 circuit cooling system into a 1 circuit cooling system. When the O.E. thermostat fails, the bypass circuit is shut down and the only control of coolant is through the radiator circuit. When the inline thermostat is closed, there is no proper coolant flow though the engine and this creates hot spots in the cylinder head, contributing to the head warping and exhaust valve failures.

In a startling response to presenting geordi with these facts a few years ago, he posted on several occasions that coolant from other circuits like the EGR circuit and the heater core circuit are adequate to keep this from happening. WTF? Where is his expertise, where is his evidence in the form of any meaningful testing to back up his claims? The arrogance of this man is palpable.

There are other examples of geordi’s lack of understanding on basic engineering principles, like his opinion that the CRD engine fuel pre-heater is not necessary. He conflates the reasons why the fuel pre-heater is there in the first place, and then presents us all with B.S. calculations that do not even have all of the numbers necessary to do a proper calculation, like the volume of the fuel pre-heater chamber, the fuel flow rate and the actual wattage of the heater. He guesses at all of these parameters, and then expects us to accept his calculations.

With regards to your question about the Hot Diesel Solutions Model 001 and if it can fix the CRD head waring/cracking issue; I can definitely say that it will not do so. HOWEVER, because the Model 001 is and exact copy of the design and function of the O.E. thermostat assembly, it will not make a bad situation any worse like the inline thermostat fix will. The Model 001 respects the design and the integrity of the CRD engine cooling system; it is simply far better than O.E. because it is extreme quality, it is serviceable and it flows a lot more coolant in heavy demand situations than the O.E. thermostat possibly can.

I do not have any numbers whatsoever on the numbers of CRD owners who have left their engine tunes stock and any perceived related outcomes of cylinder head issues. I do not believe anyone has these statistics. A mild engine tune should never have any adverse effects on cylinder head integrity as most tuners would not tune an engine so radically as to cause these problems.

I am quite certain that cylinder head issues are more related to the planned obsolescence designed into this engine by using aluminum head/iron block architecture and by the driving habits of CRD owners than anything else.

geordi: If I thought it was necessary to give exact specifications for the cylinder head and the engine block, I would have done so.

The point that you seem to keep missing here is that when there is a lot of two different kinds metal to deal with, the thermal expansion differences between the two are a real problem when you try to clamp them together. This is the problem we have with aluminum head/iron block architecture, and several people have now pointed this out to you. There is also ample evidence that can be researched online regarding this whole issue that will support our side of the argument. Your continuing adherence to your narrative shows a wilful blindness on your part.

I think some of you guys must have cabin fever from lockdown.
There are plenty of opinions being expressed & like most things, everyine has one.
How about we take a deep breath & realize that the 428 engine has its weaknesses & many have their own opinion on how to improve it.
Is there anyone making comment that has a ME in mechanical engineering with a major in fastener design? If not, then all we have is a number of little boys seeing ho can wet the highest on the urinal!
Practical experience only counts for so much. When people try and justify their claims using little bits of theory we end up with a slanging match.
Time to stop throwing sand at each other in the sand box!

_________________
Australian KJ CRD 2006

I don't think anyone is saying that *any* mass-produced mechanical doodad is perfect, or that the 428 specifically has no room for improvement. I'm sure everyone agrees that you can throw money at almost anything and make it better.

But asserting demonstrably false information and then using it as justification for changes is a double-disservice - one, because it may cause people to spend time or money on things that don't actually improve the situation, and two, because it may cause people to put at risk things they never intended to.

Saying things like "TTY bolts behave plastically" or "TTY bolts are installed for robot convenience" is just inaccurate, and there is more or less an unlimited amount of data and paperwork which refutes that position. I'm not talking about "some dude on some one forum said..." I'm talking about articles, white papers, and studies from parts suppliers, manufacturers, and engineering organizations. Reputable people that all agree that the point of TTY bolts is to prevent damage to and enable superior performance from mixed materials engines. I cited three specific examples above, but you can jump on sae.org and read until your eyes bleed.

Similarly, asserting things like "ONLY PLACE in the engine that is over 220 degrees at any point is the actual combustion chamber" makes no sense. Coolant temps can reach 220F (or more!), and as we all know heat moves from higher concentrations to lower concentrations - if the coolant is 220F, something nearby is necessarily hotter in order to get it to that temperature. Combustion chambers reach 1000F or more; exhaust manifolds will trap a lot of that heat as long as the engine is running. While a cylinder head's *average* temperature might be in the low 200F range, during combustion areas of the head may see +50% or +100% temps for brief periods of time before that heat is conducted away by metal or water. At the same time, the engine block itself - especially in a cast iron engine - will see fairly consistent temperatures in the low to mid 200F range. The point is that *most* of the heat an engine generates is managed by the head and not the block, so the 2x thermal expansion coefficient of aluminum vs iron is *key* here... the head will expand *dramatically* versus the block, and it will expand/contract/expand/contract *constantly* while the engine is running. Molecules don't act on averages. TTY bolts, operating elastically, ensure consistent clamping forces in a way that non-TTY bolts absolutely, demonstrably cannot. It is, in fact, the point of TTY bolts.

Geordi also went on to comment about Germans making extensive use of TTY bolts outside of engines, but completely missed the point as to why. It's not for the robots. Nobody cares about the robots. Thermal expansion is not the only thing that might cause load on a joint - mechanical forces are also to be considered. A bolt operating near its yield (but not over) performs better than a bolt operating under its yield. This is why the bolts are torque TO yield, and not torque OVER yield. Where an engineer has gone to the trouble of calculating materials, loads, etc. a TTY bolt will be less likely to snap, and more likely to provide consistent clamping. Using TTY bolts on things like driveshafts, subframes, and torque converters allows those joints to remain tightly clamped when loads are acting against them and stay tight when that load is removed - that's the elastic behavior. Non-TTY bolts may shatter or loosen. That's superior functionality and it takes a LOT of engineering to get that.

I'm onboard with people solving problems and being creative in doing that. I suppose I'm also okay with irrational opinions about things. I have irrational opinions about Shell gasoline. But I'm not going to throw a bunch of technical words around to make you stop buying Shell gas. Mostly because I know some wise-ass is just gonna look up the MSDS on the internet and show me I'm being irrational. Anyway, point is: Use ARP studs and inline thermostats and copper spray on MLS gaskets if you want. Just admit the science doesn't back your play and that you're doing it because it makes you feel better. Because, honestly, that's the only reason to do those things.

Side note: I am not a mech e but the guy who does my manufacturing is. I'm sure he'll consult for the same favorable rate he charges me. However, where clear-cut documentation and citable passages exist, I always prefer to engaged him armed with the basic facts to keep my costs down. If Geordi would like to share some links etc. to documentation on his studs' suitability to TTY applications, or why robots like TTY bolts, or why my Saab's exhaust manifold is 1400 degrees when engines max out at 220, I'm all ears. My convictions are *all* subject to the best, latest evidence.

Bottom line; a person should always be safe and will not go wrong following Factory procedures, requirements, and instructions as laid out in the FSM by the engineers who designed and wrote the manuals.
But if a person chooses to ignore those instructions and wants to venture out and experiment on their own trying different things as some have done, there are always possible risks and associated costs involved if something does not go exactly as planned or envisioned. Unfortunately in some cases it could be an appreciable period of time elapsed before the actual detrimental side effects of an experiment goes awry and shows up as a failure.

These vehicles are going on 15-16 years old and some parts are no longer available new anywhere and some parts are getting very hard to come by, even some boneyard parts are becoming scarce. So please keep that in mind if you think about deviating from established factory procedures and recommendations.
It is your vehicle and you can do as you please to it, but at the end of the day, you are your own warranty provider.

_________________
Supporting Vendor and Moderator of LOST
05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount
98 Dodge Cummins 24 Valve

Never were truer words spoken!

Your post is basically telling all sides to calm down, and then you proceed to castigate all of us equally. Are you a progressive lefty?

Your post is insulting to those of us on the right side of the argument. There is one side who is clearly in the wrong here and that is geordi, not thesameguy and myself. Seeing that geordi has a following of supporters the two of us can see that this will have consequences for those gullible CRD owners who take his advice.

You clearly are not understanding what thesameguy and I are posting. We are saying to follow the well-documented history and engineering behind torque-to-yield bolts and the advice from the actual manufacturer of the head studs he recommends. You do not have to be an engineer yourself to follow an engineer's advice, UNLESS you want to make some of the questionable changes that geordi recommends... then you will also have to have the laboratory testing equipment to obtain the results to support your theories.

The engineering degree and the laboratory testing equipment are only required when you want to test new theories, not to follow established engineering principles and benchmarks or copy the original design. geordi and his supporters have attempted in the past to spin this around and make me spend tons of money on engineering studies to prove my product is safe when it is the exact same design as the O.E. part. He then had the unmitigated gall to state that his theories about the safety of the inline thermostat - which makes fundamentally bad changes to how the CRD engine cooling system operates - are sound simply because he says they are... no engineering degree from him, no engineering studies or laboratory testing to back his claims.

geordi also takes this skewed understanding of engineering and applies it to the TTY bolts, and to the exhaust valves, and to the fuel pre-heater. I see the same flawed and arrogant pattern of thinking in his posts on all of these subjects. I do not think he is a stupid man, but I do think he is attempting to create a narrative that results in business for himself.

Are you my long-lost brother? I do not think it is possible for me to post anything better than this!

I was trying to figured out this Layback guy too ???? I think you hit the spot right there !

Spring approaches and love is in the air...

_________________
Grumpy turtle from Finland, deep in a swamp at Balkans... Safe place in this unsafe world...

It's always the season for loving good engineering!

I am one of those with a fancy piece of paper hanging on the wall, but my specialty is not thermodynamics or fasteners. I think most of the TTY info is clear, but there are several things that I think may have been glossed over in this 'conversation'.

My decades of experience in the manufacturing world was building vehicles that were a lot larger and a lot faster than a Jeep CRD, but the production run was a lot smaller than the typical car or truck. One of the first things you learn is that just because 'the engineer' says something, doesn't mean it's right, or even if it is 'correct' it may still not happen. Who makes the decision? Marketing, engineering, production, etc. In just the engineering field you may have multiple people fighting over the 'correct' answer: cost engineer, stress, safety, weight, manufacturing, systems, etc. (notice I left out reliability and maintainability engineers for this example!) So is the iron block and aluminum head the 'correct' answer? Was TTY head bolts the 'right' answer? It depends on your viewpoint. I imagine cost plays a tremendous role in automobile manufacturing decisions; did it influence these two areas? Maybe not, but it probably influenced the decision to not put a fuel pump on the car, or to not relocate some of the gasser items that interfere with the diesel items that were shoved here and there under the hood.

Anyway, don't always assume the final design configuration was the 'best engineering' result, it's usually a combination of a bunch of choices.

_________________
#1 2006 Silver CRD Limited, flipped spare tire, ASFIR skids, GDE TCM & Ecotune, blue SAMCOs, 5V glow plugs, Rotella T6, intank fuel pump, Gen2 fuel head, new crank sensor, JBA 2.5 in silver package, Provent and ARB bumper
#2 2006 Metallic Green Limited; currently DOA
#3 2005 Silver project; currently not running...don't judge me

Totally - I think that's a completely fair assessment. Not apples to apples, but in a previous job I worked with a number of specialist automotive engineers who were tasked diagnosing failures in production automobiles. Those conversations were always illuminating, and always polarizing. I remember one guy who was working on a Ford E350 for us and we had some great conversations about its suspension & steering geometry, and the line Ford was no doubt walking between predictable handling and maneuverability... the context was snap oversteer resulting in crashes. Clearly, no "right answer" was available, just a series of decisions that ended up a specific result.

I don't think there is anything wrong with asking someone making a claim that isn't painfully obvious to support their position with evidence. I'll accept "the sky is blue" without much discussion. But framing a discussion about head bolts purely in the context of clamping force seems to overlook some key detail. I'm pretty sure that when mixed-materials engines first started showing up in the '70s the big counter-argument was that thermal expansion deltas would lead to short head gasket life. First we got composite head gaskets, then we got fancier TTY bolts, then we got crazy MLS gaskets. It doesn't feel like cost-cutting, it feels like progress (accepting of course aluminum heads themselves are, broadly, about cost cutting! ). If I'm expected to believe otherwise claiming "the hottest part of the engine is 220F" doesn't really set us up great. I'm gonna need some documentation.

Edit: This is a cool article on head gasket tech:

https://www.counterman.com/gaskets-from ... -vehicles/

There is some more info TTY bolts, but this passage describe the issue of "short head gasket life" I referenced above:

Maybe geordi should read these articles... thank you, thesameguy.

CGman; I agree with this assessment, and your evaluation of the reasons for why certain things were done and not done on the CRD, like the lack of a fuel lift pump. In the end, the bean counters make a lot of the final decisions.

It is my contention that the inclusion of an aluminum cylinder head itself was the limiting factor to the life of these engines, not the TTY bolts that hold them on. You need the TTY bolts to make the inclusion of the aluminum head viable. This is why I would LOVE to get iron cylinder heads made for this engine.

I don't really have a argument either way but I do wonder why the 2.8l in the Chevy colorado does have have a ARP kit if ARP is against / says they are bad for the engine design (aluminum head, iron block)? I realize it is slightly different design but what makes it OK for that engine but not the Jeep 2.8L?

https://www.dieselarmy.com/news/hot-off ... r-duramax/

https://www.sdptwins.com/2-8l-duramax-arp-head-studs/

https://www.coloradofans.com/threads/ar ... ds.419903/

Colorado engine info:
https://www.dieselworldmag.com/gm/%ef%b ... l-duramax/

_________________
2005 Liberty CRD, 245/75R16, OME CRD Springs front, OME HD rear

I saw that earlier this year, and I'm not sure this actually exists.

If you go to ARP's website, they list no such kit. Only kits for the 6.6l Duramax. Searching the part number gets you to a page that says "not available."

If you read the threads on the Colorado forums, there is only one vendor who carries this kit, a company called Screaming Diesel Performance. No other place on the planet has this kit. A local tuner, who is an ARP dealer, could not find this kit and their ARP rep couldn't either. The part number shows up in various places like Amazon and Summit, but the descriptions are always wrong.

I believe this is the same thing as various CRD vendors have done - someone pieced together ARP parts and now sells them. It's entirely possible Screaming Diesel Performance just ripped off Lost Jeeps.

To that end, nobody is saying "never use ARP studs." If you're building some coal-rolling, compound turbo, propane -injected 2.8l, these are the things that may keep your engine together. But that'll be a tradeoff - because you are absolutely sacrificing the intended function of an MLS gasket + TTY bolts for MAX CLAMPAGE. If you don't need that function, why make that sacrifice? That's the tangent of this thread: Not "don't modify," but "modify for the right reasons." Exactly what WW said a few posts back.

This is the best post in this whole thread. There are multiple factors for what comes down to business decisions, never mind that there are sub par individuals working in every area.

I interact with mechanical engineers on a regular basis. Some are really smart guys who are willing to listen. Some are smart guys who are complete asses. Some need a flashlight since it has to be dark when your head is so far up your arse.

What do you call the doctor who graduated last in his class........doctor.



Sent from my SM-G965W using Tapatalk

_________________
2006 Liberty CRD Limited

Provent @ 43,000 km
SEGR in progress
SAMCO Sport hoses @ 48500 km
Goodyear Wrangler Duratrac LT225/75R16

Reading the articles you posted in your tread would be a good starting point:

"companies are finding ways to modify these engines into making much more power and torque than they did from the factory. With that, you can expect increased engine pressures including cylinder pressure. Luckily for us, ARP has adapted to the new engine platform and now offer a full cylinder head stud for it."

If you want to make a 10sec drag racing Colorado diesel you might want to upgrade the head bolts and many other things !!!!