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Thanks, yes I know, the question is which heads are more durable.
According to my information, ICON heads are available faster. Whether it's just marketing strategy, I don't know.
But the question remains how o-ringed heads can be refurbished.
Many sets of KDD cast heads out there with great results. For most all applications there is no need for anything else. Stay with the cast heads.
 
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Something else I just figured I'd ask. You did get the correct dowel size right?
 

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Hey Hartwig.

As you are aware from my posts over at FTE and my vids, my opinion is the 6.0L had is compromised by the spacing of the head fasteners (4 bolts per cylinder), which could have been dealt with if the heads were modified like the 6.4L heads with the stiffening ribs. The ICON heads are. I look at the multiples of the head casting numbers as a progression of changes, culminating with the 20mm design, both OE and the 20mm Service design heads, which use the 18mm injector clamps and rocker box, or carrier.

The 6.4L head is a continuation of improvement in design, using the stiffening ribs where the head has the potential to tent. If the production of the 6.0L had continued in the pickups, I think the stiffening ribs would have been incorporated into a 20mm+ design. There are still issues with the 20mm 6.0L heads, just not as prevalent (in the OE power level).

The implementation of o-rings is an enhancement to keep the gaskets from moving sideways and abrading the sealant when the center of the head tents; during high-pressure combustion events and when the distortion is wide enough (lift) to yield the material, and you end up having permanent tenting of the head across the width. Then there is even less head gasket compression at the center of the head, the weakest area of the gasket. The o-rings appear to be outside of the sprung fire ring of the design of the gasket, which is there to compensate for the head movement (tenting).

Aluminum alloys can have the same strength as the weaker cast iron alloys, but it would take a metallurgist to compare these two. The two issues against aluminum are the thermal expansion rate which can compromise the head fasteners and lower modulus of elasticity. I am more confident in aluminum heads when they are designed with the engineering backing and testing ability of the OE manufacturers. At the aftermarket level, you may hit a home run, but being conservative, I'll wait for 5 to 10 years of field trials.

If there were ICON cast iron heads, I'd not worry. It's where the progression should have been.

For me, what we are left with is 20mm factory heads and a good quality aftermarket iron casting with O-rings. The KDD heads seem to be that in the iron category. 20mm heads that are not severely hurt could have the o-rings installed, but people have had a good life with the reman 18mm heads with o-rings. I worry about the cracking above the injector cup with those, something it looks like the 20mm heads were addressing.

To your other question, o-rings have been field installed into existing grooves. You need to know the wire size and care in addressing the cap where the two ends meet. They typically are inserted with a plastic hammer. The problem is what to do if you need to resurface the heads, as that would reduce the depth of the groove but not the width. As you know, with your machining work, re-grooving the head on a mill would require precision centering. Easier done with a CNC and profiler. Or, if the grooves were cut using a tool such as BHJ's cutter and register plate, it could be recut as the registration would be the same if the same tool were used. I'm not familiar with the consistency tool to tool. With your ability, you could make one of your own. Those are not cheap.


I'm fine with my 20mm service heads without o-rings, I have no desire to run modified.
 
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Hey Hartwig.

As you are aware from my posts over at FTE and my vids, my opinion is the 6.0L had is compromised by the spacing of the head fasteners (4 bolts per cylinder), which could have been dealt with if the heads were modified like the 6.4L heads with the stiffening ribs. The ICON heads are. I look at the multiples of the head casting numbers as a progression of changes, culminating with the 20mm design, both OE and the 20mm Service design heads, which use the 18mm injector clamps and rocker box, or carrier.

The 6.4L head is a continuation of improvement in design, using the stiffening ribs where the head has the potential to tent. If the production of the 6.0L had continued in the pickups, I think the stiffening ribs would have been incorporated into a 20mm+ design. There are still issues with the 20mm 6.0L heads, just not as prevalent (in the OE power level).

The implementation of o-rings is an enhancement to keep the gaskets from moving sideways and abrading the sealant when the center of the head tents; during high-pressure combustion events and when the distortion is wide enough (lift) to yield the material, and you end up having permanent tenting of the head across the width. Then there is even less head gasket compression at the center of the head, the weakest area of the gasket. The o-rings appear to be outside of the sprung fire ring of the design of the gasket, which is there to compensate for the head movement (tenting).

Aluminum alloys can have the same strength as the weaker cast iron alloys, but it would take a metallurgist to compare these two. The two issues against aluminum are the thermal expansion rate which can compromise the head fasteners and lower modulus of elasticity. I am more confident in aluminum heads when they are designed with the engineering backing and testing ability of the OE manufacturers. At the aftermarket level, you may hit a home run, but being conservative, I'll wait for 5 to 10 years of field trials.

If there were ICON cast iron heads, I'd not worry. It's where the progression should have been.

For me, what we are left with is 20mm factory heads and a good quality aftermarket iron casting with O-rings. The KDD heads seem to be that in the iron category. 20mm heads that are not severely hurt could have the o-rings installed, but people have had a good life with the reman 18mm heads with o-rings. I worry about the cracking above the injector cup with those, something it looks like the 20mm heads were addressing.

To your other question, o-rings have been field installed into existing grooves. You need to know the wire size and care in addressing the cap where the two ends meet. They typically are inserted with a plastic hammer. The problem is what to do if you need to resurface the heads, as that would reduce the depth of the groove but not the width. As you know, with your machining work, re-grooving the head on a mill would require precision centering. Easier done with a CNC and profiler. Or, if the grooves were cut using a tool such as BHJ's cutter and register plate, it could be recut as the registration would be the same if the same tool were used. I'm not familiar with the consistency tool to tool. With your ability, you could make one of your own. Those are not cheap.


I'm fine with my 20mm service heads without o-rings, I have no desire to run modified.
That's something I was worried about too. AFAIK, a big problem with blowing HGs is the different rates of expansion and contraction. If the heads expand faster than the block, that has a higher chance of causing damage....right?
 

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Low clamping force on the injector hold down or a poor fit at the copper seal area -- really not much else

Need to check hole depth on the injector bore, the hold down bolt, and the clamp -- also pattern the copper washer area with something like Dykem

If the hole is "square" and the copper washer is "clamped" there would be no problem here
 
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The other holes that are not blowing seals would be the reference
 
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Discussion Starter · #28 ·
The other holes that are not blowing seals would be the reference
Yet, not blown yet. I figure comparing those that have blown to those that havent could show some kind of discrepancy if the cups are in fact moving after torqueing injectors. Measure from the top of the well down to the top of the cup maybe.
 

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That's something I was worried about too. AFAIK, a big problem with blowing HGs is the different rates of expansion and contraction. If the heads expand faster than the block, that has a higher chance of causing damage....right?


The more significant issue with the expansion is between the heads and the fasteners, the block trails. If the warm-up is gradual, both thermally expand at a similar but not equal rate. It's why the story of letting a diesel with its higher combustion pressure warm-up before generating higher power, and why in the later Ford programming people noticed they did not have as much power until the engine got warm, Ford compensated due to the warranty.

The block expansion also contributes to this as the threads are anchored into the depth of the block so that block expansion will occur between the thread's location and the block surface. Longer bolts are not as prone to failure, but the length has to be a design consideration.

When I had my multiple conversations with ARP, they brought this up. I'm using it in one of my video narratives. They stated the factory bolts continually yield with every thermal event (my rewording), which is why the factory bolts fail. There is some truth to that, but it only happens with each new higher running temp. When the bolt gets lengthened, it yields a new yield value, it work hardens. That is a perspective often missed when we comment on yielding bolts. The next time you have the same thermal ramp up, it's not going to lengthen microns, only if the head and bolt temperature differential is higher. We have factory-stock diesel that make it to over 300k.

I don't think we have much of a bolt issue as the story is told. As I've noted, including in threads on this forum, many people had gasket failures, did not address the heads (Ford warranty method), installed ARP studs, and had repeat failures in short order. If it were the bolts, there would not be an issue. ARP has told me the standard studs' preload (clamping force) is close to the factory preload. I'm not sure they got that right after talking to companies that do bolt testing. Each stud per ARP applies 27,000lbs of preload, 100,000lbs in total, 4x the stock peak compression pressure. That is a considerable safety factor. The more I look at the factory bolts, the more I believe they are an 11.8 grade, but testing is the only way to confirm that. That's a video where I'll be asking for help.

Rectangle Slope Font Parallel Triangle
 

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Poor-fitting cups that move would be an issue to the list of potentials, along with machining that was off.
 

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Would assume the cups are pressed in until they bottom -- What I have installed were hammered in with a tool
Would also assume the center line of the hole is concentric with the various steps and tool changes when the hole was cut
So that leaves the clamping force on the copper seal - (this is not a crush washer)
Have to question the torque
Also if the hold down assembly can surpass the clamping distance needed by the fit of the injector in the hole

Still all comes down to not enough force on the seal or a poor fit on the sealing surface
 

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Discussion Starter · #33 ·
Would assume the cups are pressed in until they bottom -- What I have installed were hammered in with a tool
Would also assume the center line of the hole is concentric with the various steps and tool changes when the hole was cut
So that leaves the clamping force on the copper seal - (this is not a crush washer)
Have to question the torque
Also if the hold down assembly can surpass the clamping distance needed by the fit of the injector in the hole

Still all comes down to not enough force on the seal or a poor fit on the sealing surface
When I get home to fix it, I'm going to check the distance on all the cups and give them all a good couple wacks with a hammer. That is, unless KDD tells me to do otherwise. My only other question is if the hold downs are correct. I guess if the heads were some how 20mm then my 18mm rocker boxes wouldnt have bolted up.
 

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The more significant issue with the expansion is between the heads and the fasteners, the block trails. If the warm-up is gradual, both thermally expand at a similar but not equal rate. It's why the story of letting a diesel with its higher combustion pressure warm-up before generating higher power, and why in the later Ford programming people noticed they did not have as much power until the engine got warm, Ford compensated due to the warranty.

The block expansion also contributes to this as the threads are anchored into the depth of the block so that block expansion will occur between the thread's location and the block surface. Longer bolts are not as prone to failure, but the length has to be a design consideration.

When I had my multiple conversations with ARP, they brought this up. I'm using it in one of my video narratives. They stated the factory bolts continually yield with every thermal event (my rewording), which is why the factory bolts fail. There is some truth to that, but it only happens with each new higher running temp. When the bolt gets lengthened, it yields a new yield value, it work hardens. That is a perspective often missed when we comment on yielding bolts. The next time you have the same thermal ramp up, it's not going to lengthen microns, only if the head and bolt temperature differential is higher. We have factory-stock diesel that make it to over 300k.

I don't think we have much of a bolt issue as the story is told. As I've noted, including in threads on this forum, many people had gasket failures, did not address the heads (Ford warranty method), installed ARP studs, and had repeat failures in short order. If it were the bolts, there would not be an issue. ARP has told me the standard studs' preload (clamping force) is close to the factory preload. I'm not sure they got that right after talking to companies that do bolt testing. Each stud per ARP applies 27,000lbs of preload, 100,000lbs in total, 4x the stock peak compression pressure. That is a considerable safety factor. The more I look at the factory bolts, the more I believe they are an 11.8 grade, but testing is the only way to confirm that. That's a video where I'll be asking for help.

View attachment 780851
Ah, gotcha. That is a good point to bring up with people still having failures. I think people just think adding ARP studs is a one time deal and they will never see another failure, so they throw 600 horsepower at it.

So have you seen the KDD "checked and decked" reman heads they sell? They are 1250 bucks and are oringed...
 

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A general question: are large truck engines all do have cast steel heads? Does anyone know any made of cast aluminum?
On diesel cars with smaller engines there are many examples where an aluminum head sits on a steel block, but on larger engines?
 

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Mark, maybe you already have this. There are changes to the injector hold-down clamp (bolt location) and rocker carrier unless you have the "service" 20mm heads.

Font Material property Parallel Screenshot Document
Rectangle Font Parallel Slope Schematic
Font Parallel Rectangle Art Diagram
 

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I have that TSB, but couldn't find where I put it, lol. In Figure 3 (the decision tree diagram if you will), it shows that if you have the wavy rails and the T45 hold-down bolts you can use the 20MM heads with the stepped dowels. ie use commonized kit 6C3Z-6049-A - same as what is stated for the commonized engine.

After reading that years ago, I just filed it away (erroneously) that they would work on an 05 and up. I definitely acknowledge I have done the work personally.

Edit - just wanted to admit a senior moment. For some reason I was thinking that the T45 hold downs happened prior to the "commonization". Clearly (now) that isn't so!
 
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