I am happy with my commonized heads. I do wish I had had them o-ringed back in 2011 when the studs were installed. That said, can't complain about the service life that I have been blessed with for 11 years.

 

And they have been holding up with your tuning, too.

 

For sure, although I think I am going to an unlimited tow tune soon - for fuel economy (hopefully).

 

I have a hot tune from GH performance and never run it. It was nice to have a 600HP truck but it is worthless to me nowadays and stay in unlimited tow tune. The tow tune I had revised through GH still pulls hard unloaded and saves me some fuel.

I totally understand your point Jack, as I limped my truck around with compromised head gaskets for many years.

With the Fel-Pro gasket info you shared, I am glad I used the brand during my rebuild.

Thanks
Joe

 

Jack, you just talked me into using head bolts instead of studs, with o-ringed heads, of course.

The question now becomes "what or whose bolts to use?" because it appears Ford no longer sells them. I can't even find a part number for them that makes sense. A few ebay listings show 3C3Z-6065-AA but a search of that number only shows HGs. Can't find an International Navistar part number either.

 

Well, that's a situation. You'd get the full story if I can ever recover my video from my old computer.

There have been three versions of those head bolts sold by Ford under the same part number, which is highly unusual.

The original bolts from FerryCap and Screw had these markings.





When Ford/International came out with the Commonized engines in 2006.5, the same company made the bolts with a different head marking, which is not common to the industry, an "N". Considering I see that evolution as a change for a stronger engine, there may have been a change to the bolts, too. The "R" also is a special designation, the threads rolled after heat treating so they are stronger. ARP does this too.





FerryCap and screw were bought by Stanley and no longer make vehicle bolts which they sold to International, Caterpillar, Deere, and many other well-regarded companies. The bolts only come in the Ford Gasket kits for some time. The new supplier is a German-based company, with a plant in the USA. I'm not sure of any history with those parts.





A good while ago, I worked with Razzi with him shipping me used OE bolts for potential testing by the lab I mentioned, but I've also tried to measure the consistency of how much they had been stretched. That may be worthless as these bolts are not made to a tight length spec. Companies like CAT can have their head bolts machined to length so they can be checked in the field to see if the bolts can be reused, a common practice for highly stressed bolts that a tightened to close to yield.

Measuring one set of the new OE bolts I bought.




Since everyone gets rid of them, I bought multiple engine sets of new factory bolts off eBay for a ridiculously low price for possible testing if I can get the funds. With shipping, you can buy a head's worth of bolts for $25-$35. I paid $30 a year and a half ago for one engine set. I did install ARP studs in my engine, but for two reasons. First, a rebuilt engine without ARP studs is highly unmarketable in the marketplace, and second, I wanted to go through the tightening sequence to check rotation, torque vs. angle.

As I said, the 11.8 spec is a custom bolt, like the type ARP makes for many applications. Talking to the test lab rep, that's not uncommon, we are not very familiar that it's done, but there are many applications (bridges, etc.) where the bolts are not what is publicly available. The rep said these head bolts would be more expensive and have more controls than buying bolts of a 10.9 or 12.9 grade, as we could. I talked him into giving me an example of their graphs, which he did with a 10.9 grade in our head bolt size. Brilliant on his part.





The common bolt stress curve. The ARP studs are tightened higher than the "typical bolting or clamping load", confirmed with ARP, but under the yield, so they can be reused. They are a much "stronger" bolt than the stock bolt, but are not taken to the point of yield like the OE bolts are.





While the potential is there for the test lab engineer to "sell me", there is the possibility that the 11.8 14mm bolts are tensioned to a higher clamping force than the ARP studs are. That's not a statement that holds water until the bolts are tested, but that's not the testing method the lab would do. You have to do that in an engine with strained gaged bolts. ARP has not done that either; they just tested the OE bolts in a test machine. You would have to test used bolts to see where the new "yield" point is to tell the final clamping load in an engine. That prospect gets interesting.





I've also had discussions with a Ford engineer who works in the engine department, specifically the new 7.3 gas motor. He is a hot-rodder who does much external to Ford but doesn't want his work association public. He has publicly shown some testing he did with his LS racing engines; he works on both GM and Ford engines in his personal life. In that GM world, guys want to reuse TTY head bolts. You can reuse those bolts; stretched to yield makes a stronger bolt; ARP uses that process, too. But you lose out on the main benefit, consistency bolt to bolt.

From his data which he is allowing me to use. He also acknowledged it's typical to design to a 4:1 safety factor, which is where we are in a stock condition. If you want to pump to 600hp, the factory bolt safety factor is dropped to 2:1. Even with that, your clamping is twice the load. That would be uncomfortable for me.





Anyway, the point is we are looking at the wrong thing, expecting the ARP to be the savior. The problem is the engine's design; too few bolts and a lack of reinforcement in the heads to compensate for the deflection. You can get by in a stock power range and with a mild tune. But the tune may be a fine line when Ford tuning is already 60hp more than what International was targeting for their commercial engine. Remember, few HG failures with International buses and trucks.

​​​​​​​Talked way too much.

 

I disagree…..you didn’t talk way too much. These discussions are so important and very enlightening for those of us with less experience in the 6.0 PSD. This is great.

 

That was a mouth full, but probably less than the video, so thank you for the truncated version.

Makes sense that the gaskets come up under that part number if they are only sold as kits.

You could setup a go fund me account to raise money for the testing. If everyone here pitched in ten or twenty bucks it wouldn't take long to get to $1500.

 

TooManyToys

Just trying to make sure I'm understanding what you're saying. Are you saying no real performance difference between studs and bolts, just the cost difference is why you're saying forget the studs?

Also in regards to the deck surfaces, are the blocks staying flat and just heads are the problem or is that really documented one way or the other?

 

That's the plan, at some point.

 

Thanks for posting this Jack. I find this all very informative and very interesting and I do believe that you have gotten to the root of the problem. So many people read(and believe) that the ARP studs will solve all the issues. Unfortunately, as you mentioned you do need the studs in if you hope to resell and recoup some money back. If there is anything I can do to assist you in the machine shop feel free to contact me.

Rob

 

The only issue I've found with the block mentioned in my one video was a person who I believe works for International state; the 20mm blocks were strengthened in the head bolt thread area to reduce uplifting, along with the work done with the heads. However, I don't consider that a significant issue as people have gone over 600hp with o-ringed heads and studs.



If you want to push the engine to high HP, or you just want the insurance of having studs, and you expect you might be taking the heads off again (), studs are fine.



But the factory bolts are not the real issue here until you get possibly into the high HP range, and what drives me insane is that people installing studs are saying it's bulletproof. And the theory that the factory bolts are the problem has led to many years of people misidentifying the real issue. And that continues today.



O-rings have proven themselves, but people are doing two things when using rebuilt heads with o-rings. First, they machine the heads flat and then install o-rings. That's fine if you have the funds to do that. But you could spend $600-$800 on getting heads worked over to flat if you are not going to use a strong tune; you don't have to pay $2500+ for new heads.



For the high HP situations, KDD is now saying you need the higher-strength studs. But when you use them, ARP will tell you you need to use a torque plate and re-bore the engine because the cylinders will distort. I'm unsure if they ever measured that or if it's a general concept. While doing my deep dive discussion with ARP, I realized they never measured anything in an assembled block. They are a fastener company; they test the bolts/studs they will replace and go from there. It's a TTY fastener; we will provide a higher strength faster as a stud where the torque range (clamping load) is in the field of reusable (graph above). They do not do anything like the OE or aftermarket gasket companies do, measuring using an engine, the gasket crush, the compressive force across the entire surface, or the stress during engine operating power and temperatures.



I asked them why ARP studs are better than the factory bolts (where the discussion also went to stud vs. bolt tension values), and they said every time the engine heats up, the factory bolts stretch a little, and they only last 100k miles. We know of 6.0Ls that have gone for 400k to 800k on this forum. And from an engineering perspective, they may yield a little more with every new high-temperature maximum (why they fail with loss of coolant) due to head expansion, but it's a once and done at every high-temperature point. While that was being said to me, in my mind, I was thinking, "you're an idiot".



The fasteners will stretch against the thermal expansion of the block and head, but the bolts are heating up also, so it's a differential that is not so severe, such as when there is coolant loss. Plus, the heads will also expand in the less compressed direction of less resistance, the movement will be more horizontal to some extent, and you also have a compressive medium, the head gasket. Having a head gasket there makes the engineering way more complicated than ARP alludes to. And then you get into some really funky stuff related to the relative stiffness of all the parts. Including what is the stiffness of the iron of the head vs. the stiffness of the fastener. But the head gasket is the most compressive part of the sandwich, and why MLS gaskets are designed with "springiness", if that's a word, and why MLS gaskets have become the gasket of choice. A considerable difference between a bolted joint and a bolted gasketed joint.



And, of course, the gasket failures are outside the fasteners cone of compression or frustum.

 

I understand the math and the concept of clamping force that is achievable with bolts and studs. I am in agreement that the heads are the main issue (given the built in bolting design we have to work with). Well sort of. I think heat (along with the cylinder pressure) is possibly a close second when it comes to failure mechanisms.

All I know for certain is that I have had 11 years of a strong running engine on the SRL+ tune. 2006 commonized engine. The only indication of a potential issue is that a couple of times a month I vent off a small residual pressure in my degas bottle. It seems to only build when I work the truck with the air conditioner on. I have done that for a few years.

Would head bolts have stood up as well under the SRL+ tune? I don't know. My typical style includes periodic hard accelerations, but I do not "race" it, and my towing would be considered pretty light for the typical diesel crowd. Hauling (bumper hitch) 6k-8k loads on a trailer is occasional. Lighter loads a little more common, but still not frequent. No doubt that the actual experiences with studded engines falls short of the term "bulletproof".

My only caveat to this is that I am a nut about engine heat. My temperatures (especially when working the engine) are maintained a lot lower than most of the 6.0L people I know. As I said, I do not tow heavy loads. If I did, I may very well quickly experience a significant head gasket failure - with the head studs.

I just do not think there is anyone that can come up with a good model of what the heads, block, and bolts/studs, etc do when the temperatures get high. My opinion is keep the temperatures in normal ranges under all conditions and your chance of experiencing long term reliability will be significantly higher - in many of the engine components.

EDIT just to add - .... and I really cringe when people keep driving with white smoke from injectors over-fueling!!

 

I have some used bolts slightly stretched and only dropped once

J/K

Joe

 

Mark -

The people that could ain't talking; Ford, International, and probably companies like I worked for. I know the F-M engine component division has a huge engine dyno facility in Ann Arbor, where the crankshaft seals were developed, and Fel-Pro does at their Skokie, Illinois facility.

But during the prove-out work during development testing I know they push the vehicles and run hot. When we ran the brake fluid boil tests down Townes Pass, Ford, et.al. would run trailer and cooling tests uphill and in the valley. I know on the dynos they run to failure.

I think there are several contributing factors and it's would be hard to identify only one thing.

The bow in the heads can be due to several factors.

Casting stress (We see new out of the box OE cup. When that's bolted down, it's going somewhere)
Thermal stress
Combustion Pressure deflection

All three of those may contribute to the plastic deformation at the center of the heads. I never hit high temps, but I had 0.0005" bow in the center. Maybe if it had run hot, there would be more. Or maybe running hot only you would see more. I've never ran a tune, but I ran with EGR blocked.

Pete ran tunes and had a coolant leak, lost gaskets. Two gallons dry may be enough to not have the heads fully wetted. He was at 185k, where when you look at the thread I mentioned, people were loosing gaskets during warranty. The state of tune matters.





In that thread too, was another comment from Charlie. He mentions heat, but it's just a comment as we do.

The screenshot.





Anyway, I keep talking about my video. There is a lot I had talked about in this forum before I published the video. You are never going to get an absolute answer. I had run $250,000 worth of test on one vehicle platform developing brake materials and still never had all the answers. In 30 years, I can't say anyone person or company ever did. If there were, they would be on a Caribbean beach taking phone calls.

The video if not seen, I don't know if I ever linked it to this forum, I've stopped doing that. It's only one part of the story.