Below is info from Ken Neal (BulletProofDiesel):

Victor-Reinz/Black-Onyx Headgaskets, Why IMHO they fail
<HR style="BACKGROUND-COLOR: #ffffff; COLOR: #ffffff" SIZE=1><!-- / icon and title --><!-- message -->After having experience with both selling these gaskets and in having to reinstall OE head-gaskets on vehicles that have had the "Black Onyx" gaskets installed, I decided to try and find out why the Victor-Reinz/Black Onyx gaskets fail and why the OE gaskets seem to last.

What I found was surprising.

Both brands of head-gasket consists of 5 layers of stainless(?) steel.

Both brands of head-gasket have a thinner layer (#4 up) with a folded ring that most likely acts as a fire ring*.

(*go here:ATS Diesel Fire Ring Head - 1039203278 | OC DIESEL for a picture of a fire ringed head)

Both brands of head-gasket have multiple (3) layers with a sealing(?) compound applied to both sides of the layer.

The OE gaskets use a blue sealing compound, the Victor Reinz use a black compound. Two of the three Victor Reinz layers with the sealing(?) compound on them are completely covered. None of the OE gasket layers are completely covered.

The measurements below pretty much spell out why the gaskets most likely fail in my humble opinion(IMHO). They were measured top (#1 up) to bottom (#5 up) as they would be installed on the engine. The OE gaskets were all measured on bare metal. The Victor Reinz were measured on bare metal where possible. The most notable difference was between the 3rd and 4th layers. Each brand of gasket has a built in "fire ring" on the 4th layer. This is where the layer is folded back on itself creating a "fire ring" around each cylinder opening. I believe it is the difference in thickness of the built in "fire ring" that could cause the Victor-Reinz/Black-Onyx head gaskets to fail more often. Also, the overall thickness of each layer could play a role as well.


Ford OE:

#1 up) .010" Bare metal

#2 up) .015"

#3 up) .010"

#4 up) .007" The "fire ring" fold is .014"

#5 up) .010" Bare metal


Victor-Reinz/Black-Onyx:

#1 up) .010" Including black coating

#2 up) .015"

#3 up) .007"

#4 up) .005" The "fire ring" fold is .010"

#5 up) .010" Including black coating
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summary:
the total difference between the two is only .005 and the fire ring fold difference is .004 with the Ford OE being thicker. Also, the thicker the "fire ring", the more clamping force is applied at that location.

Thanks Ken for your work and sharing what you have learned.

 

Good info to help further all our knowledge of these trucks and their systems.

I wonder how much of a part the unknown sealing compounds play in the success or failure of each product.

I'll have the blue one please.

 

bump .

 

Ken says "the thicker the fire ring the more clamping force is applied at that location" can you explain what causes more clamping force by altering the thickness in the fire ring area?

 

The way I read it is that there is always a certain amount of variability in the flatness of the heads and block. The gasket components must be thick enough to enable full clamping force (pressure applied against surface area) to be exerted.

 

The clamping force would be distributed evenly regardless of the fire ring height which is approx. 32 tons based on 4 bolts and assuming they are made of grade 7 material.

 

Only on a perfectly flat surface

there is also a slight increase in surface area due to the compression.

 

I would also suggest that the thinker the firering the more/greater distace the head can " float" off the deck prior to losing the seal.

As stated a thick gasket in theory will give you a greater clamping force then a thinner one.

One could also wonder if the excessive coating is in reality allowing the head to float and shift under high load more then one would if there was less "glue". maybe a simple case of less is more going on.

 

I would also be very inclined to agree with the statement in bold red.

 

Can anybody come up with facts that actually show a thicker gasket has more clamping force? The torque applied to the fasteners (bolts, studs, screws) is what creates clamping force and everyone of those 14mm bolts is putting approx. 16,000 lbs. of force on the gasket.

 

The gasket has multiple components. The fire-ring area is the most critical and it will be thicker than the thickness of the metal layers so it can compress as the studs are tightened. Remember - force is the pressure applied to a surface area (pressure times surface area). Also, the torque you previously alluded to is the pressure exerted on the wrench multiplied by the length of the wrench - it is not the same force as what is applied at the fire ring .... that force depends on the surface area of the fire ring and how much it deforms before the head contacts the other surfaces of the gasket.

If you have a sufficiently thin fire ring, it will not get much force applied to it before the head contacts the other surfaces of the gasket (ie all of the coating, etc.).

Also - Are you disagreeing with the logic of imperfections in how flat the head is and the fact that thicker fire rings will provide a better sealing on mperfect surfaces??

How can you prove that .......................... ??
When you ask for proof on the internet you are practically asking the impossible - waste of time IMO. It is a discussion forum. Make your case and let each person decide.

 

What I'm most curious about, is what the manufacturer of Black Onyx (a. k. a. Victor Reinz) gaskets are doing, if anything about this sudden wave of repeat failures. We aren't talking about one or a couple incidents here. It seems only like yesterday, that the owners of these trucks were singing the praises all over about these gaskets. Now, with so many of them failing, I'm sure the owners of these trucks are real happy campers. I can't imagine what this has done to their sales.

 

But just a year ago many were promoting these gaskets as the cats meow for the guys who wanted all this horsepower. When I mentioned the compressive clamping force of approx. 16,000 lbs. per bolt I never mentioned foot pounds of torque or how long the wrench was. That force is based on 150 ft. lb. of torque dry for a 14mm bolt including the K factor. And I am sure you know the 14mm thread pitch is also a factor. Just out of curiosity I would like someone to post actual data why there is more force on the fire ring then any other part of the gasket.

 

iirc the bolts are 12mm on a 6.0 and 14mm on a 6.4. also I dont know were your getting a spec of 150ftlb as that is wrong too.

 

LOL - why would you even install a fire ring if it wasn't going to have more force exerted on it than the bulk of the gasket material ............. doesn't make sense.

You might as well also be asking for proof of the materials of construction used by each manufacturer to verify the physical properties of the metals and the soft goods?? They play just as important of a role ..................

Anyway - fact is that there are "structural differences" in the two gaskets and the BO/VR have a higher failure rate. Nuff said IMO.