From my take, it depends on the diameter of the o-ring, not the wire. The Fel-Pro gasket has a wider fire ring so that the fire ring fold can be under the o-ring. The safer way to go is to stick with the OE or Mahle. Some head suppliers are fine with the Fel-Pro, and others are not.

 

aa ok ya I was leaning towards OE or the Mahle Black Diamonds originally was just thinking that maybe the Fel Pros would be a double whammy in terms of sealing potential

 

I used the Fel-Pro's, but I wasn't using o-rings, so their improvement in the gasket was a better fit for me. I consider their gaskets 'o-ring light'. They went out of the way in this application to build a more robust gasket to keep it from moving sideways at the gasket minimums, the same the O-ring does.

They could be additive protection but did not design the gasket for o-rings. Ultimately, it would be best to go with whatever the machine shop machining the o-rings grooves says to use. Presumably, they have checked fitment.

Had I needed new heads, I would have purchased O-ringed heads. But I was able to do what I could do in my garage, knowing my limitations or abilities. Plus, I was trying to show what could be done, not the ideal.

 

Aaa ok ok thanks for the informative post

 

A few years ago I recall there being a major issue with Mahle Black Diamond gaskets, don't remember what specifically.

Back when I did my heads the preferred choice was OEM or Fel-Pro. I went fel-pro and o-ring heads, still going strong.

 

I believe Kill Devil has no issues with the Fel-Pros. UFC certainly does.

 

Jack do you recall the Mahle gasket predicament or was it cylinder head manufacturer specific issues.....or am I crazy and have things mixed up?

 

There were Black Onix gaskets that were poorly made, often confused with Black Diamond.

 

Yes that was it. Thanks for the clarification.

 

I have about 60k on my KDD's and Fel-Pros with no issues
(I hope I didn't jinx myself)

 

Jared said they were fine.

 

When i did my head gaskets i was planning on running felpro's gaskets, and ordered them. Then last minute i decided to get kdd oringed heads, and after getting many opinions at the time, i decided to go with the oem gaskets with the heads, after having my gaskets fail with studs once already(black diamond,not black onyx). if i would not of gone with oring heads, i would of went with the felpro's. Im of the opinion that the black sealant of mahles gaskets isnt as good as the blue of fords, after having removed both, notsure what it is, but its more than just the colour i think.

 

That is the problem with engine "soft goods" (ie gaskets, sealants, and o-rings). No way to really know what you are getting.

It is a common way for the aftermarket to cheat you.

NOW - I am NOT saying that the black sealant on the Black Diamond gaskets is ANYTHING OTHER THAN the same material Ford uses - only a different color. Honestly, I do not have any proof of what it is - one way or the other.

 

When I still had my channel open to Fel-Pro and discussing the gaskets, they said they and Mahle were using FKM as the sealing compound. Ford was having a silicone base put on their proprietary head gaskets. The silicone has a higher temperature range, but the FKM is still above what the diesel will see.

The products we sold to Ford always had the contracts saying one and only channel to Ford. We could make a 'like' product, but it wasn't on their tooling (they pay for it) or with the formulation stated in their contract. I have a feeling that is what is going on with gaskets.

Plus, when you put the totality of the QC, tolerances, etc., used in OE, you can't market that in the aftermarket world - you are priced out. The thing that the aftermarket has is they can modify or improve things without the Motherships (Ford) blessing.

The Fel-Pro guy told me they looked at the failures, used their own dynos and head lift bench (Skokie), and vehicles (Skokie), holding off the design for the 6.0L until they had something they felt was better. But, of course, as an aftermarket company, they don't have the total resources to test at the end of the day.

I had known some of the people at Fel-Pro back from the mid-90s before both of our companies were swallowed up by Cooper and then Federal-Mogul. Every company in that old Cooper group, including Moog back then, was really into what they were doing and proud of their standing. Once part of Cooper, I got to know and work with the Moog R&D guys and did some testing for them.

But that was all the 80s and 90s, mostly up to 2005, before the idiots at F-M looked to see how they could reduce costs, destroying Moog. Fel-Pro was the holdout. And at least up to 5 years ago, they seemed to be grinding along. I believe their vehicle test guy is still there.

All we do is be part of the long-term test to see how this all goes.

 

Fluoroelastomers (FKM) are generally good stuff, but there are MANY subtle varieties of them. Some additives for extra heat resistance, some for chemical resistance, some to reduce movement under compression (compression set), etc.

Good to know that information.

As an FYI - viton is an FKM.

 

I'm another with KDD and felpro. Almost 40k.

 

I know that ficm repair sells felpro gaskets, and it says right on his site if your planning on using oringed heads dont use felpros, and go mahle or oem gaskets. I seen other places that also said the same, so thats why i ended up going oem.

 

As a vendor, a safer way to go. And with o-rings, you have nothing to worry about.

It's the guys who went studs, OE gaskets (or others), and no machining to flatten the heads that would typically blow the gaskets in ~20-25k.

 

Hmmm thanks for all the info guys ya see I got a gel pro gasket kit with my engine from the machine shop, I had asked for the mahle kit but he brought this one in and even if I don’t use the head gaskets I can’t replace all the other gaskets for cheaper so I took it. The machinist said the O ring protrusion on these are 6 thousands which is good in my understanding as far as cutting of the head gasket is considered. But im not sure for the diameter. Maybe I will call KDD and ask they’re opinion

 

If you have KDD heads, I don't know why you're asking.

 

I do not have KDD heads. I had my factory heads rebuilt and O ringed. lDD heads are like 5k to get to Canada after everything

 

KDD

 

so got the heads back and just a quick look comparing the fel pro gaskets it looks like the machinest did o ring diamater is pretty small so its close the the valves and it looks like it lands on the inside of the gasket sealing ring, i would assume that would be okay then

 

Post a picture. Does this shop routinely rework 6.0 heads and install o-rings in them?

If this shop is telling you to use the gaskets he provided, I guess he is warranting they work?

 

ya he does alot of these motors for one guy who only works on 6.0s but hes a machinist not a 6.0 guy as in i asked him about the felpros and he didnt have an idea they were any different then oem or the others. I know he does O ringing for that one guy just not sure what gaskets they used