6.4 Iron head oring protrusion

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Up till now I've got all my orings set to .006 protrusion. I've seen guys go .008 and even more on aluminum heads.

What is safe and at what point is the coolant passage seal an issue?

Working on some higher hp stuff so be interested In trying more protrusion.
 

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I think we ran .008-.010 on our race truck, but we also had one cut into the deck of the block for a dual o ring setup. I’ll check tomorrow for the spec we were using.


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TRUBBS

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I think we ran .008-.010 on our race truck, but we also had one cut into the deck of the block for a dual o ring setup. I’ll check tomorrow for the spec we were using.
im interested to know what you come up with also, I have always heard .008 was the ticket, but also recently seen a post on FB that some are going as tall as .011, but that opened a whole new argument of how much is to much before it starts cutting into the gasket instead of clamping.
 

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Up till now I've got all my orings set to .006 protrusion. I've seen guys go .008 and even more on aluminum heads.

What is safe and at what point is the coolant passage seal an issue?

Working on some higher hp stuff so be interested In trying more protrusion.
I always had heard .008 was the magic number as well.
Are you cutting them in yourself or having a machine shop do them?
 
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My machine shop is doing it.
I have a set of aluminum 6.0 heads from kdd that are .011 but I would think the aluminum would take up some of that
 
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I think we ran .008-.010 on our race truck, but we also had one cut into the deck of the block for a dual o ring setup. I’ll check tomorrow for the spec we were using.


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That's a 6.0 correct?
The 6.4 has more clamp load so probably can't go quite as aggressive.
 

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That's a 6.0 correct?
The 6.4 has more clamp load so probably can't go quite as aggressive.

Sorry been stupid busy at the shop, didn’t get a chance to look at what we use for protrusion. I’ll try and do it Monday for ya.

Yeah it’s on a 6.0, I think kdd uses the same protrusion, just different placement for the bigger bore.

We did cut a 6.4 block and heads at the shop once, as the previous “professionally” done motor build didn’t have correctly torqued head bolts, at least according to my 1/2in gun (no Ugga duggas coming off), and then the head and block prep appeared to have been done with a chainsaw, and had deep scratches going thru the fire ring area of the head gasket clamping area on both the block and heads. Guy couldn’t afford a new motor, so we offered to give that a shot, with no guarantees it was gonna work, and luckily it did work for him.


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Sorry it took so long…

On the 6.4 I’ve got 4.295 for the oring od, .008-.010 protrusion for the head. On the block I e got 4.425 od and .006-.008 protrusion


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No worries
Interesting, thanks for the info.

You do the same protrusion on the 6.0?

Didn’t have 6.0 specs written down. Think every time I’ve had to do a 6.0 we’ve called kdd for the specs. We don’t o ring much at the shop anymore.


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TRUBBS

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Didn’t have 6.0 specs written down. Think every time I’ve had to do a 6.0 we’ve called kdd for the specs. We don’t o ring much at the shop anymore.


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I think KDD is .011. I have been cutting all mine at .008 for the 6.0 might try and go .009/.010 after this thread and hearing of KDD doing .011 (cant recall where I seen them say they do .011, maybe one of jareds posts on FB. I wondered if they would have been willing to share their specs if someone called them or not
 

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