O-Ring cylinder head?

[sethron71]

Hey guys,
Well I have never had much headgasket problems until the motor I am running now so I thought I would try something new. I am looking to o-ring the head. Actually machine a groove for a 1/16" o-ring around each bowl and around the water and oil jackets. I am not planning to do every water jacket but rather just go around the perimeter inside the studs and then each oil galley will get an individual o-ring. I have done quite a bit of research and it seems do able for sure. I talked with my local rubber and o-ring specialty shop and we came up with using Viton® Fluoroelastomer which has a Dura of A90 and can handle up to 400 degrees. I still need to do a bit more research to find out the actual temperature that close the to bowl. But the o-rings in a proper groove can handle 2500psi and would actually give a little if I ever lifted the head under boost vs a MHG which obviously has no give! I may end up having to machine the bowls out a bit to drop the compression back down a bit due to the dropped deck height without a gasket.

Obviously I have easy access to the CNC and can do this in a day but I am guessing no one really does it because of the cost it would incur for a one off design and research project. I also see people using brass compression rings and even stainless wire as a hard seal. So brass inserts with o-rings around the water jackets and oil galleys is another option.

Let me know what you guys are thinking and the pros and cons or if I am just flat crazy!!

Seth

 

[toyotanos]

note: I think you would be better served putting the grooves into the block- machine the head (were it to lift/warp) one time and you have to re-do everything.

I don't know what issues you have been having, but a properly machined head and block should have no issues sealing and holding gobs of power.

Pros:
No more buying MHG's
It could theoretically raise your CR.
When properly set-up, O-rings can hold enormous power.

Cons:
I remember reading a lot of threads about this back when I just signed on SM, the general consensus being that there wasn't enough clearance between the cylinders for it to be a strong modification. It could work, but it was more likely to fail given the fundamental block shortcomings.

If you lift the head, the O-rings would fail just like a MHG, in fact the O-rings would have less 'give' than the MHG since the MHG has the raised beads (and stopper ring in the HKS stopper) and acts somewhat like a spring.

Your piston must be ~1mm below the deck height- .040" is the general spec for piston-head clearance in performance engines. Any less and you run the risk of hammering the pistons into the head.

That's a lot of O-rings to keep retained the the grooves as you install the head, any one them gets dislodged and you're doing the whole job over again.


That's just what I can think of right now, perhaps I'll come up with more later (at work atm)

 

[SWD Fredester 3]

I agree with Steve on the cons. The build in my car at the time that you drove it had an O-ring head with a copper HG. Of course at that time it also had a boost leak. About 3 days after I found and fixed the boost leak-just a loose clamp-the HG blew. I also had a conversation with Ian about the cons and the lack of clearance between the cylinders. The shop that did the head used that set up on a number of high HP VWs, it worked well on those motors but not on a 7M.

 

[oldsking]

If don properly it should be fine. Most High power race cars run an O-ring setup system because it will seal far more superior but the key is to ensure the machine work is done perfectly.

 

[IBoughtASupra]

Just a suggestion, wouldn't a MHG and 1/2 ARP be good. I am not sure if that 7M head has that material for 1/2 studs though.

 

[AJ'S 88NA]

Don't you need a copper HG?

I have one if you need one.

 

[Zumtizzle]

Just a suggestion, wouldn't a MHG and 1/2 ARP be good. I am not sure if that 7M head has that material for 1/2 studs though.

The 7M's stock head hardware is 12MM.

12 millimeters = 0.472440945 inches

And to answer your question Yes there is enough material.

ARP has a new material they could custom make studs for you with. But they're pricey as fuck.

http://cartech.ides.com/datasheet.aspx?i=101&e=5&c=TechArt

 

[IBoughtASupra]

O, okay. I didn't know the stock sizes of the 7M studs.

If you call ARP, they would have a better idea on the rating of their hardware and what they could make.