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View Poll Results: O-Ringing: Whats it really matter
Block O-Ringing 6 54.55%
Head O-Ringing 1 9.09%
Doesn't matter one or the other 4 36.36%
Don't waste time and money O-ringing isn't worth it 0 0%
Voters: 11. You may not vote on this poll

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Old 06-08-2006, 04:14 PM   #1
MY99 2.5GT
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Member#: 5030
Join Date: Mar 2001
Chapter/Region: MAIC
Location: Martinsburg, WV, USA
1999 Legacy 2.5GT
19 Audi RS3, 13 Armada

Default O-ringing: Head or Block which is better?

Ive heard of folks o-ringing their heads and Ive heard of others o-ringing their block. Which is better or does it even matter?

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Old 06-09-2006, 06:39 PM   #2
Scooby Newbie
Member#: 92852
Join Date: Aug 2005
Chapter/Region: Tri-State
Location: NYC

I have been wondering the same thing. I just drop off ej22t block at the machine shop to get cleaned up bored and honed, and need to decide if I want to get it oring or get the heads oring, or not even bother with it. I don't think it really matters in regards to Oring head vs block. But let me add some food for thought.

-on an open deck block even thou an o ring is really small I would rather have it in the head.
-It is easier to take a pair of heads to a machine shop than a block (Moot point if you are rebuilding the entire engine)

And let me add a link and a picture. Maybe it will inspire people to get a good technical intelligent discussion going.


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Old 06-09-2006, 11:48 PM   #3
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Member#: 12163
Join Date: Nov 2001
Location: West Palm, FL
2002 WRX


To my understanding o-ringing the block or the head prove to be about equally effective. That said I would say it depends if you want to have receiver grooves machined. The most conventional method is to machine and o-ring the block, then machine receiver grooves opposite the o-rings in the heads. I guess it can probably be done in reverse fashion as well.
As far as the receiver grooves are concerned, it not only helps in high compression and or boosted applications, but helps wet motors from losing fluid which is a common problem with copper head gaskets. It allows the o-ring to literally push the gasket into the receiver groove to provide a better seal. Speaking of copper gaskets here is a bit of info from SCE regarding this stuff;
O-ring grooves may be cut in either the block or cylinder head. When using copper head gaskets thinner than .050, O-ring height should be no more than 25% of gasket thickness. For instance, the proper dimensions for an .043 thick gasket using .041 wire would be; a .038 to .040 groove width (provides a .001 interference fit), and a .032 groove depth (leaves .008-.010 of the wire protruding above the deck). This machining can be done at most high performance machine shops

When receiver grooves are necessary, alignment of O-ring and receiver groove is critical, as is the depth and width of the receiver groove. Generally receiver groove depth should be 75% of the O-ring protrusion and the receiver groove should be 1.5 times the wire width. Example: If the O-ring is .041 wide and .015 above the deck; receiver groove should be .012 deep and .060 wide.

While the machining of O-ring and receiver grooves must be done by a machinist, the installation of the O-ring wire can be done by anyone, using common hand tools. When tapping O-ring wire into the groove, use care to avoid denting the wire. SCE provides an O-ring installation kit, (SCE PART #31542) which includes instructions, an installation tool and O-ring wire. When cutting stainless O-ring wire, file the ends square to provide the tightest possible seal.

I've got a 2.2 closed deck in which the block was machined and o-ringed. My heads are currently getting cc'd and I have yet to order gaskets or machine receiver grooves. I'll post with updates in a few days.
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Old 06-10-2006, 01:51 AM   #4
Homemade WRX
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Join Date: Mar 2003
Chapter/Region: MAIC
Location: Mooresville, NC
96 3MI Racing
search FIRST, then PM!!!


I'm interested in doing this for my high pressure build...keep the technical discussion up (for those of you who know)
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Old 06-11-2006, 03:49 PM   #5
Scooby Specialist
Member#: 107276
Join Date: Feb 2006
Location: north london England
99 V.R.Special
WRC blue


mate ! no offence but thats not realy good o ring sealing!
click on the site, unfortunatly i cant directly link the page, you want to click
in line shop, its the 3rd from the left on top of the main pic
wrc engine mods
and then have a look at the o ring they do! also instead of gaskets look at there solution!

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