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Old 12-27-2006, 06:40 AM   #1
saintluciascooby
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Default copper head gaskets and o-ring block

has anyone hear done this ?
did you o-ring the head and block or just the block?
what is the conclusion ? better than cometic gaskets?
Jon
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Old 12-28-2006, 04:33 AM   #2
bugeyes
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If using copper head gaskets the correct method is to O ring the block and heads at slightly different O-ring diameters.
Copper head gaskets give unsurpassed compression sealing but have a short street life. They tend to leak water and/or oil after a few thousand miles. They are ideal if you are racing and tend to pull the motor out at regular intervals.
If you are looking for long life street use (or just long life), go for an MLS type gasket such as genuine Subaru or Cometic (or similar). For these to work well the surfaces on the block and head need to be smooth and true as possible.
I have heard of guys running an O ring on the head that protrudes only a couple of thou above the surface and using the MLS gasket. The O ring just gives that extra but of clamp around the bore to prevent compression leaks. I have yet to hear of this being proven though and would consult with a reputable engine builder before doing this.
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Old 12-28-2006, 06:36 AM   #3
saintluciascooby
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Thanks for your input.

The car is only used on the1/4 mile track, and I have lifted a few heads while on nitrous using MLS cometic gaskets, the Rigoli brothers have sent me a set of 14mm head bolts, copper gaskets and orings to help/solve this problem.

I was hoping some one who has done this would speak up and tell of any pitfalls or tips when doing this.

Sam Rigoli told me the orings have to be exactly in the same place on the block/heads with their gaskets. their gaskets are thick so I am having to shave the heads to correct for compression.

Jon
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Old 12-29-2006, 02:05 AM   #4
bugeyes
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Beware - Thick head gaskets will increase the quench distance which will make your combustion chamber less efficient and more prone to detonation.
Thick head gaskets are normally only used as a last resort and sometimes as a "cheap" fix.
You would want your quench distance to be around 1mm or 40 thou. Less is getting too close allowing for piston rocking, greater is less efficient.

Shaving the heads is altering your cam timing from one head to the other. Unless you run adjustable cam sprockets (like me), you cant correct this and you r cam timing will be out. You may compensate for this to some degree with the thick head gasket but it will still have some error.

If your lifting heads I would be pointing the finger at the tune and not at head gaskets and head studs. You may fix one area only to have another let go. For instance if the heads dont let go you may destroy rod bearings or break ring lands.
Heaps of guys are making greater than 500hp with the normal ARP head studs.

You may not have your ignition timing setup to MBT (maximum best timing), to advance past this MBT point you are drastically increasing combustion pressure without any power increase. The engine may not knock but its still hurting.

Good luck
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Old 12-29-2006, 06:04 AM   #5
saintluciascooby
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Thanks for the tips. the car has been speced and tuned by Andy Forest performance. the engine is in the mid 700hp range at this point and we are seeing how far we can go.
the heads are just dressed and the block is adjusted for the gasket apparently the goal is .o35" squish.
I do have Jun vernier cam sprockets and we run race gas with now 20% methanol, det so far has never been a problem. the gasket thickness is what the rigoli brothers have found to work best for them.

Jon

Last edited by saintluciascooby; 12-29-2006 at 06:11 AM.
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Old 12-29-2006, 08:58 AM   #6
gumby647
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I think your last post said this but I'm not sure. You will want to correct for the gasket thickness by milling the block not the head. You will want to tighten the piston to head clearance back up and milling the head won't change that. If you had .037" P-H with the old gasket that was .020" and the new gasket is .040" taking .020" off the block will put your squish and cam timing back exactly like it was before. (all measurements are theoretical).
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Old 12-29-2006, 10:56 AM   #7
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which block are you running? a closed deck block would be the best canidate for an o-ring. roger clark motorsports has a lot of eperience with this. check it out.

mark



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Old 12-29-2006, 10:59 AM   #8
gumby647
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That's a different type of oringing. It doesn't use a gasket.
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Old 12-29-2006, 11:27 AM   #9
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right.
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Old 12-29-2006, 05:37 PM   #10
saintluciascooby
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Sideways7 that oring is for a polyurathane ring used on wrc engines .
Block is an EJ22T closed deck bored and stroked to 2.35 with built up EJ20k (STI V3) heads
gumby, yes skimming/dressing the heads and milling the block.
I still havent met or talked to anyone who has actually done it.
Jon
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Old 12-29-2006, 07:32 PM   #11
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i realized what i showed you wasnt what you were asking about. i was just offering it as another solution to a head gasket. the bronze rings are to help thermal properties at the squish point. the actual "o-ring" that goes around the combustion chamber to seal it is aluminum. then there is the rubber rings to seal the oil/water jackets. sorry, i guess this didn't help with what you asked. just trying to point out other options. roger clark is running some pretty impressive 1/4 times with a 2.0 set up like this.

mark
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Old 12-30-2006, 05:50 AM   #12
saintluciascooby
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Thats interesting I didnt realize RCMS was using this on there latest builds for some reason I thought they were using a metal head gasket.
Thanks for the input
Jon
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