Re: Hemi head gasket selection
[Re: HPMike]
#754170
07/21/10 07:27 AM
07/21/10 07:27 AM
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Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
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You can pay the extra for the Cometics, you will get great sealing out of them, but they can reduce compression being so thick. I really like the stock steel shim head gaskets for a standard bore to +0.060" for the hemi. Sprayed with copper sealer, they are 0.17" when compressed and less than half the cost.
Things to check when you get the gaskets, especially the cometics, the push rod hole clearance, and how round or distorted the cylinder bores are. Had both issues with them, and none with the stock steel shim ones. Plus they took my 10.5:1 engine to just over 11:1, which was perfect in my book.
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Re: Hemi head gasket selection
[Re: Dragula]
#754171
07/21/10 09:37 AM
07/21/10 09:37 AM
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Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
HEMIFRED
master
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master
Joined: Jul 2010
Posts: 3,502
SOUTH JERSEY
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Quote:
You can pay the extra for the Cometics, you will get great sealing out of them, but they can reduce compression being so thick. I really like the stock steel shim head gaskets for a standard bore to +0.060" for the hemi. Sprayed with copper sealer, they are 0.17" when compressed and less than half the cost.
Things to check when you get the gaskets, especially the cometics, the push rod hole clearance, and how round or distorted the cylinder bores are. Had both issues with them, and none with the stock steel shim ones. Plus they took my 10.5:1 engine to just over 11:1, which was perfect in my book.
home of the
Sox and Martin Hemi Duster
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Re: Hemi head gasket selection
[Re: BCFKody]
#754173
07/21/10 04:26 PM
07/21/10 04:26 PM
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Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
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Quote:
Dragula, How do the steel shim head gaskets work with aluminum heads? Do they damage the deck surface of the heads? Thanks!
No issues. I have been running them for many years with my aluminum heads.
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Re: Hemi head gasket selection
[Re: Dragula]
#754174
07/21/10 05:00 PM
07/21/10 05:00 PM
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Joined: May 2005
Posts: 6,446
NJ-USA
HPMike
master
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master
Joined: May 2005
Posts: 6,446
NJ-USA
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Quote:
You can pay the extra for the Cometics, you will get great sealing out of them, but they can reduce compression being so thick. I really like the stock steel shim head gaskets for a standard bore to +0.060" for the hemi. Sprayed with copper sealer, they are 0.17" when compressed and less than half the cost.
Things to check when you get the gaskets, especially the cometics, the push rod hole clearance, and how round or distorted the cylinder bores are. Had both issues with them, and none with the stock steel shim ones. Plus they took my 10.5:1 engine to just over 11:1, which was perfect in my book.
I have been using Cometics for years on stock street Hemis. They make them .026"(special order) which is only marginally thicker than a steel shim. No more oil return leaks and use them indefinitely. You can't argue with the quality of the Cometics. And seeing all the Hemis I do with oil pouring out of the corners of the head gasket, all have steel shims.
I would like to see the "bore distortion" you refer to. Not trying to be argumentative, but I have never seen it and I have put together a lot of these.
MB
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Re: Hemi head gasket selection
[Re: HPMike]
#754175
07/21/10 05:13 PM
07/21/10 05:13 PM
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Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
Dragula
I Live Here
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I Live Here
Joined: May 2004
Posts: 12,393
Taxes & Virus's R-US, NY
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Quote:
I would like to see the "bore distortion" you refer to. Not trying to be argumentative, but I have never seen it and I have put together a lot of these.
MB
Returned them. Didn't take pics. The were all distorted as if they were stamped with dull tools.
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Re: Hemi head gasket selection
[Re: crscuda]
#754176
07/21/10 09:39 PM
07/21/10 09:39 PM
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Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
torkrules
I'm neurotic
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I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
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Quote:
Who has the best head gasket for 2G hemi. Stock bore with 10.5-1 comp.
I've had great luck with cometics. They make a set without the push rod holes. They just follow the contour of the block where the pushrods are. I spray them with Hylomar blue and they've never leaked. I've had many issues and the head gaskets were not one of them. I'm using a .027 on mine. I heard there might be a .021 available. They don't leave a mark on aluminum heads.
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Re: Hemi head gasket selection
[Re: crscuda]
#754178
07/21/10 10:23 PM
07/21/10 10:23 PM
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Joined: May 2005
Posts: 6,446
NJ-USA
HPMike
master
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master
Joined: May 2005
Posts: 6,446
NJ-USA
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Quote:
Thanks for all the input everyone.
Do the cometic and steel shim gaskets need special surface machining?
Cometics need a 50 RA or better finish. Most competent shops can give you that type of finish. It's almost mirror like, but I have had good success with sealing of cometics even with surface finish much rougher than the prescribed finish. Steel shims are less finicky here.
One tip I can give here is that if you decide to use a steel shim you can prep them with a rattle can silver paint. Spray it on evenly and mount the head while the paint is still tacky. Worked very well in those days when I used these.
I can't emphasize it any more, especially with the steel shims. PAY CLOSE ATTENTION to the oil drainbacks or you will positively get a nasty oil leak at the block/head juncture at the corners.
MB
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