Posted By: crscuda
Hemi head gasket selection - 07/21/10 10:29 AM
Who has the best head gasket for 2G hemi. Stock bore with 10.5-1 comp.
Hemi head gasket selection
Posted By: HPMike
Re: Hemi head gasket selection - 07/21/10 11:06 AM
Cometic 
Posted By: Dragula
Re: Hemi head gasket selection - 07/21/10 11:27 AM
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.
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.
Posted By: HEMIFRED
Re: Hemi head gasket selection - 07/21/10 01:37 PM
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.
Posted By: BCFKody
Re: Hemi head gasket selection - 07/21/10 07:13 PM
Dragula, How do the steel shim head gaskets work with aluminum heads? Do they damage the deck surface of the heads? Thanks!
Posted By: Dragula
Re: Hemi head gasket selection - 07/21/10 08:26 PM
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.
Posted By: HPMike
Re: Hemi head gasket selection - 07/21/10 09:00 PM
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
Posted By: Dragula
Re: Hemi head gasket selection - 07/21/10 09:13 PM
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.
Posted By: torkrules
Re: Hemi head gasket selection - 07/22/10 01:39 AM
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.
Posted By: crscuda
Re: Hemi head gasket selection - 07/22/10 01:59 AM
Thanks for all the input everyone.
Do the cometic and steel shim gaskets need special surface machining?
Do the cometic and steel shim gaskets need special surface machining?
Posted By: HPMike
Re: Hemi head gasket selection - 07/22/10 02:23 AM
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