Help with Cometic HG and 853 head
07-10-2006, 03:36 PM
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Help with Cometic HG and 853 head I have some 853 heads and cometic .040" gasket, when I tried to match the gasket to the head it appears that there is some holes that is covered by the gasket, are these not correct for these heads?
Look at the attached pic.
Look at the attached pic.
07-10-2006, 03:41 PM
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These do have the notch on, will these cause them to leak?
Originally Posted by GuitsBoy
Do the 853 heads have the notch that makes these gaskets leak? Maybe it was just the 806 castings.
07-10-2006, 04:03 PM
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Missing holes in the gasket If you look at the pic you'll see that the yellow circles (left side) does not have provisions for the holes in the head compared to the red circles (right side), will this also be a issue?
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07-10-2006, 04:06 PM
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I even sprayed copper gasket sealer on it and still blowing white smoke through the exhaust. Small chance of it just being the gasket sealer burning off that may have got onto the edges and into the cylinder/combustion chamber. Just drove it last night for about 20 mins will see again later today.
07-10-2006, 04:12 PM
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Originally Posted by GuitsBoy
well, if its not sealing because of the head recess, it would just leak out teh side of the block from under the head.
07-10-2006, 04:57 PM
#12
There are still holes in the area's you circled, there just smaller. Just like the holes in the middle. If you look at the block, the holes are long and narrow, but the gasket only has one small hole. I believe the small holes are supposed to go in the back if I'm not mistaken. You can also drill you another hole if your not comfortable with the small one in the gasket.
07-10-2006, 05:05 PM
#13
Wouldn't flipping that gasket horizontally fix the problem? You've got holes in the gasket where there are no holes in the head, and you've got no holes in the gasket where you have holes in the head. Is there something I'm missing here, I'm just trying to go by the pic here...
07-10-2006, 05:11 PM
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No, both sides of the head has the same set of holes/passage way, and those holes are only on one side of the gasket. Shouldn't they be on both sides?
Edit; I just looked at a MLS Graphite gasket and it has holes in both sides not like the Cometic.
Edit; I just looked at a MLS Graphite gasket and it has holes in both sides not like the Cometic.
Originally Posted by ArcticZ28
Wouldn't flipping that gasket horizontally fix the problem? You've got holes in the gasket where there are no holes in the head, and you've got no holes in the gasket where you have holes in the head. Is there something I'm missing here, I'm just trying to go by the pic here...
07-10-2006, 05:18 PM
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A sponsor, I'll contact them and talk to them about this. I'm not happy. 
Originally Posted by ArcticZ28
It doesn't look like there are holes on the right side of the head, of course I can't really see much from the small picture. They are obviously the wrong gaskets if the holes don't match up, who sold those to you and said they would work?
07-10-2006, 06:03 PM
#17
Originally Posted by Tri5Nerd
No, both sides of the head has the same set of holes/passage way, and those holes are only on one side of the gasket. Shouldn't they be on both sides?
Edit; I just looked at a MLS Graphite gasket and it has holes in both sides not like the Cometic.
Edit; I just looked at a MLS Graphite gasket and it has holes in both sides not like the Cometic.
I just looked @ my used GM stock graphite gaskets pulled from a 99. The gaskets have large holes @ one end & small holes @ the other. The large holes go over the rear & the small holes @ the front. I think GM does this to ensure fluid is flowing through the back of the block/heads. If the small holes were in the back, the coolant may find an easier path through the front of the head/block & limit rear circulation. On the stock gaskets, the front of the gasket is labled. The small holes are on the front side of the gaskets.
The Cometics that were installed in their place also had the small holes @ the front & large holes in the rear (back of the block/heads).
As to the notch/no notch, I haven't a clue other than to say that the Lingenfelter web site states that #853 @ #904 for 98, 99 & some 2000 heads have the notch & require the gasket specific to the notched heads.
07-10-2006, 06:15 PM
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Got an answer! Just talked to the shop and they said that the holes in the gasket should line up with the holes in the back of the block which makes sense now, I was just confused because the head has the holes at both the front and back.
As for the leaking with the notch, they told me to get some Permatex copper spray and spray 2 liberal coats on both sides waiting a few minutes between coats then waiting 5 minutes before putting and bolting the heads on.
Hope this helps and works.
As for the leaking with the notch, they told me to get some Permatex copper spray and spray 2 liberal coats on both sides waiting a few minutes between coats then waiting 5 minutes before putting and bolting the heads on.
Hope this helps and works.
