Head gasket questions....
Thread Starter
Joined: Sep 2004
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From: Michigan & Florida
Head gasket questions.... I have been told two different answers to this one question: One answer "Yes", and one "No"! Will the factory LS7 427 head gasket, which appears to be a "rubberized" MLS head gasket, work on an LS1 that has had Darton "wet" sleeves installed? I ran Cometics, which ARE "rubberized" MLS head gaskets, for 30,000 miles, and they are around $200.00 for a new set. The factory LS7 gaskets, which are only about $65.00 for the pair, are within .003" thick of being exactly the same thickness that my Cometics were, so that is NOT an issue. But if it will interface, seal, etc., why not save the $130.00 or so and go with the factory gasket, which is also easily and quickly, obtained? I am NOT tracking the car every week, and have never used a power adder, though in the near future I may go with a small (125hp MAX.) dose of spray. Anyone know for sure? The gaskets appear to be "almost" identical when viewed side by side, except the Cometic is totally covered in "rubber" whereas the LS7 is only coated around every opening. Anyone tried this with any success? Thanks.
I have been told two different answers to this one question: One answer "Yes", and one "No"! Will the factory LS7 427 head gasket, which appears to be a "rubberized" MLS head gasket, work on an LS1 that has had Darton "wet" sleeves installed? I ran Cometics, which ARE "rubberized" MLS head gaskets, for 30,000 miles, and they are around $200.00 for a new set. The factory LS7 gaskets, which are only about $65.00 for the pair, are within .003" thick of being exactly the same thickness that my Cometics were, so that is NOT an issue. But if it will interface, seal, etc., why not save the $130.00 or so and go with the factory gasket, which is also easily and quickly, obtained? I am NOT tracking the car every week, and have never used a power adder, though in the near future I may go with a small (125hp MAX.) dose of spray. Anyone know for sure? The gaskets appear to be "almost" identical when viewed side by side, except the Cometic is totally covered in "rubber" whereas the LS7 is only coated around every opening. Anyone tried this with any success? Thanks.
Thread Starter
Joined: Sep 2004
Posts: 3,212
Likes: 1,612
From: Michigan & Florida
Thread Starter
Joined: Sep 2004
Posts: 3,212
Likes: 1,612
From: Michigan & Florida
Thanks. Steve is one of the two answers I have gotten. However, Steve said he had "heard" this to be true, and that at that point in time, at least, he had NOT yet tried one for a build he was doing himself. Tont M. was the other response. Not trying to start a fight, but not wanting to find out that someone is wrong "the hard way", i.e- I have Evans coolant (At $30.00 per gallon!!) all over the garage floor and.... I'm sure you get the idea. Thanks again.
Straight answer is this...
The stock LS1 5.7/5.3HO GM MLS Gasket has a bore diameter of less than 4", I didn't make an exact measurment, I just know it was at least .030" less than 4". Therefore, it will NOT work on an LQ4 block. Just use the 6.0 GM MLS gasket or alternatively, the '99 graphite 6.0 gasket if you need a thinner gasket. I have sucessfully used the 6.0 gasket on blocks that have been bored .030" over. The easy answer is as long as a gasket meets 3 basic requirments, it will work for a given application. First and foremost, the gasket bore diameter must be larger than both the bore AND chamber. Second, the sealing surface must completely surround all coolant passages. Third, the thickness must allow for adequate piston to head clearance. As far as the Darton MID/Cometic gasket vs the LS7 GM MLS gasket, you will have to compare the coolant passage sealing surfaces to see if it is adequate. The Darton MID gasket has signifigantly different embossing to deal with the unique coolant passage configuration of the Darton MID system. I'm not saying the LS7 gasket won't work, I am just saying you had better check... Also, I have successfully re-used the Cometic gaskets after coating them with Copper High-tack.
Thanks,
Shane
The stock LS1 5.7/5.3HO GM MLS Gasket has a bore diameter of less than 4", I didn't make an exact measurment, I just know it was at least .030" less than 4". Therefore, it will NOT work on an LQ4 block. Just use the 6.0 GM MLS gasket or alternatively, the '99 graphite 6.0 gasket if you need a thinner gasket. I have sucessfully used the 6.0 gasket on blocks that have been bored .030" over. The easy answer is as long as a gasket meets 3 basic requirments, it will work for a given application. First and foremost, the gasket bore diameter must be larger than both the bore AND chamber. Second, the sealing surface must completely surround all coolant passages. Third, the thickness must allow for adequate piston to head clearance. As far as the Darton MID/Cometic gasket vs the LS7 GM MLS gasket, you will have to compare the coolant passage sealing surfaces to see if it is adequate. The Darton MID gasket has signifigantly different embossing to deal with the unique coolant passage configuration of the Darton MID system. I'm not saying the LS7 gasket won't work, I am just saying you had better check... Also, I have successfully re-used the Cometic gaskets after coating them with Copper High-tack.
Thanks,
Shane
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Just an addition to this discussion. The LS7 gasket is made specifically for the LS7 block. The water passages on top of the cylinder are shaped just a little different. The LS1 style gasket may work on an LS7 block, but those water passages are just a liitle obstructed. When i was building my 427 someone sent me a set of cometic LS1 style 4.160" gaskets for my LS7 block, and LS1 style heads. I called Cometic twice about this and they told me both times not to use those gaskets on my LS7 block. They told me I needed LS7 gaskets. I could not get the Cometic LS7 gaskets, so I bought the GM gaskets. Worked perfect for me. Close as I can tell, they are .060" installed thickness.
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