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Discussion Starter #1
Built an LQ9 based 408 this February with single 88mm S500 in my F-Body. Ran pretty aggressive timing with car while still hot air using C16, assume that's where the head gaskets started failing. Since, intercooled now and has gone 8.70 @ 162. Though that was just last week, felt car had been dropping off and has been pushing coolant for a while now. I was using ARP studs in my PRC heads torqued to 85lbs with moly lube and cometic gaskets. Just tore down and found 5 of 8 leaking! I see many variations of sealing - what would work for street use too? Copper ring in block with MLS gasket? Or steel ring with Graphite gasket? Ring and receiver groove?

I am running 20lbs - looking to go to 24-25 range.
 

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Discussion Starter #3
If you are going to run an O-ring, SS O ring in block receiver groove in the head with a copper head gasket.
What about coolant leaks I keep hearing of with copper? I do street drive car, so would rather not. My Machinist and Felpro both say use MLS with SS ring. I was thinking of copper ring with MLS or prefer LS9 with copper or ss ring if able.

Or is the feeling that with 1/2 studs I will have all the clamping I need? I do not want to limit to 25 lbs - Though I do not plan to go higher.. Who knows.

Thank you for reply.
 

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The factory LS9 gasket should run [email protected] if your car/truck is under 4000lbs with two good surfaces and good fasteners. If you are having trouble now sealing it better will just move the breakage elsewhere, probably bent rods. Cool your intake charge and run the timing down around 14 degrees with traditional heads. That should run your goals while controlling water as well as the factory cars.

Kurt
 

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Discussion Starter #5
The factory LS9 gasket should run [email protected] if your car/truck is under 4000lbs with two good surfaces and good fasteners. If you are having trouble now sealing it better will just move the breakage elsewhere, probably bent rods. Cool your intake charge and run the timing down around 14 degrees with traditional heads. That should run your goals while controlling water as well as the factory cars.

Kurt
Thanks Kurt, those were not my goals - That is where I was when I tore car down.. I plan to go much faster - need to work on chassis efficiency of course.

Thanks for help.

Not sure where I am going to go - Copper with rings is nice for piece of mind.. ls9 gaskets with 1/2 studs seems much easier. Block is at machine shop now - I better decide soon.
 

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I have copper gaskets and oring block with the receiver in the head on an lq9 408 street car and have no problems with it leaking, hadn't put any boost to it yet though. I've always heard if the machine shop does it correctly then it shouldn't leak.
 

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i know its a different engine. but I just went through this my self. between this site and my machine shop. I went with a SS o-ring and a receiver groove in the head gonna use a Copper HG.
 

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Discussion Starter #11
i know its a different engine. but I just went through this my self. between this site and my machine shop. I went with a SS o-ring and a receiver groove in the head gonna use a Copper HG.
Thank you.. That's what I'm doing.. seems like the right thing to do while apart.. Seems LS9 will do trick, but what will copper hurt? Might as well get all the sealing I need now while apart.
 

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Can anyone actually shed some light on the whys of a copper gasket?

What makes the copper seal combustion better than a multi-layer steel?
 
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