copper head gasket
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yeah they do list some flatness tolerances ill just bring em to my job and mill em flat seems like they dont want to comment on it but i heard you were supposed to use some copper metal spray and coat both sides but who knows maybe ill try them again
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328 Posts
yeah trying to get s straight answer from sas if im supposed to use a sealent or just throw it on and crank it down. general consensus is use the spray but its a built motor shooting between 500 -550 hp so thats where the question is to use or not to use sealent.
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13,149 Posts
I know absolutely nothing, but I'd probably try with sealant... hose the whole thing down, including the fire rings. I think this setup (aluminum head on iron block with copper in the middle) is gonna be leaky, so lacking any actual guidance I'd do everything I could to reduce those chances. (Not talking out of my ***... ran a copper gasket on a c900...)
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13,149 Posts
TBH I think the stock head gasket. At some point the stock bolts give up and you need to use studs, but I'm not sure where that crossover point is. In my head I remember JZW or Nick having an opinion on that, and I'm sure it's in the 500+hp range.
This is 100% my ignorance, but in today's terms I don't know what copper gaskets actually solve. In the old days of simple gaskets and less advanced clamping there was definitely potential value from copper, but modern MLS gaskets with the right hardware can withstand a LOT of pressure. On my XR4Ti I use a Cometic MLS gasket and ARP studs - it's been handling 25psi for 15 years. In the GM world, I see people making close to 1000 boosted hp on stock LS-whatever gaskets. A friend has a 600hp Ecoboost Mustang on a (revised) factory gasket... It's at least 25psi and it could be 35psi. MLS gaskets are quite good.
My suspicion (I don't know) is that on a Saab the big issue is clamping. The stock bolts aren't super strong, and they're TTY, so it's probably possible to generate enough cylinder pressure to loosen the bolts and that will blow out the gasket quickfast. If you have adequate clamping, I think that gasket is going to take a lot of pressure. The problem of course on a mixed-material motor (iron block, alloy head) is that you have different expansion rates... the MLS gasket and TTY bolt configuration is designed explicitly to handle that. When you change over to studs, you will lose that elasticity that keeps everything together. That may end up with secondary issues, which is probably why Nick doesn't recommend studs until you absolutely need them. On my XR, the head and block are both iron (yay?) so that's not a concern for me.
But studs on a mixed motor will probably result in a relatively short lifespan for the gasket and/or ongoing need for retorques. Of course, ARP's metallurgy is quite good, so who the **** can predict what actually happens? Maybe that's a reason to use copper? The gasket probably won't blow out if you lose clamping? IDK.
This is 100% my ignorance, but in today's terms I don't know what copper gaskets actually solve. In the old days of simple gaskets and less advanced clamping there was definitely potential value from copper, but modern MLS gaskets with the right hardware can withstand a LOT of pressure. On my XR4Ti I use a Cometic MLS gasket and ARP studs - it's been handling 25psi for 15 years. In the GM world, I see people making close to 1000 boosted hp on stock LS-whatever gaskets. A friend has a 600hp Ecoboost Mustang on a (revised) factory gasket... It's at least 25psi and it could be 35psi. MLS gaskets are quite good.
My suspicion (I don't know) is that on a Saab the big issue is clamping. The stock bolts aren't super strong, and they're TTY, so it's probably possible to generate enough cylinder pressure to loosen the bolts and that will blow out the gasket quickfast. If you have adequate clamping, I think that gasket is going to take a lot of pressure. The problem of course on a mixed-material motor (iron block, alloy head) is that you have different expansion rates... the MLS gasket and TTY bolt configuration is designed explicitly to handle that. When you change over to studs, you will lose that elasticity that keeps everything together. That may end up with secondary issues, which is probably why Nick doesn't recommend studs until you absolutely need them. On my XR, the head and block are both iron (yay?) so that's not a concern for me.
But studs on a mixed motor will probably result in a relatively short lifespan for the gasket and/or ongoing need for retorques. Of course, ARP's metallurgy is quite good, so who the **** can predict what actually happens? Maybe that's a reason to use copper? The gasket probably won't blow out if you lose clamping? IDK.
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2,599 Posts
Good call on ARP studs. Only way to fly.
In regards to head gaskets, I’m at 1130 horsepower in my 2017 Camaro SS using Cometic MLS head gaskets. No drama.
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