Anyone have direct experience with LS9 vs LQ4 head gaskets, coopering?
Setup is 370ci, PT7875, LS6 cam, stock 317s, E85, 20psi, ARP hardware, etc... somewhere around 1000 crank hp.
I'm assuming my back pressure is decently high due to the small turbine and my ci and power level.
My main question here is are the LS9 gaskets going to help me any over the LQ4 gaskets that I've been running, or should I look into another solution all together? I've gotten a quote for camaroandreas's coopering setup, and it is sort of pricey but I'm willing to do it if it's the next best option short of buying beefier heads.
So, does anyone have LQ4 vs LS9 gasket experience? Or comments on the coopering setup? I'm all ears.
Thanks,
Adam
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I assume you're using ARP studs ? Torqued to ?
Perhaps a better stud ?
Or if pushed, maybe go to 1/2" studs.
But using normal ARP studs with basic 5 layer LS2 gaskets on mine Ive never had any issues. Torqued to 75lbft I think I did last time.
It's also very easy to keep an eye on things by monitoring pressure in the cooling system. This will tell you almost immediately how the gaskets/setup are performing.
I assume you're using ARP studs ? Torqued to ?
Perhaps a better stud ?
Or if pushed, maybe go to 1/2" studs.
But using normal ARP studs with basic 5 layer LS2 gaskets on mine Ive never had any issues. Torqued to 75lbft I think I did last time.
It's also very easy to keep an eye on things by monitoring pressure in the cooling system. This will tell you almost immediately how the gaskets/setup are performing.
I'm running the 3 layer gaskets. I'm going to try the LS9s and see how it goes. I think they are a 5 or 7 layer right?
Good idea to keep tabs on the coolant system pressure. I think I will look into that. Very easy way to keep and eye on it.
Thanks for the replies everyone!
Some do go to 80lbft, but I didnt bother. Although my 75lb was re-torquing after a few hours. ie loosen each one in turn 180deg then retorque one at a time
This often does see another 30-45deg of rotation.
Ive only ever used the 3 and 5 layer GM gaskets. Only downside against the LS9, is they'll be a lot larger than your bore size.
My method: Clean surfaces until your rags don't come off with any stains using lacquer thinner. De-burr any raised edges, Torque them dry and only use ARP Ultra Torque lubricant when torquing them. It's the only product that will provide you with a reasonable guarantee you'll hit your yield on the first torque attempt.
Some 3-layer gaskets (LS7) cover steam holes and will enhance the problem. Have you ever checked the alignment of those holes??
Here's a quote with pics from the original post that first turned me on to this issue.
LS7 gasket on 02 LQ9 block....




Old 6.0L gasket fits much nicer....


LS7 gasket, note the black area on the bottom where it was pushing water,

The new gaskets will be here tomorrow, and I will compare the LS9 gaskets.




I'm sure my cylinder pressure is up there. For the price of the LS9s, I'll give them a shot. Anyone coating their gaskets on install?



