qsgto
New Member
Posts: 2 
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Post by qsgto on Apr 13, 2015 17:37:54 GMT -5
I built a forged LS2 for my 2005 GTO with 9.7:1 CR running E85, 20 PSI boost and a 200 shot of NOS that dynoed 987RWHP and 1045RWTQ. The Cometic head gasket blew out on the top side and acted like a torch melting away aluminum from head where it blew out, melted the electrode off and cracked the ceramic insulator on the tip of the spark plug. I have ARP studs too. Only 300 miles on motor. 4th time on spray. I'm not sure what caused it. Was the compression ratio too high, cylinder pressures too high from NOS and extra fuel or PRC 237 heads not have a thick enough deck to handle the pressure? Any thoughts here? What is the highest CR I should have with this setup? Thanks for your input.
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Post by butterbean on Apr 14, 2015 12:04:44 GMT -5
when you have that much cyl pressure you have to O-ring the block and use copper head gaskets, cometics are for high compression engines and engines with spray, they are only so good
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qsgto
New Member
Posts: 2
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Post by qsgto on Apr 15, 2015 0:35:01 GMT -5
I considered o ringing the block but I was told they almost always have coolant leaks. Cometic came out with a new gasket a couple months ago called MLX.It has a thicker fire ring and it is rolled to help it seal better. I was thinking about getting larger chamber heads to lower compression ratio and use these gaskets.
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Post by bigydaddy on Apr 15, 2015 16:48:13 GMT -5
check Steve Morris Racing Engines website. He doesn't like mls gaskets above 1000 hp(motor not rear wheel) due to them failing above that power level.
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