head torque w/ cometic hg
#1
head torque w/ cometic hg
Have heard when using a cometic head gasket you should over torque to prevent leakage. I'm using stock head bolts. Only running 10 psi out of a t28 Garrett. Putting car back together and want some opinions. Just want my daily driver running not worried about after market head bolts or anything like that building a snub noes for 30 psi and ill do that one up right. I just need to get to work and need to know what people think about torque specs. Thanks
#13
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Original arp spec was 49. We use 65, which is what the instructions I got with my first set said. Current spec is 80, and apparently that will crack it. Arp doesn't seem to care about fixing their instructions.
I don't know or care about factory specs.
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I'm bored so here is a bunch of fastener information from a way too in depth gasket presentation I attended at IMIS:
-Clean the black oxide coating off of the threads on the ARPs if you want a consistent torque value. Muriatic acid will take it off quickly. The coating increases friction and will result in less clamp load with the same torque wrench value.
-Check the threads using a thread gauge. A dinged thread will increase torque reading.
-Don't use ARP moly lube. They came out with a new "super lube" or something that is better. ARP moly lube results in inconsistent readings with re-torques.
-A "cold retorque" can be performed and will result in more even clamp load. To perform a cold retorque you torque the gasket up as normal and then back 1 fastener at a time off and retorque (in the normal pattern).
/answers to questions no one asked
-Clean the black oxide coating off of the threads on the ARPs if you want a consistent torque value. Muriatic acid will take it off quickly. The coating increases friction and will result in less clamp load with the same torque wrench value.
-Check the threads using a thread gauge. A dinged thread will increase torque reading.
-Don't use ARP moly lube. They came out with a new "super lube" or something that is better. ARP moly lube results in inconsistent readings with re-torques.
-A "cold retorque" can be performed and will result in more even clamp load. To perform a cold retorque you torque the gasket up as normal and then back 1 fastener at a time off and retorque (in the normal pattern).
/answers to questions no one asked
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